Biology 202
Neurobiology and Behavior
Spring 2002

Forum Archive - Week 6

And a break point in the course, so ... what do you think? We started with brain=behavior and now know brain is neurons with ionic gradients, variable membrane permeabilities, and current flows, which respond to and release chemicals. Is that enough? to account for behavior, including experience? What would it take to get from where we are to that? Do you think we can do it?


Name:  Paul Grobstein
Username:  pgrobste@brynmawr.edu
Subject:  week 6
Date:  2002-03-01 23:00:48
Message Id:  1297
Comments:
First web papers, all received to date, are posted. An array of interesting stuff, so browse around. If you've sent yours and it isn't there, let me know.

And a break point in the course, so ... what do you think? We started with brain=behavior and now know brain is neurons with ionic gradients, variable membrane permeabilities, and current flows, which respond to and release chemicals. Is that enough? to account for behavior, including experience? What would it take to get from where we are to that? Do you think we can do it?


Name:  Kelli
Username:  rdeering@brynmawr.edu
Subject:  
Date:  2002-03-02 13:50:41
Message Id:  1299
Comments:
I feel that we have progressed quite a bit from our original, untested hypothesis that brain=behavior. It has been established that great variation is present due to assortment and arrangement of our basic nervous system unit, the neuron. A passive wave of membrane permeability explained the nature of the impulses needed to transmit information. Furthermore, the small numbers of motor neurons reinforce that the nervous system is less dependent on its environment than perhaps was initially assumed. The ability of neurons to generate action potentials without reliance on a stimulus also supports this idea.

However, the mechanisms for control present in the nervous system are quite sophisticated and help explain why organisms typically do not continuously experience random, involuntary movement and behavior. Inhibitory post-synaptic potentials and controlled release of neurotransmitters, in addition to the highly specialized and selective nature of all chemicals and processes involved, are some of the main functions needed to explain control.

The questions I am still interested in having answering include: how does that brain store information? How is this information accessed and used for further processing? I was in a car accident last semester and suffered a head injury associated with memory loss. I am still unable to recall certain events, peoples' faces/names; I cannot retain a lot of new information, etc. I suppose memory is particularly interesting to me because I would like to understand what processes were damaged, and how these functions normally work.


Name:  Rebecca Roth
Username:  rroth@brynmawr.edu
Subject:  Week 6
Date:  2002-03-02 14:45:02
Message Id:  1300
Comments:

Our brains are different from each other. Learning about how neurons are organized and their interaction can lead us to a better understanding of behavior. Neurons listen to a lot of different inputs. There are differences due to different connection patterns among neurons. Wouldnít the paths traveled have to make a difference in our own experience? There could be different experiences due to different connection patterns among neurons. Our own activity is constantly changing. The nervous system is being processed by these signals but, also being changed by those processed signals. Do the patterns of activity in neural networks determine the type of person we are?

I think it is amazing that you can still see movement in the body after a chicken's head has been cut off. Is there still thought going on about what is really being done and happening? The running around?

Brain equals behavior? Seastars are an interesting animal to look at. Afterall, their nervous system is very simple. They do not have a brain and there is no ganglia to coordinate movement. The nervous system consists of as a nerve ring that surrounds the mouth. A radial nerve branches off of the nerve ring and extends to each arm. Yet, donít starfish have some type/form of behavior? Can the same be said about jellyfish? Jellyfish are more than 95% water. They have no heart, bones, or brain, and have no real eyes. So, does brain really equal behavior?


Name:  Balpreet Bhogal
Username:  bbhogal@brynmawr.edu
Subject:  
Date:  2002-03-02 19:36:48
Message Id:  1303
Comments:
When we started this semester talking about the brain=behavior hypothesis, everything seemed so simple. We either agreed with the theory that brain=behavior, or we thought that there was something else that contributed to behavior (ex: perhaps the existence of a soul contributed to behavior, etc.). But it became more apparent that the brain and nervous system were more complicated than it appeared to be when we began discussing neurons. There are many aspects of the nervous system that are important for relaying signals to the brain. We have to consider ionic gradients, membrane permeabilities, current flows, chemical releases at synapses, etc.

Personally, I believe that there has to be something more that accounts for behavior. What we have discussed seems complicated enough, but it's only half way through the semester-there has to be something more! We haven't really discussed the idea of experiences and thought yet. Perhaps there is something more than what we have discussed that contributes to the that. Could we do it? I think we can. :)


Name:  Beverly Weiss
Username:  BBWeiss@aol.com
Subject:  Brain =Behavior
Date:  2002-03-04 10:25:46
Message Id:  1318
Comments:
Yes, I am still convinced that Brain=Behavior. Other components of this behavior mix are our genes and experiences, which alter and determine behavior and contribute to our uniqueness.
Given that action potentials can start mid-axon, and move forward to connect with other dendrites and ultimately result in the release of neurotransmitters into the synaptic cleft, (along with the whole mechanism of neurotransmitters binding to proteins....) we still have only the "computer-like" process of the neurons, responsible for all of the feelings and sensations that we experience. Even when our feelings are spiritual or mystical, they are still caused by chemicals which come from the brain.
Name:  Amy Cunningham
Username:  acunning@brynmawr.edu
Subject:  
Date:  2002-03-04 11:28:06
Message Id:  1320
Comments:
I think that the new information we have learned over the past couple of weeks helps account for a wide range of behavior and may help support the brain=behavior idea. For example, the fact that action potentials can start in the middle of a neuron, that a neuron may need input from several action potentials to continue a signal, and variations in synaptic transmission give a more complex picture of the nervous system. However, I think we also need to talk more about the effecr of the environment and the information that we receive through our senses and how that affects behavior.
Name:  Aly
Username:  adymkows@brynmawr.edu
Subject:  
Date:  2002-03-04 15:16:31
Message Id:  1323
Comments:
I am very intrigued as to how to get from the neuron to behavior. The fact that an action potential can start in the middle of a neuron is definitely helpful. If action potentials were only responses to stimuli, it would seem that we would only be slaves to the environment. However, the fact that an action potential can spontaneously occur as the result of a voltage change of some sort helps the brain=behavior argument. Are these spontaneous action potentials responsible for the thought process?

Like Kelli stated earlier, I want to know how the brain stores information. How do these neurons work together so that information is learned? What differences lie within individuals that allow a greater or lesser capacity for knowledge?? When I get a random thought, is it the result of a spontaneous action potential, or is it a pattern of neurons working together? I really want to understand how the neuron correlates with behavior. Because we can not presume that there is anything else there but cells, it must be the patterns of these cells that account for the differences in brain and behavior amongst different species and different individuals.


Name:  cass
Username:  cbarnes@brynmawr.edu
Subject:  
Date:  2002-03-04 18:13:12
Message Id:  1325
Comments:
There has to be something other than just neurons and the connections that equal behavior. How can the brain create or equal behavior when we can will ourselves to think and act? Neurons correlate our thinking. It does not mean that the neurons created the thought, or the behavior.

Think about biting into a sour lemon. Mm, not a pleasant thought, unless you actually like the pure taste. Even if you do like it, your mind creates the thought that gives one a positive or negative feeling. First we think, then we feel. It just happens that the neurons and chemicals go along with it. On the other hand, what about chemical imbalances?


Name:  Michelle Tahmoush
Username:  mtahmoush@aol.com
Subject:  wiggling?
Date:  2002-03-04 18:39:01
Message Id:  1327
Comments:
It is becoming more and more clear how the brain and spinal cord with all of the neurons can make up for the variety of human behavior. Movement can be explained pretty easily given the complexity of simply wiggling a finger. What still perplexes me is how one decides that that finger wants or should be wiggled. It could be in a response to something (an itch, a desire to call a waitress, or listening to good music,) but what if there is no direct stimuli from the environment that causes this wiggling?

We talked about how neurons can start an action potential in the middle of a neuron, which is helpful. This provides a reason for how people can simply think of something without having some sort of stimuli. A neuron in the brain (most likely in the cerebrum)can create a cascade of action potentials which will be expressed as an idea. I'm not sure how this can be done. One must draw upon a very large number of neurons in order to even remember where I put my keys this morning. Not only do I have to think about my actions from the morning, but I have to express everything in terms of a language that I can understand -- the narrator inside our heads. This makes me very curious about language.


Name:  Hilary Hochman
Username:  hlhochman@aol.com
Subject:  Neurons all the Way Down
Date:  2002-03-04 20:31:18
Message Id:  1331
Comments:
Neurons all the way down [or for that matter, changes in membrane permeability all the way across] is as dissatisfying as turtles all the way down. On what is that first turtle standing anyway? What causes the first neuron to fire -- or are we positing infinity inside each nervous system? If the answer is external stimuli, that answers one question but poses a host of others: how does the brain differentiate between signals when all are simply action potentials, and when the same neurotransmitters are used in different organ systems? Like many others in the forum this week, I am more interested in what happens when we decide to do something. As I sit and think about what to write, when does the first neuron fire? As I choose my words? As I begin to type them? What does thinking look like -- is it a physical act? And how do my thoughts cause membrane permeabilities to change and action potentials to travel, when I can not will this to happen? I wrote my last paper thinking that all the fuss about the mind-body problem was just an outdated philosophers' full employment act, but now the [relatively] simple act of trying to post this week's essay, after the class discussions about neurons and action potential, makes it seem more troubling than before.
Name:  Gavin
Username:  gimperat@haverford.edu
Subject:  Only neurons?
Date:  2002-03-04 20:32:01
Message Id:  1332
Comments:
As others have mentioned previously, it is difficult to see how we can understand behavior and memory when all we are allowed to work with are neurons. I recognize the argument that a complex system can result from a seemingly simplistic basis, but I still have trouble understanding exactly how this happens in the human brain. I suppose that there is no completely objective way to understand the totality of the neurophysiological basis for human thought, emotion, and experience, but there must be more to it than what we have covered so far. If there is truly nothing else but neurons, then what makes us so resistant to accept that they alone control human behavior? If a human has similar thoughts at different points in time, how can subtle differences in these thoughts be explained? Are we dealing with different chemicals, different pathways, or is the environment playing a role?
Name:  Mary Schlimme
Username:  Anonymous
Subject:  Role of experience in brain = behavior
Date:  2002-03-04 20:56:18
Message Id:  1340
Comments:
I think that I am becoming more convinced of the brain = behavior proposition as the semester goes on, but I think we still have some more areas to cover. Using the box model certainly makes brain = behavior an even more appealing explanation, especially since we now have ways to account for signals starting within the box and for variability in behaviors (neuronal arrangement, neurotransmitters, etc). However, I would like to discuss more about how the brain interprets and handles experiences Ė and I am becoming more convinced that just because experiences mediate behavior doesnít necessarily mean that brain = behavior is false. After all, arenít experiences what our brains perceive them to be, and canít any one experience can be different for any two people? And then canít those two people interpret those perceptions differently in their brains to perform different behaviors? I think that we need to discuss the role of experience in the brain = behavior argument more, but I think that there definitely could be a way to incorporate it into our theory without the model completely breaking down.
Name:  Claire Albert
Username:  calbert@brynmawr.edu
Subject:  Brain=behavior
Date:  2002-03-04 21:19:16
Message Id:  1342
Comments:
Although we have covered the physiological aspects of behavior, we still have to poke at so much more themes. Since the idea of behavior is a complex one, we cannot equate behavior to mechanics i.e. the activation of neuron action potentials.

We must attempt to understand what exactly is occurring within the boxes of each individual that makes his reality and reaction to the world different from his neighbor. It cannot simply be neurons, activation potentials and concentration gradients which define this so. Or is it?
What happened to experience, soul and emotions?
I think that they play a role in shaping behavior and do not necessarily result from behavior.


Name:  Shannon Lee
Username:  kitsumi12@hotmail.com
Subject:  there is more
Date:  2002-03-04 22:56:33
Message Id:  1350
Comments:
What we have discussed so far about the individual neuron and the way they communicate, I know is an integral part of our entire experience, but it is not enough to account for what the whole experiences. I think the way that the individual neuron is connected and how they make new connections is going to be very important concerning experience and memory. Also in order to get to experience, even though we have already discussed that all neurons are the same basic set up, I think there may be importanceís to experience found in neurons expressing certain characteristics dependent on where they are located and what there function is supposed to be. What makes a neuron differentiate into one having receptors for acetylcholine as opposed to GABA?
Name:  Kathryn Fong
Username:  kfong@brynmawr.edu
Subject:  neurons and behavior
Date:  2002-03-04 23:35:07
Message Id:  1355
Comments:
The mechanics of the nervous system seems to have been seriously downplayed. True, the nervous system is merely made up of neurons, neurotransmitters, etc. and based on ion gradients and action potentials, but there is much more than that. There are many crucial chemical neurotransmitters involved that bind to specific receptor proteins. There is a delicate balance of the number of neurotransmitters and other chemicals involved in the nervous system. Through experiments, which I am sure have been done, we can see that an increase or decrease in a certain neurotransmitter can have serious affects on behavior, ie Tourette's Syndrome. A chemical imbalance can have destructive affects on a person. The fact that certain chemicals of the nervous systems has such a large impact on the organism shows that to an extent that brain=behavior. The nervous system is a very complex network of neurons and chemicals and further exploration and a closer look is necessary to confirm that is the nervous system, and only the nervous system that controls behavior.
Name:  Sarah Eberhardt
Username:  idy3176@yahoo.com
Subject:  Memory
Date:  2002-03-05 00:52:43
Message Id:  1359
Comments:
Itís one thing to know that signals travel along a neuron through current flow caused by specific physical events, and quite another to accept that these signals add up to the whole consciousness of a person. Rather like we learn about atoms in grade school, and then must come to grips with the fact that only atoms make up a mountain, it takes a great deal of getting used to. It helps if one can look at some rocks: some stepping stones from the tiniest bit to the whole.

While I am not necessarily insistent that there must be more to consciousness than the sum of these neurons, I am curious as to how exactly phenomena such as memory, emotions, and thought occur. What is memory, once it is broken down to a matter of signals moving along neurons? We know that learning, when young, builds new links between neurons; is this all that memory is? Is it possible to keep building links throughout oneís entire life? If this were true, how would a person lose their memory through problems such as Alzheimerís disease or amnesia caused by head trauma? If a memory is simply a pattern of linked neurons Ė ignoring for the moment that such an explanation does not truly explain how exactly we retain an image to remember Ė then wouldnít we eventually run out of neurons to link with? Even in my own eighteen-year lifespan there are innumerable memories: tastes, smells, images, sounds. Many of these are linked with one another also; the smell of diesel conjures up the image of my fatherís truck, the sound of its engine, other scents inside the truck, the feeling of sitting in the cab of the truck at all different ages, from when I was tiny to now. It is hard to believe that all this detail, all these chains of sensation, can be contained in the space of a brain; even harder to believe that they can be expressed with the firing of a neuron. Where are memories held when they are not actively being recalled? What happens to the ones you lose? Are they are truly gone, or are the claims of some hypnotists true: that under hypnosis, you can remember more than you can normally. What is the difference between short-term and long-term memory?


Name:  Serendip Student
Subject:  spontaneity
Date:  2002-03-05 02:45:51
Message Id:  1360
Comments:
The notion of spontaneity seems to be useless if we are to relegate all control to the nervous system. Therefore, I am intrigued with the dichotomy between the nervous system's control functions and spontaneity. If a person characterizes themselves as "living in the moment and not knowing what's coming next" this is just a form of decieving oneself? Is randomness and spontaneity actually possible in the presence of inhibitory post synaptic potentials and other control mechanisms? Furthermore, is it adequate to equate, say random thought with random action potential? The existence of a random/spontaneous experience puzzles me because there are so many things present in the nervous system to disclaim its authenticity.
Name:  Priya Pujara
Username:  psp22@hotmail.com
Subject:  action vs. behavior
Date:  2002-03-05 08:40:05
Message Id:  1363
Comments:
It seems to me that one of the purposes of this class is to understand the basis of the idea that the brain equals behavior and therefore the brain is all there is. Due to our discussions about the biology of neurons I am now beginning to somewhat comprehend the biological basis for the idea that brain=behavior. That being said, Iím still stuck on the extension of the idea that the brain is everything.
Over the past few weeks weíve seen how brain=action. More specifically, our study of the neuron has led us to the conclusion that neuronal signaling leads to action of some sort. However, action in response to a stimulus does not account for all of what I consider to be behavior. Like most people in the class, I am concerned with where the decision to act derives from. A decision to act comes from an individualís brain/mind, but more complex behavior (beyond instinct and reflexes) is often influenced by onesí environment. For example, how does one account for behavior that is learned. If a human being is brought up isolated from all others, he or she will not intuitively know so many of the behaviors related to interacting with others in a particular society or culture. Such behaviors are a product of the outside environment. What I am trying to say is that action potentials themselves donít account for behavior, they merely account for action. Action in a context equals behavior, and context comes from the external environment which exists independently of our interpretation of it.
Name:  lilian
Username:  lburgler@brynmawr.edu
Subject:  I will. I am.
Date:  2002-03-05 15:53:11
Message Id:  1371
Comments:
I'm not sure how to contribute in the way of trying to answer your questions, because in many cases, I don't alltogether understand what is being asked. "Is feeling decieving?" (what the hell does that even mean?). So, instead i'll contribute just by sharing some thoughts, which hopefully are answers to the questions you may have meant to ask. I don't think that the "I-function" box is a special area in the brain that can initiate action potentials without any sort of outside stimulus. Of course, we are, just like other bodies of matter, part of our environment. But we are not merely products of our environment. Think about it: If brain=behavior means that all aspects of our environment, when they come into contact with our bodies, produce action potentials (an thus are 'translated' into chemical language) which in turn directly produce certain kinds of behavior, then choice is just an illusion. If no one really can chose how to evalute and react to their environment, then what accounts for our system of crime and punishment. A pathological killer can say that he had no control over his actions, he can even say (like Dave Berkowitz) that his actions were a result of divine inspiration, and that in that case, all men are helpless tools of god. The truth is that we DO hold people accountable for their actions, because people DO have a choice when staring down an avenue to take that road or not at all. I wouldn't say that this choice is a result of mysterious action potentials which arise without stimulus in the brain, but that in the "I-function" box, the subject (owner of the box) has the opportunity to redirect stimulus to produce an action that is thusly a result of will and not merely reflexive. Otherwise, how could people develop character or resolve to change at all? I apologize to the Catholics, (even though i was raised to be very catholic), but it seems that their interpretaion of the bible involving divine intervention, and surrendering your will to god, leaves us at a loss for what to do with ourselves, because, with that possibility affirmed, we are nothing but puppets.
"When push comes to pull comes to shove comes to step around
this self-destructive dance that never would have mattered
Till I rose
And I roared aloud,
"HERE- I WILL. I AM."" (A Perfect Circle).
Maybe, the coming of the messiah, instead, is just the realization (illustrated by the song lyrics here) that one in fact does have free will. It surely doesn't mean that one can will things that are impossible to happen, but instead that given the environment one is given (his circumstances) that he can do what he will with with those limitations.
Name:  melissa hoban
Username:  mhoban@brynmawr.edu
Subject:  proprioceptors
Date:  2002-03-05 16:57:59
Message Id:  1373
Comments:
I found our discussion on proprioceptors today in class very interesting and would like to know more about them. How is it that we can expierience something and not even realize it. I realize that this is because of a "central pattern generator" but, how is it that our brain does not allow us to really realize it like in the example that you gave inclass on feromones. Why doesn't our brain realize or experience the odor? How ddoes it choose which smells we should experience and which we should not and why is it that we have this automatic reaction? Does our brain choose which reactions are to be automatic and which we are able to concider: and if so what process causes are brain to filter the automatic reactions from the delayed?
Name:  Lauren
Username:  Lauren_welsh@hotmail.com
Subject:  
Date:  2002-03-07 16:15:29
Message Id:  1419
Comments:
In class today, we discussed how our brain can allow us to consciously perceive certain things and not others, such as feromones. The concept of perception still baffles me. It leads back to the whole concept of 'what is truth?' or 'what is reality?'. But beyond that, I couldn't help but wonder what else our brain isn't 'telling us'? How many things are we perceiving and that are affecting our everyday activities, feelings, moods, decisions....that we are unaware of?
Name:  Lauren
Username:  Lauren_welsh@hotmail.com
Subject:  oops
Date:  2002-03-07 16:17:20
Message Id:  1420
Comments:
pheromones
Name:  Kornelia Kozovska
Username:  kkozovsk@brynmawr.edu
Subject:  
Date:  2002-03-07 16:49:34
Message Id:  1423
Comments:
Following the previous comments, I am also wondering whether we can call those things which the brain doesn't tell us reality. Because relaity seems to be a concept which involves some conscious realization. And then if we are unaware, does this still mean we are experiencing that "reality"?




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