Home | Search Serendip
Serendip
From Serendip

An ongoing conversation on brain and behavior, associated with Biology 202, spring, 1998, at Bryn Mawr College. Student responses to weekly lecture/discussions and topics.


TOPIC 3:

If brain=behavior, then things learned about nervous system structure and function might be expected to change how one thinks about behavior. In this respect, how significant is or is not a better understanding of such cell level processes as action potentials and membrane potentials in general? If such understandings have changed the way you think about behavior, explain how and why. If not, discuss why you think they might or might not in principle do so.

(As in weeks past (and future), students were free instead to write instead on any other subject that struck them as particularly interesting during the week).


Name: Julia J
Username: jfjohnso
Subject: take it or leave it
Date: Fri Feb 6 15:46:23 EST 1998
Comments:
I certainly do not mean any offense here, but this week's topic didn't really get me riled up. Not that one needs to be fired up to have an opinion on something, but I feel that the structure of the "insides" of the nervous system make sense. It is a lil' nutty to think of the optic nerve and auditory nerves doing a switcheroo and the implications there, but all in all, I don't take issue with the whole setup. In fact, I was rather pleased to see how the potentials can arise, seemingly from nowhere. It had a somewhat calming and soothing effect on me to have that physical connection to store next to my visual images of the in/outboxes. Remember how I said that I was not riled up?

Perhaps what struck me most here was in looking at the larger picture. I am a firm believer in the larger picture. I like the idea that behavior is not caused but allowed to happen. I immediately thought of such things as panic attacks and disorders, general anxiety, depression, and maybe even compulsions. Do people just have an inhibitor in their nervous systems that, if turned off by a chemical imbalance or environmental trigger, will become activated, causing panic, depression, etc.? Obviously, it is more complex than that but it is a new way of seeing illness. If this was a widespread interpretation of the nervous system, I can see it having a huge impact on the stigma attached to certain illnesses, particularly mental illnesees.

So, there you have it. Now, if we could just find out what this inhibitor that affects paraplegics that can't be discussed in mixed company is....

Not bad for not being riled up. At least two ideas that one might productively spend a life time doing some looking into. And interesting how that comes from going back and forth between details and "larger picture", no? PG


Name: Julia J.
Username:
Subject: ooops
Date: Fri Feb 6 15:52:02 EST 1998
Comments:
I wrote above that a chemical imbalance or environmental trigger might turn off an inhibitor to the nervous system, thereby activating it. I shouldn't have used the word "activate."What I meant to say was that, if an inhibitor is turned off, the system is allowed to behave as it "wants." See what I am saying in terms of certain diseases?

Yep. PG


Name: Christy Taylor
Username: ctaylor@brynmawr.edu
Subject: Synaptic Transmission
Date: Fri Feb 6 16:56:55 EST 1998
Comments:
In response to this week of class discussions, the intricate connections between the nervous system and behavior are becoming increasingly relevant. It is essential to understand cell level processes - such as action potentials and membrane potentials because they have such a direct effect on behavior.

One of the most interesting topics is that there are neurons that constantly have a high concentration of sodium and therefore are constant generators of action potentials. We can relate this to the brain=behavior discussion because this insight helps to explain why humans can have behavior (output) with no apparant input.

A particularly relevant example of this is the pacemaker cells in heart. Just think if we had to consciously "think" about making our heart beat all day, every day as long as we lived? As absent minded as I am at times, I certainly do not think I would survive very long!!!

Furthermore, another topic that sparked my interest was the fact that since synaptic transmission is the way that one signal is passed from one neuron to a target, neurons are intimately connected and can have great influence on one another. Signals can be stopped in their tracks, slowed down, or even stopped simply by the influence of another neuron. It makes me wonder if signals can actually be "changed" by other neurons through synaptic transmission? It also brings to mind that some behaviors may not be caused by anything, but may simply be allowed to happen!

An interesting area to explore would be to study what suddenly is allowed to happen by the nervous system when a person's spinal cord is damaged or severed.

Lastly, I have been struck this week by the enormous complexity of the human body! It is no wonder that when a seemingly minor health problem may arise, that because of the body's interconnectedness, it can rapidly become something major or even life-threatening. As a future physician, it helps me to think about treating the person as a whole system, and not simply to look at the specific problem by itself.

Several interesting points, including the generalities that parts can work by themselves and wholes are lots of parts which, for some purposes, need to be thought about as wholes. Remember its not the sodium "concentration" but the sodium "permeability" that can lead to spontaneous generation of action potentials. PG


Name: jeremy hirst
Username: jhirst@brynmawr.edu
Subject: determined or predetermined
Date: Sun Feb 8 16:33:50 EST 1998
Comments:
this week I would like to discuss the nature/nurture debate in relation to the brain and behavior. how much of our behavior is determined by our genetic makeup and how much is determined by the environment we are exposed to and raised in? Are such behaviors as positive performance on IQ tests, outstanding omelet cooking, and excellent elephant training predetermined by the genes which coded for the specific makeup of our brains? or are they determined by something else, something more variable and controllable?

if brain=behavior then whatever makes our brains makes our behavior. I believe that the DNA sequence which was uniquely pieced together from our parental gametes is directly responsible for the such characteristics as hair color, size, predisposition to acquire certain diseases, and many other physical characteristics of our lives. It seems I can not escape the logical extension of these traits to include the actual "wiring" together of our neurons. is it the basic connections of our nerve cells which determine our behavior?

I hope not. I know twin studies are often referenced when discussing issues such as these, and that they are often full of frustrating confounding variables, but I would like to relate a short story of some twins I know. Two of my cousins are "identical" twins, one was born, however, with a misguided esophagus such that he could not eat. as a result he underwent many operations over the first nine months of his life. this extra stress and attention seems to have had a long lasting effect. he is now smaller and more reserved than his gregarious brother. Throughout the twelve years of their lives the smaller one has been give more babying, more reassurance and protection by their parents and everyone they come in contact with.

thus, they have experienced significantly different environments growing up, even though they have been raised together. I'm not sure where to go with the argument now, but it sure seems like a good one for environmental effects on behavior.

long term environmental stimuli which tend to elicit one type of behavior seem to override whatever genetic influence there may be on ones behavior.

how, then do I explain the amazing examples of slaves, prisoners, and the like which have survived horrendous conditions seemingly coming out stronger? I don't know....

I am hoping to come to the conclusion through this course that our behaviors are indeed determined in the present tense, rather then predetermined through means none of us have control over.

That would indeed be a satisfying place to get to, and I think we will. Not only because its satisfying but also because its the "best summary of observations" or "trend of the evidence". Yes, of course, genes INFLUENCE neuronal connection patterns (among other things, which also include permeabilities). No, they don't DETERMINE them (as is evident from a variety of things in "identical" twins, who do have the same genome but differ in general in a variety of ways, including, for example, finger prints). The question is, of course, what are the OTHER influences, how may are there, and how do they operate? We'll talk a lot about this as we go. For some foreshadowing, you might take a look at Serendip's section on Genes and Behavior. There's also a new book on twins, reviewed in the NY Times Book Review last Sunday,which I haven't read but looked interesting (Twins and What They Tell Us About Who We Are, by Lawrence Wright, John Wiley and Sons, 1998). Its on a list of books about twins maintained by Twinspace, "the website about twins", which might be an interesting window to further exploring that particular phenomenon. PG


Name: Meera Sangaramoothy
Username: msangara@brynmawr.edu
Subject: cellular activities
Date: Sun Feb 8 16:48:27 EST 1998
Comments:
I do not think that the details of cellular processes within the nervous system discredits the notion that BRAIN = BEHAVIOR. Instead, I think that the existence and techniques of action potentials and membrane permeability accentuate the intricacies of behavior. The cellular activities of neurons only let us better explain how the brain makes its connections between certain inputs and outputs and, thus, why particular outputs (behaviors) are carried out and favored over other means of outputs. A block in potential flow, a change in ion concentration, a drop or increase in polarity: all these things help the brain make those sharp turns on the road of nerve pathways. For example, if I feel an itch on my back, I have a natural inclination to scratch it with my hand. But if I choose, I can just ignore the discomfort and remain still until it went away. But if the itch was extreme, then I would have almost no choice but to relieve it with a scratch. Thus, the cellular activities in and around neurons change and their alterations and actions influence other cellular processes and potentials causing an overall variety of outputs which may change with the severity of an input (like the itch) or with the changes in inputs. Thus, the study of cellular potentials and the scrutiny of the nervous system on a microscopic level only enhances our understanding that indeed, brain still equals behavior.

Or at least gives us some underlying mechanics to increase our "faith" that this is so? You're right, though, that the "mechanics" make it a bit easier to understand (accept?) why things feel different and different times and why we act/react differently to different things. Do the mechanics help in other ways? PG


Name: Libby O'Hare
Username: eohare@brynmawr.edu
Subject: back to the basics
Date: Sun Feb 8 17:01:09 EST 1998
Comments:
Understanding the cellular processes of the nervous system is invaluable to thinking about behavior. The first time I learned about action potentials, membrane potentials, and synaptic transmission the way I thought about behavior changed drastically. It is daunting to think that everything we do can be accounted for by the propagation of an action potential down an axon, and the termination of that action potential at a muscle (or muscles). Look around you. Notice all the behaviors you are seeing. Physical manifestions of chemical and cellular properties--that's it. Or is it?

It's hard not to get caught up in the complexity of behavior. Think about taking a drink from a glass. This is a pretty simple behavior, and it is easy to understand how the cellular level processes of action potentials function to produce a physical manifestion of themselves in the lifting of the glass and the swallowing of the water. But now, think about the behavior of falling in love. There just has to be something else there besides concentration differences and sodium and potassium gates. People have been trying to understand and explain the experience of falling in love throughout all human history. This behavior just cannot be explained away like taking a drink can be explained.

So, where does this leave us? I don't think that explaining behavior in terms of cellular processes makes us inhuman, unfeeling machines. Rather, I think that this understanding adds more complexity to the human experience. It also gives us a solid basis for explaining simple, routine behaviors. But I'm still waiting (like a lot of others) for that "something more" that makes us who we are.

Fair enough. But ... does thinking of drinking a glass of water in terms of concentration differences and gates really "explain it away"? One is still drinking the water, and what is involved is, as you say, a dauntingly complex and orderly set of ion movements. Maybe "falling in love" is the same thing but even more complex? It doesn't get "explained away" either, just recognized as a set of ... ion movements, which is so complex as to achieve all of the extraordinariness of falling in love?

By the by, its February 14. Happy Valentine's Day everyone. PG


Name: Elaine de Castro
Username: edecastr@brynmawr.edu
Subject: Significance
Date: Sun Feb 8 17:15:32 EST 1998
Comments:
The understanding of cellular processes is very significant to our understanding of all behavior. Not only do these processes help to explain our everyday behaviors, voluntary and involuntary, but they can help diagnose disorders of the body.

Taking the nervous system into account means being able to give it some of the blame! In some cases of the disorder amblyopia, displaying a severe loss of vision, untraceable to disease or deformity in the eye itself, a malfunction in the nervous system is to blame. The cellular processes leading to this dysfunction are still being researched.

These cellular processes also account for conditions such as addiction. That the neurons in the brain can become tolerant of certain substances and can adapt to the drugged condition is surely something significant as a reason to understand the cell level processes. Receptors on certain (LC) neurons respond to opiates, inhibiting the neurons' firing, and eventually becoming tolerant. Understanding how this is possible can help in finding a way to rehabilitate opiate addicts.

In such ways, the comprehension (to the smallest detail) of the properly functioning nervous system can do a world of wonder in diagnosing and treating an organisms' disorders.j

Is good point, similar to the thinking about epilepsy with which we started the course. Studying the properties of neurons does, in a wide array of cases, turn out to yield insights which CAN be used to influence behavior (for good and, perhaps, for less good, depending?). And that, of course, is both an argument for the importance of cellular level processes and for the more general brain=behavior proposition. On the other hand, it also generally turns out that behavioral phenomena can be influenced but not fully controlled by cellular level manipulations (anti-depressant drugs, for example, work for some people, sometimes, but not all people all the time). Any idea why that is so? And what it implies about both the relation between cellular level phenomena and behavior and the more general brain=behavior proposition? PG


Name: Anneliese
Username: abutler@brynmawr.edu
Subject: response to jeremy/own speculations on this week's topic
Date: Sun Feb 8 17:46:22 EST 1998
Comments:
Before I talk about some of the thoughts I had in response to this week's lectures, I wanted to post my reactions to the essay you read just before this one. If there's any trend I seem to be noticing, in terms of causal explanations of various phenomena in biology, it's that there aren't very many "either/or", "black or white", "all or none" cases. I suspect the same is true for determinants of behavior. One can't deny the deterministic qualities of DNA; it codes for the production of proteins, including those in the neuronal membrane. I can see the possibility of some individuals having more efficiently operating channel proteins, for example, perhaps allowing neuronal activity to work a bit faster than for others. Nonetheless, neurons can change, alter their individual properties, or be altered by external factors (though I'm not exactly sure yet how, I know they do--see book!). Thus, while I believe that there are certain limits to our capacity to control and shape our behavior, our fates are not sealed entirely by our genetic make-up, and there is a great deal more room for flexibility and growth.

I was reading the other entries, and my attention was caught again by the notion that much of our behavior is the result of things being "allowed to happen". It set me thinking along the following line: if abnormalities, malfunctions, etc., are the result of the failure of excitatory/inhibitory postsynaptic potentials to create the action potentials necessary to prevent such malfunctions, then not only might we have a clue as to the causes of some types of mental illnesses (as stated above), e.g. OCD, but also a potential explanation for the mental deterioration that seems to accompany aging.

Seeing my grandmother getting old and losing more and more of her memory, becoming increasingly delusional, I've wondered, as I'm sure many of you have, whether this is inevitable. Are her neurons undergoing a process of entropy, moving towards an ever increasingly disordered state? If so, then why is it that despite her inability to remember something I said just a few minutes before, she can recall with clarity and precision scenes and experiences from her childhood?

I remember reading in this wellness/nutrition healthletter that old people don't think any worse than their younger counterparts, just that it takes a bit longer; that if you give them time, they are quite as able as someone half their age. It also said that to counteract the effects that aging has on one's memory, one should keep one's brain active, do crosswords, et al. Does this mean that if we continue to stimulate our brains, send input to our neurons, that they keep working better? Does input to the brain become increasingly important as we grow old, or is it that it is just as important at any age and that it tends to decrease due to our decreased activity?

Funny how thoughts tend to come together...going back to Jeremy's essay, in light of what I've just written, it seems that our behavior (->activity) does have a rather important role in determining our lives. Neurons create certain involuntary behavior and allow for other potential behaviors; whether or not/how we make use of or choose among the opportunities presented to us by our biological make-up in turn impacts on the functional elements, and so on, and so on...I think we need to stop thinking in hierarchies and straight lines and take the circular route. Or maybe spirals...Hope this makes sense to whoever takes the time to read it--I have a tend to think as i write (but let's leave that for another time).

Wonderful links to your own experiences, others thoughts, all in and around the course material. Very gratifying, just what the forum is supposed to make possible. Many thanks. There's a lot of interest/action these days on the aging phenomenon, which is still pretty poorly understood. See this Sunday's New York Times magazine for an interesting and provocative article on the ongoing development of "memory enhancing" drugs.

Along more conceptual lines, you're right of course that there is an increasing understanding that things in biology (including the brain) have in general multiple rather than single causes (I remember when this thought first hit me, in the context of some research I was doing more than fifteen years ago, and actually cowrote a paper on the subject, which isn't on Serendip but perhaps ought to be). And that there is a general "loopiness" in causation, so that things which affect other things are in turn affected by them. With the bottom line indeed being to suggest there is plenty of "room for flexibility and growth". We'll try and make all that more concrete for brain and behavior as we go on. PG


Name: Anneliese
Username: abutler@brynmawr.edu
Subject: correction
Date: Sun Feb 8 17:49:52 EST 1998
Comments:
Sorry, it seems that some folks posted before I got a chance to, which calls for a minor addendum: the "last essay you read", with respect to mine, is Jeremy's.
Name: Dena Bodian
Username: dbodian@brynmawr.edu
Subject: Falling in Love: The Neurobiological Explanations
Date: Sun Feb 8 20:29:31 EST 1998
Comments:
I'd like to attempt to respond to the statement that behaviors associates with being in love couldn't be explained in terms of chemical reactions. As cold-hearted and analytical as it sounds, I beg to differ. In humans (as in all mammals) sexual attraction derives from positive reactions to various stimuli (the person with whom one is enamored). It has been proven that certain faces are aesthetically pleasing simply because of the way they are processed by the optic nerve and the brain. Studies have also found that particular characteristics which suggest the ability to be good breeders (such as larger breasts) are deemed attractive on a most sub-conscious level. (This also explains why adolescent boys act like animals.) Voices which we deem pleasant are merely vibrations that resonate well in our ears. Pheromones are another means of attraction: supposedly, couples who enjoy each others' scents are much more likely to remain together. Could this be the reason why so many people are attracted to greasy, sweaty men who may have few practical attributes?

It is no wonder that with all of this input, our senses often feel bombarded when we encounter another person to whom we are attracted ó if only for biochemical reasons. This onslaught of the senses is universally identified by medical symptoms: sweaty palms, racing pulse, a "sick" feeling in the stomach ó all possible chemical reactions, caused when one comes in close contact to the beloved. There is no cure for the common crush. However, it is possible to identify and explain its symptoms in an attempt to do what humans have been attempting to do for many millennia: define the incredible emotion we call love.

Nice addition to the set of thoughts on this subject (will decline to feel incorporated into class of ... having "few practical attributes"). To which we might also add some of the above conversation: behavior has an enormous number of influences, few "determinants" and some earlier conversation: every brain is different. So "has been proven" is a little strong and a little sweeping. On the other hand, both odor and symmetry are unquestionably factors of significance in a significant number of people. I'm not sure I'd want to deprive people of the experience of "the common crush", but maybe knowing more about some of the factors involved would help people avoid some of its sometimes less satisfying consequences? PG


Name: Rachel Kaplan
Username: rkaplan@haverford.edu
Subject: the love equation?
Date: Sun Feb 8 20:30:47 EST 1998
Comments:
In Libby O'Hare's essay, in reference to falling in love, she mentions that "there just has to be something else there besides concentration differences and sodium and potassium gates." I agree wholeheartedly; though, I do believe that much of this wonderful & mysterious phenomenon can be explained by examining processes in the brain.

In Love: is it really all in your head, brain scientist Karl Pribram talks about the fact that "apart from individual psychological influences, there are a myriad of overlapping brain signals and processes that are involved in love and sexual attraction." His theory involves 3 specific regions of the brain in addition to pheremones: a steroid regulating hypothalamic portion which is located in between food and temperature regulatory centers, the amygdala which is involved in producing the symptoms of someone "in love" such as distraction, heightened physical sensitivity, and apathy towards things such as eating and drinking (Pribram), and the frontal lobe which is associated with "motivation and commitment" (Pribram). The pheremones are said to "stimulat[e] arousal centers in the brain" (Pribram).

Pribram is quick to make the distinction between being "in love" and being "loving." Being "in love," he says, involves being passionate and this "in love" state is associated with a unique brain chemistry.

What this scientist has to say makes a lot of sense to me. Especially because his ideas do not exclude other factors involved in "falling" or "being in love" such as "availability, feasibility, mutuality, compatibility and commitment" (Pribram).

Despite the involvement of other factors, the views outlined still strike me as too reductionist. I feel uneasy about the idea that love can be explained away; although, I do not reject the possibility. It just seems that if the above is true than it may be possible one day to plug yourself into an equation on a computer (i.e. 2 * constant + you = your love), push a button, and voila...out comes a description of your ideal mate. I think a lot of the fun is in exploring and through that learning what works for you and what doesn't.

The link is actually to an article quoting Pribram, but neither less nice nor less relevant for that. Pribram though may be thought of as in the "fewer practical attributes" class (see above). Helen Fisher, mentioned in a recent Inquirer article, is an anthropologist who actually more directly involved than Pribram, in thinking about love in relation to the brain. Regardless of where it comes from, the story indeed seems to be that (as above) there are lots of factors in "love", not just one. The question is, as you say, given THAT, is there STILL something too "reductionistic" about the whole approach. Does it "explain away" love, and if not, why not? I like your way of looking at the problem: could one measure everything and come up with "ideal mate"? Probably not, since the "exploring" and learning probably changes the definition itself. So we're back to process (see above and last week) and, perhaps, to the brain? PG


Name: Eric Odessey
Username: eodessey@haverford.edu
Subject: In awe of the brain
Date: Sun Feb 8 21:11:09 EST 1998
Comments:
The details behind the concepts of neurotransmission are generally not new to me. The more I learn about the biochemistry of the nervous system, however, the more awe-inspired I become at the brilliant evolutionary process. The fact that all thought and behavior results simply from a potential difference across neural membranes is a difficult concept to grasp. All parts of human behavior must be so precisely coordinated for nearly any activity to be successful. Take, for example, catching a ball. Your eyes constantly receive input and transfer the information on the ball's angle and velocity to your brain. Your brain instantly processes the information, then tells your arm to raise and your hand to close at exactly the right instant. To do this, the brain must even factor in the lag time for the motor signal to get to your hand. The brain performs all these decisions virtually instantaneously.

The ball-throwing example is one of the simpler actions. It is much more difficult to explain the process by which memories are stored or dreams are experienced. Evolution has dictated the development of a bafflingly intricate and complex system to form human behavior. We are left to ponder, open-jawed, the seemingly abstract, spontaneous creation of thoughts and actions formed merely by the flow of ions with a concentration gradient. Truly spectacular.

Spectacular indeed. Both as the outcome of a process (evolution) and as the process itself (the details of what is occuring at any given time). And, of course, as a process (what is occuring now) which is part and parcel of the larger process, hence presumably both reflecting it and altering it. From which several general issues emerge needing to be explored in the specifics. What achieves the "coordination"? What properties and interactions are needed to account for the outcome at any given time? Is now the end of the process or only the particular stage we happen to be in? What role do we play in what happens next? And what are the consequences of whatever role we play for that? Are the concepts of neurotransmission enough to approach such questions or is something more needed? PG


Name: Karen Taverna
Username: ktaverna@brynmawr.edu
Subject: nothing more than feelings
Date: Sun Feb 8 21:16:17 EST 1998
Comments:
All this talk about love...

Love is probably one of the most obsessed over "feelings" which is definitely not a bad thing. After skimming through the previous responses the "love" debate caught my attention and I began to thing about other emotions.

Why do people cry? Or how? And why all the other things that go along with it. Sometimes there will just be tears, other times loud sobbing, sometimes there is the chin quiver-etc. My actual question is why do tears go hand in hand with emotion--people cry when they are happy, sad, scared, mad, etc. and sometimes they don't. Going along with the equation that brain = behavior, any action is caused but neurons firing. So that is what causes tears. In that case the conclusion can be drawn that the "feelings" neurons are associated with the "tear" neurons- but why? Why do I feel like crying when I see a sad movie? Is it a necessary reaction? Certainly not necessary for survival- crying in the movie theater is not going to save my life or someone else's life - like the actor in the movie. In this case tears seem futile- all I get in the end is a pair of puffy eyes.

I understand the psychological benefits of crying and not "bottling up" those emotions but I can't help but wonder just why people cry. It would be fun to open up someone's skull and look into their brain. If people were cartoon characters, I would be able to follow the path of sparks to see exactly where "tears" originate.

Interesting image/thought. With modern imaging techniques its actually getting increasingly close to possible to see the "sparks" in real people even without opening up the skull. As a thought experiment: imagine that you CAN see the sparks of someone sitting in a movie theater starting to cry. Try and imagine all the possible ways it could look. Are there some of them which would allow you to say where tears originate? Any of them? PG


Name: Rani Shankar
Username: rshanka1
Subject:
Date: Sun Feb 8 23:13:30 EST 1998
Comments:
How has learning more about the cellular basis of neurobiology changed my notions of behavior? It hasn't necessarily changed any particular ideas or concepts with respect to the brain=behavior debate, but it does complicate the argument. Somehow, the more players, i.e., generator potentials, neurotransmitters, membrane permeability, and ion channels, etc., we introduce into the picture, the more we have to account for when trying to sort through a specific behavior. That's understandable. Knowledge of cellular processes such as membrane and action potentials sheds light on the mechanics of isolated nerve impulses, however, what we observe in ourselves, in each other, and in other life forms is much more complex and coordinated. How can we piece together individual strings of coordinated potentials? Better yet, how does the process of integration occur- how is it that neurons can make decisions on what behavior to exhibit ? Par exemple, the chicken with it's head cut off. How is it that the chicken has a shutting-off mechanism that normally inhibits the constant tendency to run around like crazy? This example points out that we can't always think about behavior linearly. Maybe, the purpose of integration is to process a bunch of impulses, sort through them, prevent some from being exhibited, and allow some behavior patterns to be presented. As we begin to boil down the mechanisms of neurobio into batteries, channels, and ions, it becomes easier, and at the same time harder, for me to conceptualize the inner workings of the nervous system.

Fair enough. And probably as it should be (or at least has to be). Yes, because there are all those things going on behavior is quite rich. At the same time, knowing there are all those things going on requires us to try and say how they happen to be there (at least a different phrasing, maybe more useful?, of the "why do we cry?" question), and how they are coordinated (maybe, actually, the same question? if the coordination is inherent in the things being there in the particular arrangement they are?). We'll see how we do with these questions as the course goes on. PG


Name: Rachel Mosher
Username: rmosher@haverford.edu
Subject: learn cell-level processes?
Date: Mon Feb 9 00:40:00 EST 1998
Comments:
The question posed, how important is it to know intricate cell level processes to the understanding of brain and behavior is a tough one. I have two conflicting responses. Initially I thought (as the cynical student that I am) we are often forced to learn and memorize minute details of different areas of study for tests and such. The hard work we spend learning these details is quickly erased soon after the test when we forget every bit of what we memorized. Often, the only residues of a class are general ideas which do not require the knowledge of any intricate processes. As a result, when posed with this question my first response was that it is not important to know cell-level processes to understand brain and behavior. It is just a ploy teachers use to make their students miserable. After thinking a bit more about the importance of knowing the cell level process, however, different ideas came into my mind. If we can understand exactly how the brain converts external and internal inputs and interprets them into behavior, we might be able to apply this knowledge to answer important questions raised. For example, we are able to answer why there are outputs without inputs. (As we discussed in claass) Another question we would be able to answer is why people in the same environment can have different behaviors? (Why would genes influence action potentials?) This information could also be applied to benefit people in the mental-health field; if someone is behaving in a way that is destructive to him/herself and those around him/her, is it possible to alter their system to change their behavior? Would altering the behavior have any negative side affects? I suppose these questions have already been considered and have resulted in drugs such as prozac. If we hadn't bother to learn about the cell-level processes, however, we wouldn't have been able to understand that certain behaviors are caused by specific unbalances in the system. Further research will most likely reveal more advances in helping people's behavior and mental state in general- this is important. The most important thing this knowledge would bring us, however, is a clear picture of exactly what is happening to us inside. This will take the magical aspect out of behavior and make it easier for us to understand and accept others' behavior. With those thoughts in mind, I think that it is indeed important to know the cell-level processes that occur in the brain and spinal chord.

Yeah, I too have the feeling that people sometimes learn things because they're told to and quickly forget them (and share your suspicion that there is some conspiracy to do this "to make students miserable"). Hence the question. And I like your answer. Yes, at least some behavior level questions get at least partial answers from looking at cells. Yes, it can help with mental health and other clinical issues. But, most importantly for me, it does seem to "make it easier for us to understand and accept others' behavior". And our own. Wonder why that is? In terms of neurons? PG


Name: Allison R.
Username: arosenbe
Subject: da nervous system
Date: Mon Feb 9 00:47:58 EST 1998
Comments:

I think it is very significant to understand the details of action potentials in the cell because in order to comprehend behavior as a whole, we first need to understand the parts that make it up. Cells and action potentials within the cells are the little parts that make up how we react to things and situations around us. Potentials are key to our behaviors.

My thoughts about behavior in general haven't changed much, but I feel I understand at least the beginnings on how behaviors are formed. I find it interesting to think of information flowing through our cells in waves of permeability. Since the signals are not electrical, it takes time for signals to travel through the body. This may even be an acceptable reason for why people trip over things or are unusually clumsy- it may just be because their nervous system had a considerably longer time delay than others in reacting to obstacles. Or perhaps, they could just be absentminded (of course I'm not talking about myself).

The thing that both interests and scares me is the fact that all the action potentials are the same throughout all neurons. The only difference lies in which neurons are carrying the signals and where they are being carried to. If by some freak chance there was an accident and someone's sensory connections were confused, the person would never be able to actually see with his eyes or hear with his ears again. They would forever "see" thunder and "hear" lightening. I think this is something to be concerned about, but I'm not even sure if this could actually happen though.

There are indeed known situations in which there are easily observable alterations in "wiring patterns" in the brain. Ocular albinism, a genetic condition, is one such case. If one accepts that every brain is different, one might also suspect that, to one or another extent, everyone's connection pattern is a little differenet and so everyone to some extent sees/hears things differently? We'll talk more about this, but it is indeed another place where knowing something about cell properties might help to better understand one's own behavior and that of others. PG


Name: Meredith Ralston
Username: mralston@brynmawr.edu
Subject: neurons, and the idea that college students might sleep
Date: Mon Feb 9 02:18:05 EST 1998
Comments:
It's absolutely astounding to go from considering one's thought processes to examining a single neuron firing. The fact that complex thoughts and actions are based essentially on whether or not an action potential (alright, lots of action potentials) occurs is slightly staggering. The seemingly "yes or no" nature of it is reminiscent of binary, which might be the reason why people continue to make the awkward comparison between the brain and the computer.

Considering brain function in light of cell level processes is definitely crucial. A simple proof is that as students we need to remember that the brains we rely on are made up of cells need nutrition and rest, and so we need to eat and sleep. The most obvious examples of the significance of understanding neurons involve brains which are different from the "norm." Attention Deficit Disorder, as controversial as it may be, should represent a step forward for medicine and psychology in the long run. By discovering the biochemical basis for childrens' uncontrollable or excitable actions, the way we view their behavior has been changed. We may hopefully now deal more sensitively and efficiently with this difference.

Yes, action potentials suggest a "binaryness" of brain function. But also, yes, thats probably misleading, given that the frequency of action potentials (a continuous rather than a binary variable) is certainly a relevant parameter, and that the membrane potential varies continuously as well (in fact, some neurons use that as their inputs and outputs, without ever converting to a binary form). And, even more yes, awareness of the cells and their properties is a good reminder to eat (among other things). As for ADD, I very much share your hope that it will be "a step forward for medicine and psychology in the long run", of exactly the sort you suggest. PG


Name: Anne Frederickson
Username: afrederi@haverford.edu
Subject: Action Potentials
Date: Mon Feb 9 14:51:31 EST 1998
Comments:
I really don't have any problem believing that all of our behavior, thoughts, emotions, etc. are controlled by action potentials or the lack there of. In fact, I find it incredibly intriguing. Overt behavior is not so amazing to think of in terms of biological processes. Emotions, however, are. I was especially intrigued by the person who brought up love. I will admit that it may seem inhuman to think of the feeling of falling in love as a difference in ion concentrations but it seems like a reasonable conclusion based on the studies that have been done into other emotions such as depression, anxiety, and extreme happiness. Thinking of emotions in terms of cesses poses another problem - how do we explain the differences in emotion that people who are in love report? Not everyone who is in love reports the same feelings. In fact this applies to any emotion that we may want to talk about. If we are going to assume that emotions stem from the same biological processes in everyone, then wouldn't we conclude that people should report the same sensations when they are experiencing the same emotion? (This is the point where I am continually amazed) The differences have to lie in how the individual neurons are connected. No where else in the body does the positioning of a single cell make so much of a difference. If the heart has a few hundred cells change location, not much happens (unless it is a cancerous tumor of course) but if the nervous system changes where a couple hundred cells synapse, it could mean a huge difference in how people experience emotion.

Nice point, well made. Indeed, the "same" thing may be quite different in different people, because of the extraordinary dependence of nervous system function on the details of its organization. So the "same biological process" may in fact be substantially different things when looked at at a sufficiently high level of detail. PG


Name: L. Pernar
Username: lpernar
Subject: Significance
Date: Mon Feb 9 15:34:33 EST 1998
Comments:
As stated in the first one of these comments, brain = behavior makes sense for me. Hence, the closer look at the functioning of single neurons frankly fills me with awe for the types of behaviors we are capable of performing. The homeostatic mechanisms leading up to establishing the membrane potential , the processes leading up to an action potential, and the steps in synaptic transmission (i.e. the synthesis of neurotranmitters, and the release mechanisms, as well as the breakdown systems) are in their own right so complex, that the "simple" movement of a limb immediatly seems like one of the most complicated tasks one could possibly embark on.

Essentially then, not what thoughts I entertained about behavior changed, but my appraisal of behavior did. Definetly, for a greater appreciation of behavior and in fact all functionings of the body, an understanding of neuronal workings is essential.

Yes, the details are themselves complicated, and that's impressive. Beyond that, is it a good thing or a bad? Useful or simply confusing, maybe even unnecessary? How does it depend on what one wants to do with it? PG


Name: Emily Varani
Username: evarani@brynmawr.edu
Subject: Potentials
Date: Mon Feb 9 16:02:28 EST 1998
Comments:
Is anyone else totally astounded by the idea that every aspect of behavior is dependent on potentials? I am awed by the theory that everything I do, or think, or feel is the product of concentration gradients and dynamic membrane permeabilities.

What an amazing structure this nervous system of mine is! At any moment, I am taking in, processing, and responding to a multitude of sensations; but, in fact, all that is really occuring is that my sensory neurons are allowing certain inputs to instigate a domino effect of potentials throughout by body and into my brain (which, in ignorance, I am considering my central processing unit).

However, I don't find the most amazing part of my nervous system to be its abilities--I am most impressed by its inabilities. It seems to me that this system is highly faulty. I can't help but think of all the events occuring around me that I am unaware of because they simply don't stimulate the proper neurons or enough neurons. Frankly, it's scary to realize that objects that I cannot see are passing before my eyes, materials that I cannot taste are in my mouth, and touches that I cannot feel are covering my skin. Let me now revise my exclaimation: What an imperfect (but amazing nonetheless) structure my nervous system is!

Nice thought, well worth keeping in mind in general and in connection with some of the discussion above (and earlier) about whether the products of evolution "make sense". Yes, both amazing AND imperfect. Overall, as well as, in different ways in each individual. Given which, how DO we do what we do? Discover things that we can't see/taste/touch? PG


Name: ingrid katz
Username: ikatz
Subject: the brain and language
Date: Mon Feb 9 16:03:48 EST 1998
Comments:
Recently an article in the Johns Hopkins newsletter caught my eye relating brain and behavior. The article, from the magazine's January, 1998 issue, highlighted research on babies and the brain, specifically focusing on the fact that the fundamentals of language may be developed earlier in childhood than was previously realized. If this is in fact so, it adds yet another complexity to the world of brain and behavior.

Language is THE essential component of expressing our beliefs, emotions, thoughts and dreams. It is, among other characteristics, what sets humans apart from other vertebrates - this abilty to express complex thoughts - this marvelous thing called language. Although there are permutations upon permutations of languages, dialects, slang, accents etc, the basic underlying tenet is that language is a visible and unique behavior that humans are capable of expressing. It is what sets us apart.

Thus, if one considers the biocehmical level of what is occuring in the brain - the synapses, the action potentials etc, one can gain further insight into behavior, specifically the behavior of language production and use. Without language, we would not be capable of producing such intricate thought processes in an organized manner. Let's consider the fact that I am dyslexic. What does this mean at the molecular level? Certainly, by considering what is occuring in simply writing this essay at the chemical level, one is perhaps better able to grasp the vast complexity of the brain and the ability it has to transfer such chemcial signals into the actions of our daily lives.

Certainly it is a bit disconcerting to fully embrace the brain = behavior in the most full notion, but it is essential to begin to at least consider the ramifications of such molecular intricacy translating to highly complex actions that only humans possess.

Interesting issue indeed: language and its development. The article you saw is actually available on the web: The Origins of Babble. Part of a general trend to recognize existence of abilities at earlier and earlier points in childhood. Is language really unique to humans is an interesting and still being debated issue, but certainly the extent of symbolization and creation of stable records of individual thought and experience is a distinguishing characteristic of humans. Is worth thinking about what THAT is in terms of neurons, and why we do so much of it. And yes, its worth thinking too about what dyslexia might (or might not) be in terms of neurons. My own guess is that it is more likely to have an explanation at the level of groups of neurons and interactions of groups of neurons than at the level of molecules themselves. Well worth exploring further ... and yes, important that knowing more about the nervous system in relation to behavior gives one avenues by which to explore. PG


Name: Doug
Username: dholt
Subject: action potentials
Date: Mon Feb 9 16:25:57 EST 1998
Comments:
I have to admit that i find the discussion regarding the use of action potentials as a method of explaining the basis of the nervous system very reassuring. I am pleased that we are trying to establish a base from which we can expand to more complex topics. The interesting parts of the lecture were definitely focused more on the rise of spontaneous action potentials leading to medical conditions such as epilepsy and basic autonomic functions such as pacemaker cells.

Regrettably, what I am failing to grasp is a clear concept of the bigger picture. While on one level the explanation is worthwhile for the basic understanding of how the body works, I have not been able to make the conceptual leap as to how the conscious brain controls the body. An autonomic feedback loop where the neurons are able to "sense" changes in the environment which in turn stimulates another neuron to innervate a target makes sense. But the question that still remains in my mind is along the lines of memory. How does the brain remember concepts and pictures? How are they assimilated so that ideas can be formulated from all of the memories in the mind? Why are memories of childhood able to be triggered when in the presence of certain smells or sounds, and why else aren't they easily accessible? It is amazing to me that there are people in the world who make incredible "conceptual leaps" that they describe as intuitively obvious. What is intuition? I have seen its expression, but why is it different in one individual than in another? How does your brain continue to work on solutions when you divert your attention to other things (or even go to sleep?).

The role of the brain as the processing unit of a body machine is a wonderful explanation that definitely clears up a lot of the questions that I had earlier in the class.. I would really enjoy delving into how thoughts spontaneously arise.

I appreciate both your understanding and your impatience. Indeed, we need a base, "from which we can expand to more complex topics". And the issue is not only to develop some tools needed to approach such topics but also to reach some understandings without which I don't think we can even adequately define the topics. To put it differently, one's intuitions about the meaning of such things as "intuition" need to be dissected a bit before the extent of the problem is clear. So bear with us and we'll see if we can get some of the things you're interested in sufficiently dissected (by looking at simpler things they aren't) so that we can talk about them effectively. That make any sense? If not now, AND not at the end of the course, be sure and let me know. PG


Name: Emma Christensen
Username: echriste@brynmawr.edu
Subject:
Date: Mon Feb 9 16:37:24 EST 1998
Comments:
I think that an understanding of the minute and minuscule functionings of the nervous system is vital when approaching the question of whether or not the brain equals behavior or even simply when approaching any question dealing with the nervous system. Without this understanding of neurons and action potentials, our perceptions and ideas of the nervous system gets hazy and often these complex processes fall into the realm of magic. I will admit unashamed that before learning about how the nervous system functions on this microscopic level, I had this foggy idea that there was this little ball of energy that kind of bounced around from neuron to neuron until it ended up in the brain somewhere and caused something to happen. It is _TERRIBLY_ important to understand these processes intrinsically before attempting to understand any of the larger ones of which the smaller processes are a part. Imagine trying to figure out how depression or schizophrenia are caused without completely understanding neurotransmitters and their complete function in the scheme of the neuron and action potential. No wonder people used to assume that people with psychological disorders were possessed by demons!--without this understanding of action potentials, what other explanation is there?

I'm being less than brilliant this week, so this will have to do, mes amis. I'll work on coaching my neurons to operate in a pattern more conducive to brilliancy this week...

I'll look forward to next weeek, but in the meanwhile, you're doing fine. You, of course, are not the only one who had a foggy idea of little energy balls (or some equivalent). And it is to avoid such "magic" that it is indeed important to get straight what neurons can do, and what they can't. Yes, of course, demons made a lot of sense until ... neurons came along. PG


Name: Ruchi Rohatgi
Username: rrohatgi@brynmawr.edu
Subject: brain=behavior?
Date: Mon Feb 9 16:40:08 EST 1998
Comments:
Understanding some more about brain function on a cellular level in a way did emphasize that brain equals behavior. However it is still difficult to imagine that the basis of ones behavior is actually the movement of charged ions across a permeable membrane and how such complex behaviors are based on the action of certain chemical/receptor interactions. Last week i commented how I believed that the "I" function which encompasses the "self" was responsible for motivated behavior. However, after pondering the issue some more, i kept thinking how in fact the brain produces self motivated behavior- behavior that one wishes to do or does puposefully. I understand the concept of how certain behaviors can happen without an input, such as an instintual behavior, but it seems that motivated behaviors are even more complex. I still cannot quite see how the actual thought process of doing something willingly translates into the neurons "talking " to one another and the consequent depolarization of the membrane and the resulting behavior produced... The fact that the brain is involved in an inhibition system with the spinal cord implicates their relationship working together in behavior more strongly. However, exploring the brain on a more cellular level lends more evidence of the brain actually equally behavior. When one initially said that the brain is behavior, it was difficult to conceive of an organ directly controlling ones behavior as an external response. How could something inside the body make us actually do/carry out behavior? i had argued initially that the brain was only the generator or originator of behavior. However, after learning more abut the signalling methods used by neurons and how motor neurons synapsed on muscles, it made a little more sense how the brain could direct behavior. However, I still find it difficult to conceive of the actual mechanisms involved in the translation between thought and behavior- i guess there are still some gaps to be filled before brain= behavior could be understood.

Nice set of issues, very much in the spirit of the course. Yes, indeed, this now makes more sense, but if that then what about THIS? Yes, talking about neurons and their spontaneous activity certainly makes it easier to understand that a behavior might appear without an external cause and that is PART of what we mean by "voluntary" or "self-motivated" behavior. But there is something additional in that idea which spontaneous activity in neurons doesn't seem to help one understand. Another level of complexity, as you say. So, now we have the problem straight. Think we can solve it? PG


Name: Bonnie Kimmel
Username: bkimmel@brynmawr.edu
Subject: patchwork of thoughts...
Date: Mon Feb 9 18:31:22 EST 1998
Comments:

What we have learned about action and membrane potential has definitely altered how I think about brain=behavior. It provides a critical foundation on which larger questions can now be explored. Why does a spontaneous potential happen? Do we think of these only in terms of certain homeostatic or vegetative functions, such as heart beat? Or can we apply this to all thoughts, memory, and intuition? If we know that certain behaviors happen because they are allowed to, what behaviors (emotional vs. physical) might be inhibited in all of us? How do things that once happened freely later become inhibited, and why? Are there scenarios in which we have no free will?

There was an article in Newsweek last month that talked about the neurotransmitter serotonin. The byline read "Could a single brain chemical hold the key to happiness, high social status, and a nice, flat stomach?" Clinical trials showed that individuals who had achieved a high rank within a group's social hierarchy had higher levels of serotonin in their blood than individuals at lower ranks. But it also makes the claim that "social standing has as much effect on serotonin as serotonin had on status." If we know that a chemical can have such huge effects on mood, such as depression and anxiety, and habits, such as obsessive compulsive disorder "possibly by overstimulating the receptors involved in planning and vigilance", why couldn't it apply to everything we do, think, and feel? Namely, all our behavior? This week's lecture, and this article in particular, made me think a lot about the use of drugs in therapy, and in what a vast range of scenarios it might be helpful or necessary.

Even if we knew the exact correlation between every permutation of brain chemicals and behavior we could not predict what course a life would take. So while I am definitely embracing much of the brain=behavior argument at this point, I'm still not entirely clear on how this affects, and is in turn affected by, other things such as our genes and experiences.

Nice set of connections. Yes, indeed, the next questions are do some of the principles we get from neurons apply generally? Only "vegatative" functions or "thoughts, memories, intuition"? Because, as you say, there are indeed aspects of those things which it seems DO have properties like those of neurons. And other aspects which don't? So let's start putting the neurons together and see whether we can get the additional aspects? Drugs as therapy, more generally as behavior modifiers are a very interesting and very general aspect of this question. As is, in the last analysis, would we, tracking this line of thought, find ourself doing away with free will? Or instead, perhaps, come up with a firmer base for asserting its existence (with all the attendent personal joys and responsibilities)? We won't, at least, ignore the issue, I promise. PG


Name: Jen
Username: jsabo@brynmawr.edu
Subject: Biology and Behavior
Date: Mon Feb 9 18:55:55 EST 1998
Comments:
Even though I now have a better understanding of what goes on inside our brains, I still don't know why we do certain things or act certain ways. I think brain is behavior, but there is something deeper that we just can't explain. There are definitely outside sources that influence our behavior including spiritual ones. I have so many questions, but i need to know a lot more about the chemistry of the brain before I can begin to pose these questions.

It is comforting to know there is a biological explanation for most things, but it can also be frustrating. Some things will always remain a mystery.

Most assuredly so if one doesn't specify them so they can be further explored. Give us some examples of what is mysterious, and why you think it must inevitably remain so? PG


Name: Rupa Hiremath
Username: rhiremat
Subject: Not going to change
Date: Mon Feb 9 19:12:33 EST 1998
Comments:
Before taking this class, I pretty much knew "nothing" about membranes and receptors. I had certain views in regard to the brain=behavior issue beforehand. And after a few weeks of this class, I have learned quite a lot more about these membranes. Not a surprise at all, my views and perception toward the brain equalling behavior has not changed substantially. Why is this? Everything just seems to make sense. Even after learning the nitty gritty about membrane potentials and receptors, I am still going to believe things the way I want, perhaps even after the course is over. The reason why I am doing this is probably due to the fact that we humans are very much accustomed to making observations and drawing conclusions ALL THE TIME, whether it be in the classroom or out in the real world. That seems to be the way we think. And when it is time to analyze our own brain, it is quite likely that we will not give it the benefit of the doubt because sometimes, "we think we know more than our brains know."

Nice thought. People/brains ARE stubborn. What do you suppose that means in terms of neurons? What might "believing" be, in terms of neurons? And what is the relation between that and "making observations and drawing conclusions"? Certainly in terms of neurons taking a class is just "making observations", yes? From which one may draw whatever conclusion one likes? Or .... ? PG


Name: jenn snavely
Username: jsnavely@brynmawr
Subject: brain?
Date: Mon Feb 9 21:00:58 EST 1998
Comments:
wow i really was intriqued by peoples entries this week, especially the ones that mentioned the idea of love... i could not agree more with the idea that there must be something else other thatn synapses and batteries inside our brains... i just do not know what it is. I found it very interessting that scientists have found certain areas of the brain that effect what is known as our idea of love and how we respond to it. the idea that certain areas of the brain seem to play important roles in certain behaviors is amazing but i am however baffled at how similar all neuronal transmisions are in comparison to such a vast number of behaviors. I think it is wonderfull to understand the way my neurons are working as i sit and write this entry but i also feel very cheated at the lack of explanation for all of my different behaviors. How is it possible that electrical impulses that happen basically the same way in all areas can produce millions of behaviors? To me it seems that it can not. but i am no scientists so who am i to say. I was also intrigued by the idea that behavior is "allowed" to happen. while i know there is much evidence about this i do think that we as humans have more control over our behavior than this qoute makes us out to have. I do not choose to see the brain as the master of my body simply letting me do things, it may guide me in a certain way but i do not think it controls me. Maybe that is my problem with the brain equalling behavior. this makes us out to be machines at the mercy of our brains and i just do not like that idea. while discussion on neurons and synapses, batteries and action potentials provides great evidence that the brain equalls behavior there must be more...i just hope i can figure out what it is.

And tell us when you do, please? Lots in here, might help to take it apart a bit, focus piece by piece. Yes, an important conclusion is that there is no explanation of all those different behaviors in the individual neurons or the signals they use since, in an important sense, those are all pretty much the same. Which means that an explanation for the large number of different behaviors probably has to be found in groups of neurons rather than in individual ones and, fortunately, the properties are such that one can combine neurons in different ways and get lots of different groups. The "allowed to" is interesting, indeed, and may help understand some things, but not others (not being a "machine"?). So, what kinds of organization might one imagine that would help make sense of that? Just because something is all neurons, does it have to act like a "machine", in the sense that we use that term based on machines we know (and have made ourselves)?, or is it possible that machines we have so far built aren't as elaborate as .... the machines that we are? PG


Name: Donald Ball
Username: dball@brynmawr.edu
Subject: Experience
Date: Mon Feb 9 21:28:50 EST 1998
Comments:
I am certain that my understanding of the brain and behavior has been broadened and enhanced by the information that has been presented. Yet, with each piece of information that is added to the picture I find that several more questions that beg to be asked and answered arise. In particular, I wonder how our new understanding of signal transmission might begin to account for the qualities of memory, intuition, and thought.

Signals are conducted about the nervous system in part due to the concentration gradient, and variable membrane permeability that exists at a certain time and place along a particular neuron. The type and quality of such signals, has a great deal to do with their mode of transnmission (chemical or electrical) and the kind of neuron they are travelling within (channel diversity). All of this can be used to explain a great deal. For example, motor neurons transmit via electrical currents because they can travel faster along myelinated axon sheaths than can signals along chemical pathways. Thus, we have a good chance of blocking a punch thrown by the third grade bully. Furthermore, chemical transmission allows for the modification or modulation of the signal such that the receiving neuron is 'flexible' in its response. The chemical intermediary, the neurotransmitter released when the presynaptic electrical signal reaches the presynaptic terminal, can vary. The post-synaptic terminal also varies in that the nature, properties, and number of the proteins embedded in its membrane are any of mnay possibilities. Thus, the range of possible responses to a signal is tremendous. This range of difference in response allows the nervous system to adjust over time, through repeated experience of similar imputs. It has been posited that this is the means by which we learn, and store that which is learned. So, now through practice we can not only avert the impending fist of our nemesis but respond with our own devestating blow.

All of this is wonderful, and indeed begins to explain how our genetic template can begin to be crafted by experience(re: Jeremy's essay) but, of course there has to be a but, what about the big picture? I am with Doug on this one. How are these responses to typical external stimuli stored? Where does the question of choice come into play? What about intuition - that nebulous gut feeling we have that often motivates behavioral choice? What is it about my DNA, thrust into the environmental contexts through which I have lived, that has allowed me to become the 'person' (the brain?) that I am? The questions go on...

I know that we don't have the ultimate answers to these but in a way that is the point. Behavior is a conflagration, a crazy multitude of possibility that evades compartmentalization. I like where we are going but science has never really been great at dealing with the abstract intangibles of life.

I'm inclined to agree with you about science and the "abstract intangibles", but also perhaps inclined to be more optimistic about science's prospects than you. Perhaps, like evolution, its necessary to make easier steps before it becomes possible to make more difficult ones? And the "abstract intangibles", the big picture, is part of the latter? The wherewithal to better understand "conflagrations" and similar complex systems is beginning to come into being, in part because some scientists, like you, recognize existing limitations in understanding, and in part because better understanding the details has brought into existence tools which weren't earlier available. As for the specifics, "memory", "intuition", "choice", "who one is and how one got to be that way" ... we'll at least take a crack at them all. PG


Name: rob miller
Username: rmmiller
Subject: Nothing but questions
Date: Mon Feb 9 22:14:52 EST 1998
Comments:
The discussion this week regarding the transmission of signals along and between neurons was particularly interesting. A most thought provoking idea was how signals could originate from nowhere inside the nervous system, triggered by areas of high sodium permeability. This concept helps explain much about behavior and how the brain works. Several examples of neurological disorders were discussed, and it is possible that these disorders may have originated from inside the brain, not from stimuli from outside the nervous system. It is possible now to consider some aspects of behavior originating from certain boxes inside the brain without stimuli. This is a useful concept, however, I am concerned that it will be used to explain many things for which no other explanation can be found. It is almost like an all-purpose excuse. If we can't figure out some aspect of behavior, we can simple say, Oh well it must have come from inside the brain. Simply stating that the brain can produce behavior from nowhere is helpful, but it brings up more questions about the bigger picture of the brain. Are these signals which originate inside the brain what create imagination and originality. Do they make people unique, or simply control bodily functions. What about thought and memory? Do the spontaneous firing of neurons triggered by no stimuli, which cause us to remember events which happened in the past. I need some help with these questions.

I believe it is important to understand the mechanisms which create neurological activity. It serves as a base to understanding more complex questions. My feeling however is that we may never get around to answering all of the questions which bother me this semester. Even worse is that more questions come up every week.

Even worse? An interesting issue. For a professional scientist, one of the keys to "tasting" a successful line of research is that it "opens up", creating new questions. So I, at least, will take your feeling as suggesting a promising start for the course. So long as the questions are new ones, instead of the same old ones. Yes, we don't want to get into "all purpose excuses" with things originating inside the nervous system. But yes, I think the ones we have will, non-magically, help us with much more than "bodily functions". PG


Name: Christine (Chris) Lord
Username: clord@brynmawr.edu
Subject: Inhibition causation
Date: Mon Feb 9 22:15:36 EST 1998
Comments:
The topic that really caught my attention was the idea that our cells firing was mediated by inhibition. Not that it was activation that caused what I call my behavior. I always had thought of behavior as being, think then act. If everything is controlled by inhibition, then it doesn't necessarily work that way. This explanation allows for a non-thought based action to occur. Let me explain. If I am walking down the street and my right arm suddenly flies up above my head instead of swinging naturally. I now have a way to explain that without saying "I wanted my arm to fly up, and didn't realize it." The Freudian in me is recoiling in horror at this idea. By realizing that what we do might be because of something as simple as a failure to inhibit, no actual intent, it makes me wonder about things that I do. In the most simplistic sense, muscle contractions etc, this is not a big deal, but in issues of interactions and so-called Freudian slips, an idea like this could cause major problems. Do we have motivations or uninhibited action potentials firing? Just something that struck me as I sat in class listening.

Appropriately so. Indeed one might wonder if some of one's behavior (a lot of it) is not only not caused by something outside but doesn't follow the "think then act" process either (though we'll have to say more about what that means, and will, in thinking more about the "I-function"). And that really shouldn't bother the Freudian in you. The message there, after all, was that some of one's own behaviors occur without one being aware of their causes (an "I-function" activity?), and that it is helpful (why?) to better understand such causes. So neurobiology is perfectly in line with Freud, no? PG


Name: Anuja Ogirala
Username: aogirala@brynmawr.edu
Subject: I-function
Date: Mon Feb 9 22:26:58 EST 1998
Comments:
The brain induces most behavior, however it is directed to do so by a self that is expressed through an I-function box residing within the brain. Where is this I-function box within the brain, this nucleus igniting neural activity? Maybe the entire brain is the I-function box. When do we lose consciousness of who we are? When individuals suffer from amnesia, they can lose some memories and can forget their names, but they don't lose their selves along with those experiences. The memories that they have forgotten have already made their lasting impression on their I-function boxes. Our selves are etched in our bodies, morphing and taking shape throughout the years without ever being damaged, lost or removed. You just can't forget who you are because it is in everything you do and the way by which you do it. A dead person and a brain dead person no longer have I-function boxes because they receive no inputs and can relay no outputs. In essence their sense of self can never be restored because without the brain's activities, without those neurons firing, there is no I-function box.

Even though the I-function can never be damaged, pathways from the I-function box to the myriad of neurons that are responsible for motor control can be damaged as we see in patients with Parkinson's disease. This damage to the brain's telephone wiring that leads from the self to the body's actions doesn't mean that Parkinson's patients are incapable of any desire to execute basic behaviors. They are merely incapable of directing their brain or muscles to do so. Somewhere the action potential gets incorporated by the wrong post-synaptic nerve or just dies out. The importance of observing neural activity is to determine how these messages should have been relayed from the NS to the muscles, and how these pathways can be manipulated so that communication can be restored. Each firing neuron has such a considerable, direct effect on the next neuron in its pathway leading to the intended behavior that the precision with which our unscathed neurons relay action potentials is surprisingly amazing.

Hmmmmm. Lots of assertions, particularly in that first paragraph. Maybe break things up a bit, develop more one at a time? All interesting though. We'll talk more about the I-function and the "self", but don't automatically assume they are the same thing because there are some observations which suggest otherwise. Along a related line, do you really want to assume that all activity is initiated in the I-function box? Maybe some starts outside that box? I like your discussion of connections from the "I-function" box to other places, and problems of interruption of those connections (sort of like the paraplegic, yes?), but why do you presume that the box itself can never be damaged?h PG


Name: vera barkas
Username: vbarkas
Subject: the question asked
Date: Mon Feb 9 22:30:50 EST 1998
Comments:
The cell is the basis of life. Cells are the building blocks of our entire body. Whether voluntary or involuntary, all actions, seen by us as one event was made possible by individual neurons working togther to produce that action. We have lust far learned about how neurons carry messages down their axons, and have only touched the surface of knowledge related to the neurvous system. Because behavior is such an essentail part of lives I think it is inportant for us to realize how our neurvous system works on the cellular level as well as from a pyscological and physiological standpoint. I am very biological minded person. I see everything in this world made possible by the workings of biology. I believe that our bodies are purely biological and therefore I hold knowledge of how our neurons work as more important than what our naked eyes observe about behavior. I guess this is where neurology must depart from the study of behavior. The former is purely biolgical and the latter is more pyscological. I wish i already knew the basic stuff about neurons so that I could understand how the nervous system works as a whole. I do care why we do some of the actions we do and what causes them from a psycological standpoint, but I believe it is important to learn how the biological aspect of this study is organized before we tackle the larger picture.

Fair enough. But why do you believe these things, what inclines you to be a "biological minded person"? And what do you see as the distinction between biological and psychological? and why is the former needed for the latter? PG


Name: Elizabeth Windsor
Username: ewindsor
Subject: perceptions of reality
Date: Mon Feb 9 22:36:45 EST 1998
Comments:
A better understanding of how the nervous system works has affected the way I think about behavior. In particular, I did not know that there is nothing in a particular signal that characterizes sound (for example) as opposed to light or action. I had never thought of the possibility of seeing thunder or hearing lightning.

Because the interpretation of a signal is mainly dependent on the specific neurons that are carrying the signal, if the signal deviated from the "normal" pattern of neurons we might actually be able to see thunder. I don't know how plausible this is in real life, so the rest of my comments might be irrelevant. Even if it isn't plausible, it still points to the link between perceptions of reality and behavior.

A lot of behavior that is linked to the I-function is heavily influenced bu reality as it is percieved. If I really believe everyone else is out to get me, then I will act in accordance with my belief. Most other people would then accuse me of exhibiting abnormal behavior because they do not believe that anyone is out to get me. It is abnormal because I am reacting to a view of reality which most people would not share. This can be seen in people who have low self images. If their perception of themselves becomes increasingly positive, there will probably be a corresponding increase in changes of behavior.

But what about views of reality that we expect to be more concrete than self image? What if I covered my ears every time bright light shone in my face, or I closed my eyes every time I heard a loud sound? My eyes and ears would suffer damage due to the fact that they were not protected from the real dangers. I would hope that I would eventually figure out that there was a problem. But it is possible I might not, especially if a lot of other people also suffered from the same problem. We might just believe that our eyes and ears were supposed to fail us early in life. I don't actually believe in a sixth sense, but following along with this line of thinking, you never know.

This brings up the point that a proper understanding of reality is greatly to our advantage. At the same time, however, it points out that we are incapable of discerning what the "real" reality is.

Very well said: there is indeed a quandry there. And you've even given some of the ways of dealing with, by exclusion. Yes, we believe we have a sense of reality because we test it ourselves as well as by comparing it with what other people say. At the same time, people DO see things differently, as we'll talk about more later in the course. PG


Name: Alicia
Username: aebbitt
Subject: Nervous System, Structure and Function
Date: Mon Feb 9 23:08:10 EST 1998
Comments:
I was not terribly excited about this week's essay question, but am quite pleased with the deeper understanding I am gaining about the way the nervous system functions. In the first week of class, it was all fine and dandy to say that brain=behavior, but now I am actually beginning to understand how this is possible. I find it extremely interesting that there are certain spontaneous action potentials being produced in our systems. For me this helps to explain certain instinctive actions and things that sometimes I do, but don't know why I do them. I also feel that a better understanding of the nervous helps us to develop a better understanding of certain disorders and the behaviors that the accompanies them such as Terret's Syndrome.(I apologize if I spelled that incorrectly) The repsonses that many people have a result of Terret's Syndrome are small seizures that go on in their systems. I find it quite interesting to learn that this action is in fact being "allowed" to happen rather than a response to some sort of stimuli. My question is why in patient's with diseases such as Terret's and epilepsy is the brain unable to function correctly and stop these actions from happening? What has "gone wrong" in the nervous system to "allow" these actions to take place?

Tourette's Syndrome is indeed a very interesting connection from things we talked about (don't worry about the spelling, I had to look it up). And there isn't a general answer to your question, in the sense of one thing that accounts for all examples of things being "allowed" rather than "caused". In general, though, one might guess that there are two broad classes of explanation: membrane permeabilities which lead to spontaneous firing or an absence of inhibition which normally holds spontaneous firing in check. Looking around on the web in one or another situation to see which holds might make an interesting web project. There are some additional subtleties to be aware of, though. Both epilepsy and Tourette's may show some context dependence, i.e. "attacks" more frequent in some sensory environments than in others. Can you fit that into your picture? PG


Name: Miriam Kulkarni
Username: mkulkarn
Subject:
Date: Mon Feb 9 23:44:35 EST 1998
Comments:
In my psychopharmacology class, we are learning about neurons' ability to upgrade and downgrade the amount of receptors for a given neurotransmitter in response to changes in the amount of neurotransmitter availible. When excessive levels of a neurotrasmitter are present, neurons downregulate so that there are fewer receptors for that neurotransmitter, and the receptors are less sensitive. When levels of a neurotransmitter, such as dopamine, are very low, neurons upregulate so that there are more receptors for that neurotransmitter and the receptors are more sensitive. This regulation of receptors can compensate for a great deal of change in the brain.

This concept intrigues me, because it implies that constant levels of neurotransmitters in the brain are needed for normal functioning. Indeed, abnormal levels of dopamine are believed to be involved in both Parkinson's disease and schizophrenia. It seems to me that the amount of a neurotransmitter bound to receptors does not depend on interaction with the environment but instead is relatively constant. Before I was introduced to this concept, I thought neurotrasmitters simply linked neurons together, relaying inputs and outputs from one area of the nervous system to another, constantly changing in response to the environment. Now I see the brain as very constant; even small changes in the amount of neurotransmitter availible are compenstated for by changes in its receptors. When levels of neurotransmitter do change drastically,as in schizophrenia, a individual's whole personality can change, although there is no change in his environment. I am beginning to believe that we are our neurotransmitters; that it is levels of chemicals in our brains, more than any of the experiences of our lives that make us who we are.

p.s Please forgive me if my explanation above is unclear. I found the concept a rather difficult one to explain.

No problem, you've done well, and the issue of internal regulation of both transmitters and transmitter sensitivity is an important and relevant one (though not one we'll spend much time on in THIS course). Who we are is certainly in part a function of transmitter levels and sensitivities, but don't overstate the case. Transmitter levels and sensitivities are to some extent internally regulated but they are also influenced by the environment. And, in the last analysis, its the patterns of activity in neural networks rather than the transmitters themselves (which influence them), which are probably "who we are". PG


Name: Jonathan Ball
Username: jball@haverford.edu
Subject: The Nervous System
Date: Tue Feb 10 00:40:42 EST 1998
Comments:
Understanding behavior is similar to understanding weather; you can begin to learn trends, but you can never fully understand or predict it because there are and infinite number of variables that may be affecting it at any given moment. So to gain a better understanding of behavior it is necessary to understand as many of the variables affecting it as possible. And one of the most important variables that needs to be studied in any attempt to understand behavior is the functioning of the nervous system. There has been a lot of argument already this semester as to whether the brain=behavior, but there has been almost no argument that the nervous system contributes to behavior. The evidence is all around us, from simply feeling listless and tired when we haven't eaten in awhile to changes in the way we thought about other people as the levels of certain hormones changed, the functioning of our nervous system alters our behavior and therefore is an important area of investigation.

While I do feel that the nervous system is an essential part of behavior, I still am not comfortable accepting the statement the brain=behavior. Without an environment in which to exists the nervous system would not be able to function and therefore there could be no behavior, so I still believe that the interplay between external and internal (the nervous system) environments, is the cause of what we call behavior.

I'm content with behavior as a brain/environment interaction, except for one thing which we'll get to as we proceed: it is demonstrably so that the nervous system will continue "doing its own thing" when totally isolated from the environment (for an advance look see Figure 2 of Variability in Brain Function and Behavior). And, of course, the environment has its effects only in so far as it produces action potentials in the nervous system. I agree that for a better understanding of behavior, "it is necessary to understand as many of the variables affecting it as possible". But it seems to me that calling the nervous system simply one of those many variables is seriously underestimating the centrality of the nervous system and its effective identity with behavior. Needless to say, we should touch base on this again and again as the course goes on. PG


Name: Moriah McSharry McGrath
Username: mmcgrath@haverford.edu
Subject:
Date: Tue Feb 10 02:00:38 EST 1998
Comments:
I'm interested in Karen's questions about behaviors like crying, which seem to bear no evolutionary advantage. In fact, it seems like such a behavior, in which an individual's emotions preoccupy him/her so much that he/she might be distracted from self-protective behaviors, might even be disadvantageous.

Also, I wonder what the evolutionary motivation for hormonal influence on emotional behavior is. This is definitely perceived to be more of an issue for women, who have a relatively well-understood hormonal cycle: everyone has heard about how weepy premenstrual women are supposed to be and what strange cravings pregnant women are supposed to have. Though I believe that these phenomena are often overstated, it has been documented that hormones have a strong effect on emotional state. I guess I wonder first of all what the biological benefit of these emotions is and, secondly, how hormones enhance this. Furthermore, why do we hesitate to examine this relationship in men?

It should certainly be examined more extensively in men and, as we'll talk about later in the course, there is good evidence for internally generated mood variations in all humans, irrespective of sex. We'll talk too a bit about what the advantages of mood variations might be. Interesting and relevant issues. "Evolutionary advantage", though, is a slippery concept, as has been discussed on and off earlier in these exchanges. James Gould, an evolutionary biologist, has written about this slipperiness extensively. PG


Name: Akino Irene Yamashita
Username: ayamashi@brynmawr.edu
Subject: genetic determinants of behavior, ex: falling in love
Date: Tue Feb 10 10:03:40 EST 1998
Comments:
I don't have much to say about the original suggested topic, except that it was very interesting how a genetically-controlled mechanism exists for spontaneous behavior. And I think a link can easily be made between genes and how the genes influence the development of the NS, especially since the increased permeability of Na channels depends on the presense of certain proteins, and DNA and RNA directs the synthesis of proteins.

Also, I was intrigued by how in some cases the NS does not actively cause a certain behavior but rather actively inhibits itself from allowing that behavior to happen. I did not know until last week that chickens actually do run around when their heads are cut off! I had once seen on a Nature TV show, or maybe it was Discovery, how a female praying mantis will bite off the male's head during mating and how this enhances his "performance". And I had always wondered how that was possible, but I guess the "suppression theory" now offers an explanation.

I hate to sound like the moralist on this forum, but the comments some people have made about attraction and love-- well, they do not exactly disturb me, but they make me wonder. I once read an article about how, despite the protestations of many of us, attractive people do receive much better treatment, not only in terms of romantic involvement but in things such as the kind of service they receive in stores and restaurants. That article said that people seem to link attractiveness to symmetry, and said that the face of Denzel Washington, who most would consider very attractive, is almost perfectly symmetrical.

I guess what actually disturbed me was someone saying how, for example, large breasts are usually a signal that a woman can nurture children very well and this explains why boys are attracted to them, if this is how they are genetically "wired" to behave. Well, maybe this is more the age-old "nature vs. nurture" topic, and I am going off topic slightly. But it seems such information could justify shallow behavior and double standards that I think most people try to overcome through education. After all, if it's genetically determined that men want voluptuous women, or that women want providers with money to take care of their children, why fight it? But it seems that if these genetically-controlled tendecies are followed through on completely, this would mean that many good and decent people would be left out in the cold in the dating game. Or maybe I am being too idealistic here.

Also, assuming that most people try to overcome such animal natures; I know that some studies have shown that the brains of men and women function differently. Well, if some behavior differences (probably not all) between men and women are due to biological factors, would this in itself justify different standards of behavior for men and women? Since I am sure some would argue precisely that, that treating men and women differently is not discriminatory because men and women are different.. On the other hand, this is what some people used to say about white people and black people, and maybe still say -- remember The Bell Curve? I guess the larger question is, should the fact that a behavior is determined by genetic factors be in itself a justification for such behavior?

Also, someone referred to how it was purely evolution that had shaped the development of the NS. But as I learn more and more about the complexity of organisms, especially the NS, I can't help thinking that the mind-boggling complexities I encounter didn't develop purely by chance. I can't help thinking that there was a Designer, a Creator, who somehow guided the process of evolution. And if that is true then the fact that behavior is purely due to the many biochemical processes in the NS doesn't diminish the significance and meaningfulness of behavior.

Lots of interesting issues. To start, you are of course correct that since permeability depends on proteins, genes influence the nervous system (and hence behavior if ...). The operative point is "influence", as opposed to "determine", and I don't think you're being too idealistic: genetic influences should NEVER be confused with "determinants" and used as an excuse for anything. It is indeed the business of education (and culture and parenting and ...) to give people the wherewithal to behave in ways they might not have otherwise (an interesting definition of "animal nature"?). All of which of course bears on any kind of genetic difference, including males/females, blacks/whites, and so forth. Genes don't "determine" behavior, they, among other things "influence" it. There are some more thoughts on the Bell Curve , and other related matters, in Serendip's section on Genes and Behavior. PG


Name: Neha Navsaria
Username: nnavsari@brynmawr.edu
Subject: weekly essay 4
Date: Tue Feb 10 11:03:37 EST 1998
Comments:
I feel that learning about such cell level processes as action potentials and membrane potentials is just the beginning of the understanding how one thinks about behavior. What we have learned in class so far is a very simplified model of just one neuron interacting with another neuron. Seeing one neuron interact with another cannot tell us much about behavior, but it is a start. Once we learn about specific behaviors then our background in cell level processes that we have learned will help us account for those behaviors. Also, in my opinion learning about abnormalities in cell level processes (or any other processes in general) helps to understand abnormal and normal behavior.

The idea of the combination of inhibition and spontaneous activity was an important concept that I never had heard of and that helped explained some of the underlying causes of behavior patterns.

Glad you liked it. Want to be more specific about behaviors which it might help to understand? Yes, of course, we can't do much with just one or two neurons, but the background on cells will be useful. Any guesses on why, and what the limitations might turn out to be, if any? PG


Name: ruth czarnecki
Username: rczarnec@brynmawr.edu
Subject: ideas about behavior
Date: Tue Feb 10 13:42:46 EST 1998
Comments:
The question posed this week deals with whether or not a deeper understanding of the mechanics of the nervous system change ideas about behavior. Another form of this question, that I thought of immediately, is, does the microscopic form of the nervous system (the concentration gradients and particles) change the macroscopic form (behavior). My answer is that I don't neccessarily think so.

Granted, on a small scale, things are changed, some become more important, some become less, but the overall effect does not neccessarily change. What types of behavior occur depend entirely upon what occurs in the axons and dendrites and synapses of the individual cells, but knowing that it is just a bunch of ions moving in and out of equilibrium does not change the fact that you swung that bat to hit the ball, or fell in love at that moment, or cried necause someone told you that your grandmother died. Of course, a small change in the way that the ions moved could make you miss the ball, or not fall in love, or just stay shocked, but would that be a failure on the microscopic part, or just a different behavior? And would the behavior chosen vary as to the person, most certainly. If one person is rather poor at baseball, they will miss the ball more often than not, a better player would hit it more often. I do not believe that knowing what happens on every level, changes the outlook on behavior, it only explains some of the mechanics.

Hmmmm. My sense is that there is somewhat more subtlety in your arguments than is fully reflected in your conclusion. You suggest a very interesting way to approach the problem: would changes in cellular and subcellular properties change what is observed at the behavioral level? The answer is sometimes dramatically, sometimes very little. Which is to say, there is not in general a DIRECT relation between lower level and higher level properties, for interesting reasons which it would be worth trying to specify more carefully. On the other hand, SOME things that are mysterious at the higher level can be made more sense of by appealing to "the mechanics". Maybe indeed some of why I was always a poor baseball player has explanations other than "failure to concentrate", "not willing to work hard enough", and the like? That would make me feel a little better about it. PG


Name: Daniel Casasanto
Username: dcasasan@brynmaw.edu
Subject: Weekly Essay #3
Date: Tue Feb 10 14:21:39 EST 1998
Comments:

C.G. Jung proposes an individual human psyche composed of paired opposites: chiefly, the conscious ego, and the unconscious shadow which, for better or worse, opposes whatever attitude the conscious ego asserts. Jung suggests that each "soul-image" comprises both anima and animus, meaning not that the person is both male and female, but that the soul is at once masculine and feminine.

The sciences echo Jung's suggestion that natural phenomena can be described as both unity and duality at the same time. (Niels Bohr fashioned a coat of arms for himself which bears the motto, "Contraria Sunt Complementa," and which features a Yin-Yang symbol in the center of the crest, alluding to the Eastern philosophies that have embraced this paradox for centuries.) Physics describes light as being simultaneously particle and wave, and shows how it behaves as both. Physicists both distinguish between and concorporate matter and energy, time and space. The idea that paired opposites compose the whole is central to our understanding of the atom. The newest Physics suggests that the oppositely-charged nucleons formerly believed to be fundamental are composed of an even more minute pair of particles, and that both of these particles are, in fact, composed of the same basic material: that the fundamental opposites are actually different vibrations of the same "string." Chemistry provides the imperfect model of resonance structures, which help us to conceive how a molecule can be instantaneously the same and different. Biology tells a story of continual anabolism and catabolism, describing how life is a process of both overcoming entropy and succumbing to it.

In this class we seek to describe the dichotomy/unity of the body and mind. We have agreed that the brain, which gives rise to the mind, is matter which uses energy. We have also agreed that the integrated "signals" that compose the mind are neither matter nor energy. We have voiced arguments that show the mind and brain to be distinct, and arguments which show them to be synonymous. I'd like to suggest that both viewpoints are correct: that rather than trying to decide which one is right, we accept them both, and decide which description is most valid or useful in a given context. I think we need to get comfortable with this paradox; I am impatient to explore it, but I'm not anxious to resolve it.

Interesting, relevant issues/extensions. Let me add an additional extension to mull? The anabolism/catabolism distinction is, of course, an imposition of labels by the human brain on a system which itself makes no, and in some ways has no, such distinction. Molecular resonance, at least in some ways, is a concept developed to update older ways of understanding molecules which no longer proved entirely adequate. The same is, of course, true of the equivalence of matter and energy, and of space and time. All of which is to say that "dualities" themselves may be more a product of the human brain's effort to make sense of things than they are a genuine property of whatever one is trying to make sense of. That, of course, raises an interesting question about the brain: what aspects of its function predispose it to seeing dualities? It also makes it at least possible that "dualities" are simply a common transient phase in the history (past or future) of trying to make sense of things. So maybe brain=mind is the next phase in this particular case? Are there really compelling arguments for keeping them distinct? PG


Name: Mindy B.
Username: mboyce20@aol.com
Subject:
Date: Tue Feb 10 17:08:06 EST 1998
Comments:
I would like to address Dena's comment on the genetic predispositon to find certain characteristics attractive (such as large breasts-- which makes it impossible to explain the Kate Moss waif phenomenon). While it may be true that a genetic component may be responsible for making us somewhat predisposed to certain traits, I would argue that it is our experience which primarily (or at least equally) determines what/who we are attracted to (no reference to bestiality- I meant aesthetics). Genetics/physiology may account for the basic consensus among people as to beauty (such as the appreciation of symmetry Akino mentioned) but experience and environment may more profoundly affect our notions of what is attractive (one of the best examples was mentioned in class- different cultural notions of beauty). I would also venture to say that while it helps determine what we find attractive, experience is even more responsible for determining whom we "love." Love, in my estimation, transcends mere visual attraction and involves an attraction to a person's patterns of behaviors as well as their other outward characteristics (the way they feel, smell etc). Often a person is attracted to someone who shares their interests, is similar to or different from their parents, who shares their need for codependency, is of a similar educational background etc. All of these behaviors are determined or shaped by experiences not just genetics. Dr. grobstein provided part of the answer to how/why experience can totally shape behavior today. If you use the nervous system it changes. This explains how ones experience changes the filters through which sensory inputs travel, changing your reaction to them. If your experiences are different, you react differently. Does love transcend this? What does this say about the notion of a soulmate? Is there one person out there who is meant for you? I think it means that there is no single person who is "perfect" for you and it is a matter of meeting one of many people whose experiences and genetics make their behavior and physical characteristics match your genetics and experience-based behavior and physical characteristics.

Regardless of whether it is genetics or experience, I am stunned by how complex attraction really has to be. Think of how many neurons are receiving, processing and transmitting some type of message just to give you that queasy-stomach, rapid heart rate feeling. Each neuron involved is affected by the millions of inputs that have travelled across it in your lifetime. As to genetic determinations, proteins in many of the neurons are going to have to have a certain shape, one out of a myriad of possibilities. And this all has to work in combination. Of all the proteins of all the neurons of all the nervous systems in all the vertebrates with any of all the combinations of experiences in the world-- yours had to be compatible with mine!

Not only compatible with NOW, but, as you say, compatible with a process of generating an increasing match between etc and etc. Yep, pretty extraordinary, when you come right down to the neurobiology of it, which, of course, matches one's experience of it when it happens. Pretty good last word on the subject (though I suspect it won't be). PG


Name: zermatt scutt
Username: mscutt
Subject: What are we doing?
Date: Wed Feb 11 01:21:51 EST 1998
Comments:
Forgive me, but I'm still hung up on our first week's discussion from which arose the statement, "Brain is behavior...there isnít anything else". Seeing that speaking is a behavior. Every word or phrase or concept that I utter is a function of a "pattern of activity" in my brain. Isn't it then a bit troublesome that the statement, "Brain is behavior...there isn't anything else" is in itself a result of a "pattern of activity" of the speaker's brain? Does that have any bearing on the nature of the statement. When you "think" about it(another pattern of activity) this statement can be presented in two ways, either as an objective statement or a subjective statement. From the way it was stated in class, it was presented not merely as a subjective observation of the speakers's brain, but as an objective theoretical statement. It then appears to me that its assertion as an objective theoretical statement in itself assumes an objective reality outside the brain, thus falsifying itself.

Along the same line, a danger that I observe in the class lectures and discussions is the unstated acceptance of this theory as we continue in our effort to understand the nervous system. It appears to me that we are trying to make the data fit the theory by going ahead and trying to explain things such as the sense of self, love or feelings by the criteria of this theory, that brain is behavior...there isn't anything else. It is obvious that this theory works well on some behavior but leaves a lot of questions unanswered on other behaviors. My assertion would be that this model of Brain=Behavior, although it contains some true elements has been shown by the unanswered questions and issues raised in class to be lacking greatly. So instead of trying to make the observations fit into the model, why not venture to try a new model, a new model that better explains our observations. After all, that's what science is all about, seeing what's wrong with the proposed theories so that better ones can be formulated.

Yes, "thinking about" the brain can be usefully conceived as "a pattern of activity" in the thing which is itself the subject of the "thinking about". What's less clear to me is why you think that itself is a problem. Perhaps its the "objective" vs "subjective" issue? If so, we'll talk more about it after we've looked a bit at sensory systems and perception, since that will substantially blur the distinction between "objectivity" and "subjectivity". For the moment, I at least don't have any trouble with the idea that patterns of activity in the brain can equally well constitute hypotheses about both what is "out there" and about itself. As for "unstated acceptance", I certainly hope that's not what's going on (and don't think it is from much of the forum discussion). Brain=behavior is a model under consideration, and, for what its worth, its a NEW model in the context of human inquiry, one we're examining to see whether perhaps it does a better job of making sense of behavior than older models. The task is not "to make data fit" but instead to look closely and rigorously enough to be able to say with precision if something does not fit and exactly why. Yes, all models ultimately fail. That's the point of science. But its very hard to get to a better one without knowing exactly what is wrong with existing ones. As you say. So where are the unanswered questions, are they truly incompatible with brain=behavior, and why? That's what we're after. PG


Name: Rehema Trimiew
Username: rtrimiew@brynmawr.edu
Subject: The brain in C++
Date: Wed Feb 11 03:31:04 EST 1998
Comments:
The more that we learn about neurons and their capabilities, the simpler they appear to be. As we learn more and more it seems as if we could almost predict their "behaviour" and know what they would do in any situaion through simple mathematics. This reminds me of the play "Arcadia" in which Thomasina believes that through iterations she can discover the equation for everything (My memory is fuzzy, I think that's the gist of what Thomasina was trying to do). It seems as if we had a computer large enough to hold information for each neuron then we could predict every thought of the person it is modeled after. Of course, this is currently impossible, but it is interesting that some of the things that Thomasina sought were later discovered. Will the brain and behaviour be also?

Crickets or other creatures with smaller nervous systems don't have as many neurons as humans. Is it possible to program a computer to mimmic or behave as an actual cricket? If each neuron has a certain number of proteins in the membrane of a certain permeability, with an action potential of a certain amount then it seems possible. Except for emergence. We talked about emergence at the first TA session and though we might know all of the rules of "neuronal behaviour", we do not know all, how, or why various unexpected patterns arise. But, it seems as if the prediction of only one pattern would be enough for a pseudo-life form. Also, the signals that spontaneously arise in a neuron can not be accounted for.

PS. I have thought about this for a while. However, I am writing this at 2 in the morning, so please excuse some of the errors.

Don't froget to comment on this or my last one.

Yep, late but done, both of them. And I like you connection to Thomasina in Stoppard's Arcadia. Remember though that it was the slightly younger Thomasina who dreamed of an iterative rule that would account for everything, and a slightly older Thomasina who realized that "heat" precluded that. And one might (indeed we all) suggest that, as you say, its the spontaneously arising action potentials (among other things) which aren't in the equations and constitute the "heat". PG


Name: Kristin Chimes Bresnan
Username: kchimes
Subject: Information as a third thing
Date: Fri Feb 13 20:23:09 EST 1998
Comments:
One of the ideas which has most captured my imagination is the idea that information, not matter or energy, is what flows through our axons. I like very much the idea that information constitutes a kind of "third thing" in the universe, and the questions I have been asking myself all have to do with finding a way to characterize the storage and flow of information.

The two systems I have thought about are language; and the genetic code of DNA. What do they have in common?

1. a set of building blocks: our language uses both the alphabet of 26 letters, and a set of accepted sounds; DNA uses the four nucleotide bases read as non-overlapping triplets to code for the arrangement of 20 amino acids.

2. the reciprocal traits of stability and variable expression. Language is stable in two ways: through time over the course of generations, and in our own memories (for example, words do not change shape or meaning in our memories; they are stored there, ready for use as needed). It varies in the same ways: over time, language slowly changes its shape to adapt to changing environments (old English is different from middle English is different from modern English); and it varies in the way we use it in any given moment (the way we can arrange words is like a mathematical limit approaching infinity). The stability of DNA is in its architecture and in its base-pairing system, and in its mode of reproduction; its variability is in both its differential expression and in its mutability.

There are, I think, more and subtler ways in which DNA and language can be compared to each other. (What I haven't been able to decide is whether DNA is merely analogous to language, or if they can actually be grouped together as modes of information storage and transport.) If we allow for a few minutes the idea that they both might be different ways of doing similar things, then the nervous system is yet another way of doing these things. Would one say that its building blocks are axons, or ions and variable permeability, or transient charges, or neurotransmitters? Or the sum of these things? Are its stability and variability merely a result of its hard-wiring, so to speak? (anatomical specificity and responsiveness to particular stimuli).

One other thing which has influenced my thinking about all of this is a bit of an essay I came across, which described language as "transcending the machine of its own reproduction". What does this mean? It means that the motor neurons which tell our mouths to speak and the auditory neurons which record and translate that speech, as well as books, typewriters, recordings etc, are all parts of the machine of reproduction which convey and store language, but language itself "transcends the machine"; it is more than the sum of its parts. Is the same true of information, then? And doesn't the analogy also suggest that the "self" might also "transcend the machine"? That any system of storing and transporting information might, by virtue of what it does, have a "transcendent" component? Is this what it means to have information be a third component, next to matter and energy, of which the universe is made?

Very interesting, potentially very generative set of thoughts. I trust you'll take it as encouraging (as you should) rather than discouraging that the language/DNA parallel is one that has occurred to others as possibly fruitful to explore. I remember a paper written by a graduate student, Marty Sereno, when I was on the faculty at the University of Chicago. Sereno is currently on the faculty at University of California, San Diego and has on the web a sketch of some of his thoughts. Marty's home page gives the reference to a paper in the Journal of Theoretical Biology in 1991 that you might want to have a look at if you're inclined to think more along these lines.

There certainly are useful parallels in thinking about language and DNA. What intrigues me about both of them is that they are "generative", i.e. the symbols and rules of combination of symbols are such as to allow not a finite but an infinite number of possible combinations. And yes, I think there is an important sense in which language (and DNA) "transcends the machine", at least in the sense that the information contained in any given symbol sequence can be transcribed/translated into other media without changing the information. The same information can be represented, for example, in printed musical notation, in grooves in a record (or, these days, in pits in a CD), and in sound waves. It hadn't occurred to me to speak explicitly of the nervous system itself as an information representation, though that idea is certainly inherent in the way I think about it, and I want to explore that further. Thanks. I'm pleased you like the idea of information as an independently explorable entity. You might enjoy looking at an article I wrote which talks about that idea and what made it occur to me. In return, you want to tell me where the "bit of an essay" is? PG




| Course Home Page | Back to Brain and Behavior | Back to Serendip |

Send us your comments at Serendip
© by Serendip 1994- - Last Modified: Sunday, 15-Feb-1998 21:46:06 EST