Biology 202
Neurobiology and Behavior
Spring 2001

Forum Archive - Week 4

Neurons turns out to be input/output boxes which integrate (non-linearly) current flows resulting from permeabilities and permeability changes. As such, they are both remarkably simple and remarkably sophisticated. Does understanding the properties of neurons in fact change how one thinks about behavior? Are the smallest boxes "simple" enough so that one might entertain the idea of being able to make sense of behavior without mysticism? Are they sophisticated enough so that one can imagine how even the most sophisticated aspects of behavior might in principle be imagined to result from interconnected assemblies of these boxes?


Name: ingrid solano
Username: ladybasti@aol.com
Subject: some thoughts today 2.15.01
Date: Thu Feb 15 13:36:44 EST 2001
Comments:
These were just a few thoughts I had today on the lecture.

So... additive passive current flow from all sorts of sensory neurons (possibly a thousand!) are coming into one interneuron through its dendrites and synaptic clefts... Though this interneuron uses them as additive current to decide when to fire itself, how does the brain eventually know where this impulse is coming from? How does the brain know that all these reactions are coming from the thorn in our finger, or the pebble in our shoe? If neurons only speak the language of action potentials, than what tags this information with the 'where' the multi-imput interneuron seems to know? Doesn't this all get tangled up from the sensory neuron through our narrow spinal collumn? How does the info come out to be so exact as to location?

Next, when we were hearing about inhibitory neurons, etc. I was just curious as to what level of the nervous system novicaine works, and what exactly it does.

and finally, though this is somewhat amusing, but in the spirit of 'thinking backwards', if a chicken runs around when its head is cut off because it is no longer inhibiting 'running around' then what does a human do when It has it's head cut off? Can this tell us something?


Name: in/grid
Username: ladybasti@aol.com
Subject: brain equals behavior!
Date: Thu Feb 15 13:50:35 EST 2001
Comments:
I think that it's human to believe that there is some greater part of us that is untangible and guides us as who we are. It's a concept that humanity has been looking at forever. But we haven't has science as intricate and capable 'forever'. I think there's an intrinsic fear in ignorance and not-understanding. But I think that the biases that humanity has given us, like relying on the amorphous essance that is 'who i am' need to finally be given a more fair trial. We are able to, now, build an argument from the perspective that yes, maybe the brain Is behavior. After all, there isn't something else in there, right?

The more we learn, scientists as well as those of us in this class that don't have a degree, we can see this argument forming. The fact that some neurotransmitters have been tagged as 'pleasure' or that specific instances of memory can disappear with a simple removal of cells (and yet leave other portions of memory, even more specific than just long term or short term) is absolutely Fascinating. Not only that, but it takes us in the direction that yes, maybe the brain is a place where a little of this chemical and a little of that can make up the feeling you get when you look at your mother, father or even your child. There are so many options, so many places for variation in the biology of the brain alone, that yeah... we could be mapped out up there. Maybe I'm more cynical or logic based on this very topic, simply because a layer of my neocortex has a few shorter axons than someone elses does. That's Incredible. Utterly incredible.


Name: Paul Grobstein
Username: pgrobste@brynmawr.edu
Subject: week 4
Date: Thu Feb 15 14:07:16 EST 2001
Comments:
Nice to have Ingrid's mullings to start the thoughts about this week. Yep, probably do want to think about what we've learned not only about neurons but from neurons about behavior. So, if you need something more than Ingrid to get you started, how about

Neurons turns out to be input/output boxes which integrate (non-linearly) current flows resulting from permeabilities and permeability changes. As such, they are both remarkably simple and remarkably sophisticated. Does understanding the properties of neurons in fact change how one thinks about behavior? Are the smallest boxes "simple" enough so that one might entertain the idea of being able to make sense of behavior without mysticism? Are they sophisticated enough so that one can imagine how even the most sophisticated aspects of behavior might in principle be imagined to result from interconnected assemblies of these boxes?


Name: Elizabeth Gilbert
Username: egilbert@brynmawr.edu
Subject: neuron simplicity
Date: Sat Feb 17 00:14:29 EST 2001
Comments:
Hmm...It is interesting to ask the question about neuron simplicty. It would appear that the neuron is a very complex computer. After all, it is able to carryout the thinking all the complex behaviors that we have discussed in class. But in reality, when you get down to it, the neuron is just like any other cell. It moves ions in and out and responds to environmental changes.

But I find it fascinating to know that the neuron has different neurotransmitters at the axon terminal that it is waiting to release and somehow it knows which ones to release when the signal comes down the axon. This has wide implications for behavior since releasing glutamate instead of norepinephrine can have very different consequences.

So I don't know if you can really resolve the question of whether the neuron is simple or a very advanced micro computer. On the one hand, like any other biological molecule it does what energy and ions tell it to do. It reads the DNA and produces the chemicals it needs. But it also is able to discern whether to release one neurotransmitter or the other. And differnt neurotransmitters bind to different sites which lead to the production of EPSP's or IPSP's post-synaptically.


Name: caroline ridgway
Username: cridgway@haverford.edu
Subject: weekly essay
Date: Sun Feb 18 15:06:34 EST 2001
Comments:
The principle of neuronal communication is extremely simple, however the complexity of the effects it produces is far greater than our understanding of the system. This idea has always stood as evidence, in my opinion, for why we could never create artificial intelligence that would truly rival any human counterpart. That being said, I donít think our imperfect understanding of the nervous system necessarily implies any degree of mysticism. Rather, just a level of organization that we havenít been able to recreate in, if you will, a box.

It is possible, I suppose, to concede that brain and behavior are causally linked given the immense capacity of the nervous system. However to say that nervous system activity comprises the whole of the individual is far too simplistic. There are vast individual differences both biologically and environmentally that contribute to behavior, and to consider one or the other without factoring in the influence of the interaction between the two would be inaccurate.

It was interesting to consider that the nervous system in a large part is designed to inhibit extraneous behavior as opposed to initiating desired behavior. Prof. Grobstein was correct in his assumption that, as many times as I had learned the properties of action potentials, etc., I had never stopped to consider the extent of the inhibitory role played by the nervous system. I, for one, always assumed, incorrectly, that input resulted in behavior, not in the inhibition of behavior. That makes me think of the nervous system as being a lot "smarter" in itself, rather than just as a passive vehicle for whatever was deciding what action was useful at a given time.


Name: Sarah
Username: smccawle@brynmawr.edu
Subject: Neurons
Date: Sun Feb 18 15:20:25 EST 2001
Comments:
I have to agree that neurons are both simple and complex. I think that is what makes them so successful in operating the way that they does. Yes it may only be a single cell, but as many of us have learned in the past, a single cell does many things without which we would not be here. The simple fact that a single neuron can take in signals from thousands of other neurons and utilize what it needs to operate is amazing. I think that knowing about this capability, shows us that maybe brain does equal behavior. If nuerons can do this, who is to say that this control of chemical signals is not what our behavior really is. I think that Ingrid brought up some interesting questions that I hope we will be able to formulate an answer to them by the end of the course. However, from what we have learned so far, I feel much more comfortable that brain=behavior.

I know that I still have plenty learn about brain and behavior, but I look forward to it. I think that as humans, we are curious creatures and maybe through learning about brain and behavior, we can learn why we are curious.


Name: PaShawnda
Username: pbriley@brynmawr.edu
Subject: receptors/transducers
Date: Sun Feb 18 15:33:56 EST 2001
Comments:
After descibing the stimulus- action potential relationship in class, it led right in to the implication that humans do not experience everything that reality has to offer because of the lack of receptive endings needed to interpret the sensory input. Then I began to think of things that humans do not experience, like high pitched sounds and such. I wondered what it would be like to experience these things, but then I realized that I might not be able to even wonder about having that type of experience because I wouldn't know how to interpret those imaginative sensory inputs. This makes me sad to know that we do not have a complete sensory experience due to the lack of machinery in our brain. Sad that we can't experience the highest level of some experiences, like with sweet tastes, but glad on the other hand with some other experiences that could damage us at the highest level, like infrared rays. The types and amounts of receptors and transducers in the body may be evolutionarily advantageous to our survival. But it still makes me question my own experiences. I find myself asking "Am I experiencing this as a frog would or some other animal that has different receptors/transducers?" But then there's the arguement that you can't experience other people's(or animal's) experiences, because it would be you trying to replicate that person's experience through similar sensory input in your nervous system. I guess that goes along with our interpretation of individual people's "I" function interweaving with the other boxes that make up the nervous system. I wonder if neurons in the body could mutate from chemical exposure or spontaneously to create different receptors/transducers? If so this would have to change the entire webbing network of the nervous system so that every box would understand the input being relayed. This must have happened along the way to create different species with differnt traits and level of responsiveness to the environment, right?
Name: Alexis
Username: awebb@brynmawr.edu
Subject: Mysticism
Date: Sun Feb 18 16:06:48 EST 2001
Comments:

It seems as if we have stumbled upon another double-edged sword in the brain=behavior deabte. Or, perhaps, we never pulled ourselves off of it in the first place. Are neurons both simple and complex? Can we have our cake and eat it too? Seemingly, if the answer is 'yes' we could walk away knowing that neurons can indeed provide a solution. But are they a solid solution?

To address one of these characteristics, I do agree that neurons are the simplest way of thinking about behavior: the movement of electrical impulses thoughout the body, which can be correlated to our actions and reactions. Neurons have be "precison engineered" to allow for this. Prof. Grobstein poses the question of whether or not we can escape the mysticism involved when thinking about behavior. I think part of our desire to study the brain is wrapped up in the mysticism associated with behavior. Myth and mysticism allows us to propose and conjecture in an attempt to explain what we see around us. This is the foundation of science: trying to find explanations for the things humankind puzzles over. In the end, science is part of mysticism. And if that is what leads us to a better understanding of how the brain works, then I am all for the simple/complex issue not being enough, not solving the problem.


Name: Sadie White
Username: siwhite@brynmawr.edu
Subject: some thoughts on neurons and mysticism
Date: Sun Feb 18 17:24:46 EST 2001
Comments:
This conversation about the relative complexity of neurons is fascinating. Sure, they're just cells themselves, but clearly they're quite complex in their activation and processing capabilities. It seems to me that they are definitely complex enough to explain the scope of behavior, but I don't believe that this necessarily discounts mysticism. It seems that there is, and, if we are only tying to be "less wrong," will always be, a fundamental gap between the comprehensible and the explicable. Sure, we know the basic functions of a neuron (which themselves are fairly complicated), but how much can we ever know about how and why they came to be and came to work together so elaborately? It seems that people can divide themselves into two categories, based on the way that they accept the difference between what science can observe and what it cannot explain: some believe that science will one day prevail and elucidate the current mysteries, and some believe that this proposition is not possible. It is an interesting observation of human behavior that people choose to believe what they wish to believe, regardless of the evidence, or lack thereof, that supports their positions. It seems that the two ideas (scientific reason vs. mysticism) may be fundamentally divided and mutually exclusive. Or maybe not....
Name: Sadie White
Username: siwhite@brynmawr.edu
Subject: more thoughts
Date: Sun Feb 18 17:35:25 EST 2001
Comments:
So, what if one believed that either science or mysticism were the "least wrong" way to go about observing behavior? Does the fact that both are believed indicate a fundamental flaw in the workings of the brain, or in "free will"? Specifically, why would the brain "think" that anything was correct and true, even to the point of destroying the body over which ifh holds sway (i.e. war, violence, etc.) if it were not? Is this a problem for anybody else? Is that what "free will" is? The ability to be absolutely wrong?
Name: sarah
Username:
Subject: lots of tiny boxes
Date: Sun Feb 18 19:00:18 EST 2001
Comments:
It amazes me just how many questions about how neurons work have been raised in my mind since we went through how neurons work in class. With what I know right now I would have to say neurons are incredibly complex. Like most anything they can be simplified, but I don't think that means they are simple. The different proteins in their membranes which are permeable to different stimuli, the different potentials that all work together in a certain order, the thousands of neurons that send signals through one neuron, the different neurotransmitters they release.... I could never dream to call that simple. I'm beginning to wonder it one semester is enough time to really understand one lone neuron, let alone the whole brain...

As a side-note, I found some interesting statistics in the march 2000 Scientific American. Jose Bueri of JM Ramas Mejia Hospita examined patients for 18 months and found that 39% of people who were brain-dead still had motor-movements up to 72 hours later. (the doctor determined the movements to be caused only by spinal reflexes) Just thought that was a nifty thing to remember when thinking about where the I-function's hiding...


Name: Camille
Username:
Subject: neuronal simplicity?
Date: Sun Feb 18 19:53:47 EST 2001
Comments:
I agree with Caroline in that the principle of neuronal communication is simple and that it is the result of this communication that produce sophisticated behaviors. With this said, I do not believe that we will ever be able to 'make sense of behaviors without mysticism.' The brain/behavior relationship will always be unexplainable because behavior is not only a result of internal factors but also result from numerous external (pre, peri, post natal environmental) factors that influence the organization and neuronal connection within the brain. How can we ever make sense of all behaviors without questioning how such intricate organizations came to be? I agree that there will always be questions answered with advanced technology, drugs, and treatment. However, I also believe that there will always be mysticism about the way in which these new drugs and treatment reorganize the nervous system. Yeah, we will learn more and be less wrong but we will never know it all.
Name: Claire Walker
Username: cwalker@brynmawr.edu
Subject: Neural potential.
Date: Sun Feb 18 22:49:19 EST 2001
Comments:
I think that the neuron is an appropriate system for decided how the body reacts to stimuli. I was reading an article on Neurons and it was saying how each neuron cell is very complex, although originally it was assumed to be very " simple" in earlier years. It was interesting to read that if one neural cell was isolated, scientists were able to get the action potential response, and they could see how the individual chemicals inside the cell even segregated and had separate jobs to code for a certain biological reaction. This was fascinating to me.

This paper also made connections between how the brain has been thought of as a computer. After these new complex results were examined, the scientists now said our brain was able to receive and compute digital and analog pulses (much more than any computer). Because of this complexity, the neurons have been found to be able to compute time varying stimuli and react with an appropriate response (as studied on monkeys).

I believe that the mysticism behind the brain well never disappear because we will never truly know how the brain works. Even if we had conclusive data, people wouldn't want to believe it, because it is not in peoples' nature to believe everything that science tries to prove. I don't think people want to discover the power behind the complex systems, because we like mysteries. (Mysteries are never as fun, when they are solved!)


Name: Kate Lauber
Username: klauber@haverfor.edu
Subject: Mind Games
Date: Sun Feb 18 23:05:14 EST 2001
Comments:
So I got this e-mail the other day that fascinated me. At first it seemed like one of those usual forward "do this and scroll down" sort of e-mails which I usually discard. This one, however, I didn't. It told you to answer questions and say the answer over and over to yourself as you scrolled down. The questions were 1+5, 5+1, 4+2, 2+4, 4+2 and 3+3. So, basically you were saying "6" to yourself the whole time. It then told you to repeat "6" to yourself and scroll down. Then it told you to think of a vegetable and start saying it as you scrolled down. I was doing this in a room with 10 people and we all said "carrot." According to description at the end, 98% of people say carrot after that exercise. Why is that?

It got me thinking back to our whole discussion of action potentials and synapses and inhibitions. Maybe the node of the brain that codes for "carrot" overlaps with the one that codes for "six." Would that mean that those synapses excite eachother? Is that how this whole thing works? Why is it that 98% of people say one answer to that question? It makes me think that it has to be a neural processing thing because I'd hate to thisk we were all that unoriginal. I have to think that the reason relies on some common ground, mainly our neurons.

Another thought that my friend suggested was that "six" made us think of "sticks" and then "carrot sticks." She thought it was all some sort of inherent category representation thing imbedded in all of us. I guess that brings us back to the question of behavior shaping the brain. If I have no connection between "carrot" and "sticks or six" would I still have said "carrot?" hmmm.


Name: avis brennan
Username: abrennan@haverford.edu
Subject: simple and sophisticated
Date: Sun Feb 18 23:31:55 EST 2001
Comments:
I don't think I fully appreciated the box model until I considered how the properties and principles of neuronal signaling can translate to how higher levels of the nervous system operate. It seems to me that the activity of a neuron is dictated by the principle of balance, that is chemical and electric gradients drive the action potential. Likewise, greater systems within the NS reconcile opposed forces in order to ensure smooth processing and functioning (i.e. the sympathetic and parasympathetic divisions of the ANS). To stretch the metaphor, systems of excitation and inhibition work to regulate signals and commands in much the same way that electrical and chemical gradients are responsible for neuronal firing. Recognizing this simple, fundemental principle of balance has helped me to grasp how the box model is an appropriate way to consider the NS. Not only does the box model account for the input/output capeabilities of each level of the NS, the idea of little boxes within bigger boxes conveys that the same structural, fundemntal principles are in place among all units and subunits. So in theory, the whole NS is like one of those geometric designs where the greatest unit is the same shape as the smaller compositional units (a fractal?). Maybe I should have gotten this on day one.

So how is sophisticated behavior accounted for by such simple logic? I guess I am partial to the position that operations of the NS provide a template and that the specific quality of the input carves pathes which inevitably alter the balance of the system and thus influence multiple outputs. We know now that certain inputs (i.e. stress) can change the constitution of a box or a whole set of boxes. It follows that the output (behavior) will change, and referring back to our principle of balance, so will some complimentary aspect of the system or box. I think that these adjustments and responses adequately complicate things-- the old stimulus-response model is now convaluted enough to account for some of our sophisticated behaviors.


Name: Molly Flannagan
Username: mflannag@brynmawr.edu
Subject:
Date: Sun Feb 18 23:51:59 EST 2001
Comments:
I think it is easy to see that neurons are simultaneously simple and complex: everything in nature has these seemingly conflicting properties. It seems like an amazing breakthrough to find that the nervous system is composed of tiny boxes called neurons. Human behavior is tied to tiny boxes that send signals from one box to the next... incredible. Throughout history, however, humans have celebrated the resolution of something complex into smaller, simpler parts, only to find that the parts are as complex as the whole. This is why I believe that there is more to human behavior than the firing of neurons. Something far more complex than the already complex brain is responsible for human behavior. Neurons are just the mechanics through which the mind works. Behavior can't be completely explained without a bit of mysticism.
Name: Molly Flannagan
Username: mflannag@brynmawr.edu
Subject: random question
Date: Mon Feb 19 00:04:01 EST 2001
Comments:
By the way, I am interested in forensic pathology, and Prof. Grobstein made an offhand comment in class on Feb 8th about how the K+ concentration gradient only changes when you die. Does anyone know if this can be used to determine time of death? I wasn't able to find anything about it on the internet, so if anyone has any information on it, let me know. Thanks
Name: Matt Fisher
Username: mfisher@haverford.edu
Subject: thoughts on neurons
Date: Mon Feb 19 13:03:57 EST 2001
Comments:
I started the course thinking that brain equals behavior. Through the discussion of neurons and all that they do this idea is getting reinforced in my mind. All of these little boxes are working together and they produce wondrous results that can be observed. I think that with all of these identifiable actions that neurons can also control what we don't yet understand. Sometime in the future through scientific progress it may be found that neurons control even more than previously thought. Accounts of extra senses could just be an aberration or mutation of our neurons to be like those of other organisms. Per our class discussion, humans observe a very small fraction of the world and maybe these people are just advancing and using more of their brain. Thus through all of this I am just believing more and more that neurons control behavior.
Name: Huma Rana
Username: hrana@brynmawr.edu
Subject: Neurons and behavior
Date: Mon Feb 19 14:06:31 EST 2001
Comments:
Initially, I was unwilling to admit that brain equals behavior. However, the more we delve into the functioning of the nervous system and neurons the more I am convinced (against my own will) that brain = behavior. The simplicity of the neuron is that it goes through a systematic process which can be followed, tested, and understood. The workings of the neuron are not conceptually difficult, but regardless of this simplicity, the neuron's functions are still remarkable. Through our discussions in class, I am finally starting to understand that the nervous system provides room for variety and for the myriad of behaviors that make up human kind. Interestingly, the more I learn about the neuron and its role in the nervous system, the more in awe of it I become. In a sense, I feel that despite scientific advances, the general public will always view the nervous system as a mystical force.
Name: Dena
Username: dgu@brynmawr.edu
Subject:
Date: Mon Feb 19 14:29:03 EST 2001
Comments:
The actions of neurons seem simple at first; some stimulus/input causes an electrical impulse to travel down the length of the neuron and is passed on to others until a reaction occurs. The reaction could be the contraction of muscles to throw a ball across the room after catching it. How does this happen? Several sensory organs receive signals, which travels through neurons and information is passed from one cell to another with neurotransmitter. This is where things become complicated. How does the neuron know which neurotransmitter to release when the electrical impulse reaches the end of the axon? We know the impulse is the same in all cells, it's just the movement of ions through the membrane of the neuron. Why does the same electrical impulse result in different responses?

Another aspect of neurons that make them more complicated is the role they play in our though process. It seems hard to imagine that great works of literature and theories of quantum physics are the results of electrical impulse running down our neurons. To understand how we move physically or carry out basic--or even complex life processes through neurons is not nearly as bewildering as how we manage to reason and think abstractly with them. What neurotransmitters are being released when we produce works of art and push our minds to understand relativity? And why? The actions of neurons seem simple but they must be very complex to accommodate for what we put them through. We need only direct them to muse on themselves and help us to try to understand how it is possible for them to do all that they do.


Name: Gwen Slaughter
Username: gslaught@haverford.edu
Subject: neurons
Date: Mon Feb 19 14:32:54 EST 2001
Comments:
At times it seems crazy and unreal that the millions of tiny neurons that populate my body mediate or control all of my complex human behavior. But, the actual process of the resting potential and action potential seems so simple. What makes it complicated is the different neurotransmitters that are specific to different neurons, the millions of interneurons that someone connect to your brain to tell it how to behave, and the fact that somehow it all works.

I still think it is incredibly important to learn about and understand neuron activity in order to understand human behavior. However, when learning about the smallest piece it is hard to see the big picture of how behavior actually takes place. How does my brain tell my fingers to type? How does the neuronal connection work? How do the interneurons know to keep sending the action potential to my fingers? I know that axons vary in length and it is possible that there are axons reaching from my spine to my finger tips. But, it's still hard for me to see the big picture of how it all fits together.


Name: anonymous
Username:
Subject:
Date: Mon Feb 19 17:29:01 EST 2001
Comments:
The basics of neuronal function I have no trouble with. While I'm not sure I'd call them simple, they're not too hard to understand. And in theory, I can see that complex behaviors may be the result of these simple principles; I can't think of any complex thing that isn't composed of simpler essentials. The real problem, though, is seeing exactly how these two levels are connected; we haven't yet developed an understanding of how the "simple" and relatively easily comprehensible functioning of a neuron translates into the more complex behavior. If mysticism is the default explanation for behavior, this won't be fully replaced in people's minds by neurons until the actual connection between the simple and the complex is understood.

Furthermore, even if behavior is fully controlled by the nervous system, as I believe it to be, there is still something mystical about the whole process. There are still questions beyond the scope of our scientific investigation that leave room for mysticism -- questions of purpose and origin. In other words, science and religion, if they remain suitably pliable and accepting, need not be opposed to each other, even if they historically have been.

Given the tendency of humans that I've observed (including myself) to want some measure of mysticism in the world, the realization that the two can coexist is significant. It allows the scientific explanation to be accepted without critically threatening that to which we are emotionally attached. In other words, yes, neurons can explain behavior, and yes, we can feel free to believe it.


Name: Daniel Burdick
Username: dburdick@brynmawr.edu
Subject: Re: Mind Games
Date: Mon Feb 19 17:40:29 EST 2001
Comments:
First, those anonymous comments about science and religion were me - no, I've not gone into hiding; I was just too eager to post (read, absent-minded). Anyway, I also wanted to throw in my two cents about the intriguing "six-carrot" game. It is interesting the way associations are formed and I'm sure there's some neurological basis for it. But before we get too excited, the pedant in me wants to point out that more investigation should be done. For instance, if the 98% figure is correct, it doesn't mean much without comparing it to the percentage of people who would say carrot without the prior stimulus (saying six repeatedly). Second, a host of other variables would have to be considered, including gender, age, maybe even what the subjects had for lunch. Finally, cultural effects would have to be considered.

If all those things don't change the results, then it's something interesting (and since psychology has relied on word association for a very long time, I'm sure the results are reasonably legitimate).


Name: Christine Farrenkopf
Username: cfarrenk@haverford.edu
Subject: neurons - simple or complex?
Date: Mon Feb 19 19:09:28 EST 2001
Comments:
As most of the class has already said, I think that it is interesting to look at the neuron as both a simple and highly complex entity. Although its basic functions can be easily understood (ion flow, neurotransmitters, receptors), it is more difficult to understand how these basic functions are somehow able to cause something that is complex. I have a much easier time understanding how an action potential moving across neurons can result in a muscle contraction than in other behaviors, such as thinking. When a series of neurons ends at a muscle, a neurotransmitter is released over the neuromuscular junction and causes the actin and myosin filaments of the muscle to contract. But where do neurons "go" when someone is thinking? (Another question: is a muscle contraction actually complex, or does it just seem so because it's on a large (ie, not just one cell) scale?)

I am interested to learn how nerve cells differentiate and thus result in areas of the brain, each with a distinct purpose. Is any other organ as complex in the respect of having so many differentiated cells that are specific to a certain task? I am also curious to see how the brain differentiates into the two hemispheres.


Name: Meghan
Username: mshayhor@brynmawr.edu
Subject: neurons
Date: Mon Feb 19 19:23:46 EST 2001
Comments:
I find it hard to come to terms with the idea that the seemingly simple cells called neurons can account for who we are and why we act the way we do. There has to be some aspect of mysticism in understanding behavior. If neurons can explain our behavior, does each one of us have the potential to become a great musician, writer, or athlete? Is it all a matter of what connections are made in our brain?

The fact that neurons can decide what signals it wants to process and how to go about doing so is remarkable. But how do neurons decide when to alter or stop a signal? Could it be a random process? Impulses can also arise within the nervous system itself, without regard to the external environment. Is this what makes up behavior?

In addition, I was struck by the fact that there are many more inhibitory synapses than excitatory synapses. If the chicken gets its head cut off, it runs around. What are human impulses? What behaviors do our spinal cordss inhibit?


Name: sural
Username: skshah@brynmawr.edu
Subject: video games
Date: Mon Feb 19 19:33:20 EST 2001
Comments:
So, I've been reading through the comments posted by the other students in our class, and I definitely say that I have to agree with those who feel that the neuron itself is relatively simple; its development through evolution (or what-have-you) is truly the impressive aspect of its existence--afterall, as "basic" as concentration gradients and action potentionals are, the unification of the various elements is not the type of "invention" that would happen overnight in a human perspective (though this is all relative concerning nature and chaos, the age of the universe, etc. etc.). Like many of you have said, whether or not one believes that brain=behavior directly or that there is some amount of mysticism present, there is still a significant amount of activity occurring within these cells, and the gaps between them (I know that I cannot help but picture a video game of sorts when I imagine the workings of the brain, with little neurons frantically shooting out mini ballistic missiles in the form of neurotransmitters at targets-receptors- on the other neurons, all with a sort of transient strategy to hold back and fire to maximize "points").

There is increasingly less doubt in my mind that it would be feasible for the work of the neurons to control even our most complex behavior, but I'm not sure if that is true. I admit that I want to maintain some mysticism, despite the fact that it intrinsically seems to me that brain MUST equal behavior, but I am finding it rather difficult to come up with situations that could possibly justify this stance. My initial hesitations had concerned the existence of God and the idea of infinity-- things that humans have obviously never experienced firsthand (ok, so the God example is debatable, but you get the general idea). In this sense, I wonder where the neurons fit in, as well as the I-function, and once again old Emily's views on the Brain vs. the sky. In discussion with friends, I was offered the explanation that humans had no other choice--> i.e. if they weren't controlling something, then someone else must be, and that if they couldn't see the end, then there must not be an end. These responses certainly make sense as even with these rationalizations available, humanity as a whole has certainly managed to maintain a certain level of frustration with the workings of the universe; the frustration felt by those who developped these theories and theologies must have been tremendous compared to our own. On a scientific level, it is possible that the paths used to explain regular, mundane cause-effect relationships were just applied in a slightly altered way. I'm still not sure if I am convinced by these solutions to our questions, but they are possible. I can imagine aspects of behavior forcing us to accept things we cannot experience, and I certainly don't feel that religion or God or mysticism is the answer--->there is something there, in our combinations of inhibitory and activating neurons that is capable of these concepts. Even if there is something more at work, in terms of the soul or true love, etc., I feel as if the brain is potentially complex enough to hold all of our behaviors within itself.


Name: Euree Choi
Username: echoi@brynmawr.edu
Subject: It's all so mystical...
Date: Mon Feb 19 20:39:55 EST 2001
Comments:
Whoa, who would have ever thought of such intriguing concepts. I am extremely amazed by the awe-inspiring aspects of the nervous system. It is seemingly simple, yet so complex in nature. Though, I am still fence-sitting, I am actually slowly converting to believe that brain=behavior. Yet, still, I am not so sure about the "there isn't anything else" part.

It is interesting that signals activate responses through a relay of depolarization reactions down the concentration gradient of nerve cells. The depolarization process involves amplification of a signal or a large enough stimulus to create an action potential, but what actually happens to the signals that don't become activated?

If we knew and could experience all of reality, we would be a sad people. Would we still be searching for the functions of the nervous system in order to understand that brain=behavior? Not knowing is in itself a challenge that brings excitement. I don't know if I would want to know everything there is to know about the nervous system. As Claire put it, "mysteries are never fun when they are solved." Maybe mysticism, like faith, should be accepted as valid...


Name: Kristine
Username: Kristineh44@hotmail.com
Subject: simple complexities
Date: Mon Feb 19 20:45:02 EST 2001
Comments:
I, who am always searching for ways to "have my cake and eat it too," have no problem viewing neurons as both simplistic and complex. Some of the most interesting things I have ever been interested in have been paradoxes! I think that the fundamental gap between the comprehensible and explicable (as Sadie White puts it) will always, in some sense, exist. I am even more confidents in making this assertion now that I know the limited capacity of my own perception of reality. We simply do not know all that is going on. Who's to say that there's not something else, maybe many something elses, going on in our nervous systems? That there's not some stimulus out there that we respond to without knowing it, some receptor that we underestimate. I mean, we didn't always know the name and function of the neurotransmitters and what instigated (or perhaps inhibited) their release, but they were just as much a part of early man's existence as they are our own today.

Call this puzzle mysticism, God, an amine, a perinatal hormone, or an "intentional" collision of nerve endings. In the meantime, I think that we should all strive to integrate all possiblities and be willing to blemish whatever comfortable constructs we may have established thus far. I mean, if we can have silencing thunder and tears of joy, why can't we have simple complexities or even a mystical science?


Name: Diana Applegate
Username: dapplega@brynmawr.edu
Subject:
Date: Mon Feb 19 21:04:13 EST 2001
Comments:
in thinking about what to write in last week's response, i struggled when trying to describe my thoughts on neurons. there's this conflict between their simplicity and their complexity that we've all picked up on...how can a basic unit so "simple" bring about the complexities of human existence? i almost felt guilty labelling the neuron as "simple", as i did last week. when thinking about our own behavior, we tend to glorify ourselves a little...we think/assume we're so above everything else in the universe...so therefore whatever it is that brings about our great behavior must be mystical or divine, right? it's humbling to face the neurobiological facts, so to speak, and to entertain the idea that the simplicity of the basic neuron coupled with the elegant ways in which they communicate might just be enough complexity to explain it all...but i like thinking about things this way.

the varios debates in the field of artificial intelligence, for me, have shed a lot of light on these difficult issues. for example, it's possible to create a neural net that can "learn" something simple over time. it's also quite easy to program a small robot that will successfully find its way through a maze, or to design a more complex one that will accurately deliver mail throughout a high-rise office building. the bottom line is: complex, "intelligent-like" behaviors can emerge from very basic programming and circuitry. does it really matter that the machine isn't "thinking" how we think we think inside our brains? if elementary school kids can work with a Lego Mindstorms set and build robots that perform simple, intelligent tasks, i think it's entirely possible that our inner neurological network is directly responsible for own complex behaviors.


Name: AndrEa
Username: n2tiv@aol.com
Subject:
Date: Mon Feb 19 21:27:59 EST 2001
Comments:
regarding "reality is more than what we sense" -- this is interesting, and suddenly, I am wondering what life would be like if we came equipped with other kinds of sensory receptors. For instance what if we were born with the ability to sense magnetic fields? or what if we suddenly got a new set of receptors MIDLIFE, what would that do to our brain? Actually, we have a case like that (sort of) in oliver sach's story of the blind man who got sight well into his adulthood. Seems that his brain never quite learned what to do with the new form of stimulus. He could "see" pieces and bits, but his brain just couldnt put them all together -- he didnt have the learning history that taught him to put all that stimulus from the outside world together into an intetraged whole. To me this suggests that perhaps there is something incredibly complex going on even in the transition from sensation to perception -- perhaps a whole set of neurons involved that brings the meaning (through prior learning) to the sensory stimulus.
Name: Jess
Username: jamiller@brynmawr.edu
Subject: neurobiology
Date: Mon Feb 19 21:44:30 EST 2001
Comments:
What a thought, simplicity really is the greatest sophistication. I believe that due to the simplicity of the mechanisms, it makes perfect sense that this could have occured as a result of evolution. It would have to be an easy and natural flow of events that at the end would create something complex out of many simple machines. This definitly allows us to account for variablity of behavior amoung similar animals, but also it explains why two closely related people may have similar responses to certain simuli. The best I can think is that this lends support to the nature vs. nurture idea. Perhaps some people are just programed to do things a certain way, and no matter what kind of life they may have led they will in the end make the uncommon choice. However, getting back to the questions at hand, to me this definitly explains behavior and the mind body connection without mysticism. In the end, it is simply beautiful to think that my thoughts and reactions, though unscripted, are correct because they are a real part of who I am. I don't know if that statement makes sense to anyone else, but I guess what I am trying to say is that the choices I make are a result of my neurobiology, and therefore a part of me, which makes me feel alright with the choices I make whether they be right or wrong in the end.
Name: anonymous
Username: grkdelfini@aol.com
Subject: What about G-d?
Date: Mon Feb 19 22:27:32 EST 2001
Comments:
It's pretty disheartening to be able to explain how we function all the way down to the cellular level. Ofcourse, it is fascinating and is something that biologists have come to appreciate - I am sure, but really - must we know everything? Where is the mystery? I just feel like there has to be something more. We really can't be as boring as action potentials... there has to be something else. I have just decided I will not support the idea that brain = behavior in hopes that I discover our uniqueness. Atleast for now, I would like to think of the brain as a distinct entity that does not have any connection to our soul. We have to do this or else what the heck? We will be able to simulate our biological functions and create robots that can do exactly what we do and maybe even better and then before we know it they will run the Earth. Yeah, maybe this couldn't happen. There has to be a reason this couldn't happen. How are we walking, living, breathing? Yes these actions can be explained by action potentials but something or someone must have given us "Life" This life force is something we can not explain . . .so I guess it's ok to define ourselves in terms of neurons but until we can explain the life giving force (which to me is G-d) then we are all still very unique - Wow, I just made myself feel much better. I probably made no sense at all but atleast now I can go to bed. I have realized that I tend to turn to my religious beliefs when there isn't an answer to my inquiries but I do not do this out of laziness to seek answers. I do it because I truly believe that there are answers to all of our questions but they are not meant to be known by human beings . . .
Name: Irma Iskandar
Username: iiskanda@brynmawr.edu
Subject: Neurons and all that
Date: Mon Feb 19 23:06:26 EST 2001
Comments:
I pretty much agree with the anonymous comment above me. It is frightening a little while sifting through all of the comments to read how many people are converting their opinions to "brain=behavior". I believe that yes, many aspects of our behavior are proven to be directly related to the neurons in our brain, and that the simple and yet complex structure can account for much of who we are as people. However, although we obtain more and more information about the brain, there are still many aspects which cannot be accounted for, at least for now: the makeup of personality, how an individual in a scathing childhood can grow up normally, while another individual becomes a psychopath in adulthood - these factors are difficult to prove and we cannot just dismiss them as aspects of the neurons - where would we start? Too much chemicals in the brain (if so, what?), dysfunctional permeable membranes? Like the anonymous comment, science *can't* explain everything, although we so adamantly believe it can. We almost worship science as the be-all-said-all truth because it's the only type of knowledge we can claim empirically. But that does mean that we can know everything and explain everything (i.e. all aspects of behavior) through it. I don't know, I think it will take really adamant reasoning, at this point, to convince me otherwise. So I guess I might be able to lean towards the mystic, but mystic carries many connotations, including negative, so I'm not sure that's the best word to describe my stance.
Name: Megan
Username: mmendill@brynmawr.edu
Subject:
Date: Mon Feb 19 23:23:40 EST 2001
Comments:
A lot of what I have learned about the nervous system, or biology in general, has come together to ďmake senseĒ in a way, no matter how simple or complex. The mysticism, I think, comes in part from attempting to translate our behavior (intangible) into something quantitatively measurable and tangible. I wouldnít automatically associate a neuron with behavior if I hadnít learned that it was the neuron that was responsible for behavior. It has taken incredible amounts of research to get us this far in understanding the nervous system, and as a result, a bit of the mysticism and uncertainty has been replaced with concrete testable knowledge. This seems to be the trend in science, and looks to continue as such for as long as we continue to look for answers to our previously unanswered questions.
Name: Mary
Username: mferrell@brynmawr.edu
Subject: Do neurons have a mind of their own?
Date: Mon Feb 19 23:48:28 EST 2001
Comments:
Somehow I think that these seemingly simple neurons are amazingly complex. Like Molly said, "it seems when you get down to the littlest parts-they end up being as complex as the whole". The complexity of the nervous system--I think it's quite mystical. These little boxes with their simple electrical and chemical connections seem to have an emergent property of who we are. Some of their synaptic pathways strengthened for and because of our memories, which informs or influences future neuronal firings for other reactive behaviors such as trust, love, and fear. The contents of our consciousness - all a product of passive current flow and action potentials and such? The influence of our genes, do they make our neurons and synaptic gaps have individual peculiarities? Is this who we are? Are we a machine? It can seem so mechanical but I am in awe by the creativity of it all. Is this appreciation that I experience only because I am a human with neuronal capacity for such emotion as joy? I think so but the emergent property of us machines also brings us maybe beyond that. Or maybe the magic was always with us. It seems to be with even the smallest parts. Awesome! And do the littlest parts also have a mind of their own?
Name: karen munoz
Username: kmunoz@haverford.edu
Subject: our experience
Date: Tue Feb 20 00:56:45 EST 2001
Comments:
having studied action potentials, it does seem as though the neuron is a remarkably simple item of our behavior. it makes sense with the gates that open and close in response to stimulus changes in the environment, and yet it still seems as though they are extremely complicated when one thinks of our behavior being broken down into such little "computers." and what of the fact that when we hear a sound we think is twice that of a previous sound, it is really logarithmically increased? it just seems more and more complicated when we try and rationalize things.

it fascinates me how much/little of the world we experience through our senses and how much goes on that only other animals can perceive. we think of ourselves as the most evolved of animals, and yet the rattlesnake's vision allows them to see in the dark, while we remain stumbling around in confusion. i guess it's that the rattlesnake's survival is contingent upon its ability to prey on animals in the dark, while to us, it would merely be a convenience. has our ability to develop such gadgets as the flashlight hampered our evolution into more convenient beings? i wonder how much our brains make physical evolution unecessary and how much we have to think less about things because others of our species have developed computers and such to do it for us. it just seems as though our mind's capabilities really is guiding our behavior, despite our attempts to explain things at a neurological level.


Name: rachel
Username: rkahn@brynmawr.edu
Subject: neurons
Date: Tue Feb 20 01:31:33 EST 2001
Comments:
For now, I am satisfied with explaining behavior as a result of neuronal activity. I still, however, would never claim that neurons are the one and only answer to the behavior dilemma. Maybe it is egotistical to think that there has to be something more than tissue to the explanation of why we do the things we do. I suppose, actually, that I don't even believe there is a mystical component to behavior. I just remain unconvinced that better and more thorough explanations won't keep coming and coming. I feel as though to accept a certain explanation is to ignore history and all of the theories that have been disproven which were once completely accepted as true. On a sort of frivolous side note, I wonder what people think about psychics. I surprise myself by believing in them sometimes, though my logical side refuses to actually buy into it. Anyway, if anyone does believe in psychics, I'd be interested to hear what their thoughts are on an explanation for that.
Name: Niru
Username: nkumar@brynmawr.edu
Subject: Hmmm...
Date: Tue Feb 20 01:39:10 EST 2001
Comments:
Try as I might I still am not sure of how all the complexities of the human experience can be explained by interconnected boxes...even if they pass signals along with passive current flow. I think that the great variety of paths and the sheer number of neurons does go a long way to explain the wide ranges of behavior. The idea of the 'boxes' being simple enough to be understood in terms of behavior is possible. Basically, certain pre-existing conditions allow for the possibility of synapses to be transferred from the locations of stimuli to the brain and back again.

The fact that proteins are tailored to respond to certain stimulus helps explain how feelings arise. There are different ways the proteins in the neurons of the skin allow the permeability to change, thus allowing APs to signal. For example, some neural membrane proteins change permiability due to pressure, temperature, pain, etc. This is a telling explanation for the neural mechanism. Still, this only explains one half of the nervous system. I still do not know how the neurons in the nervous system integrate these signals, gather information, and send signals back out..especially when those signals are influenced by actions and experiences of the past. How this works I still have to learn...but the possibility still clearly exists for the structure of the brain to equal behavior.


Name: caitlin costello
Username: ccostell@haverford.edu
Subject:
Date: Tue Feb 20 02:55:04 EST 2001
Comments:
I think it is definitely possible that the smallest boxes are simple enough to explain behavior. As we get smaller and smaller boxes, we seem to be coming closer to fully being able to explain behavior. It looks like it is the way of being least wrong right now is to assume that this trend extends, that the smallest box will lead to a full understanding. However, we don't really know what the smallest box is; there could be many more we are not aware of, and any of these could complicate the issue. Also there could be components that do not fall under the category of "boxes"...might they be another kind of container, "bags" perhaps? And any of these could potentially show us that our model is not working. but without evidence of them I think I'm fairly satisfied that I am least wrong by thinking that brain = behavior.

The carrot and six thing is an interesting issue. I have done this and also said carrot, but i'm pretty sure that if you just asked me to name a vegetable I would have said broccoli. We categorize information in a hierarchical model, so it makes sense to me that somehow "carrot" and "six" would fall under the same higher category, explaining their association with each other. I'm not sure how this categorizing plays into the interconected boxes idea, but it seems that there is rooms for complications to the model that we have not considered.


Name: Paula Green
Username: pgreen@haverford.edu
Subject:
Date: Tue Feb 20 03:15:48 EST 2001
Comments:
I guess when I think about neurons and its relationship to neurobiology and behavior; it is from a scientific perspective. It is difficult for me to imagine its relationship to behavior even though I know it exists. I know that the body is made up of billions of cells and the cells of the nervous system which are neurons are capable of carrying messages and communicating with each other through several processes.

So yes, the key to understanding behavior lies in the study of the properties of neurons and particularly the sites at which nerve cells communicate.

Iím sure there is a way that the smallest boxes are capable of showing both simple and sophisticated aspects of behavior. It all depends on its particular duty and how it is identified and interpreted. I guess what I am trying to say is to imagine interpretation from all perspectives. There is no way a response to a particular reaction, which could be viewed as behavior can repeat itself in the same manner or maybe it can. This is another question that comes to mind.


Name: Mel
Username: mrohall
Subject: mysticism
Date: Tue Feb 20 09:24:06 EST 2001
Comments:
What is mysticism other than a practice which reaffirms belief in a certain connection beyond the scope of the scientific method? By reaffirming such a belief, the practicioner is giving credence to the idea that simple systems are more sophisticated than current knowledge. With that being stated, is science has the same aims with simply more standardized procedure. The parts, i.e. neurons, are components of such an complex interdependent system that a omnipotent perspective of the complete understanding is obviuosly not within our abilities. Simplification of these parts is then only the narrowing of perspective and cannot possibly provide the best view.
Name: one more ? on the "dry" stuff
Username: izzy98@aol.com
Subject: like the dry stuff
Date: Tue Feb 20 09:31:26 EST 2001
Comments:
After all is said and done... I actually like the dry stuff. I say this because we looked at various types of neuronal potentials in a way different from my other biology classes. We used the same basic terms to define all types of potentials such that one potential could be used to define another. This type of definition makes it easier to build upon. Instead of having four different puzzles, we have a few basic puzzle pieces that we put together to come of with different concepts. This will make it easier for us to build the more complex ideas. The ideas that initially sparked my interest in brain and behavior.

One thing about neurophysiology that we didn't touch on, but I wrote in my notebook as a general question. Given the information we learned on Tues (2/13), how does the myelin sheath struture aid in the movement of an action potential? If some passive current flow is lost through the potentials movemnt in this structure, how then is a myelinated neuron a faster way to tranmit signals (as opposed to an unmyelinated neuron)?

I guess I will have to look that up on my own, huh? I hear others screaming against the "dry" stuff...




| Course Home Page | Forum | Brain and Behavior | Serendip Home |

Send us your comments at Serendip

© by Serendip 1994- - Last Modified: Friday, 23-Sep-2011 17:07:34 EDT