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An ongoing conversation on brain and behavior, associated with Biology 202, spring, 1999, at Bryn Mawr College. Student responses to weekly lecture/discussions. A suggested topic was provided, but students were free to write about any other observations, ideas, or questions that particularly interested them.


In what ways does an understanding of the properties of neurons and of synaptic interactions between them provide new and useful ways to think about behavior?

Name: Nicki L. Pollock
Subject: Paper Topic
Date: Fri Feb 12 13:54:35 EST 1999
After Thursday's discussion I believe I may have decided on what to focus on in my first paper. Originally I wanted to look at a neurological disease because I am very interested in health and medicine. Also, one of my cousins has a "brain disease", and I call it that because the doctors don't even really know how to diagnose him. They've seen few cases of his nature.

I am now intrigued by this idea of how one can think of behavior not as something simply being done but as something being allowed to happen. It is very interesting to consider this thought and perhaps use it as part of a discussion of neurological diseases where things seem to be "out of control" (i.e. autism). I have begun some preliminary research and intend to continue to discuss the issue further in my first paper in relation to autism (and perhaps related diseases).

I also think the "allowed to happen" possibility gives one some potentially useful new ways to think about various aspects of behavior, and am looking forward to seeing what you come up with (see below for an addendum to Nicki's thoughts). I'm curious too about the "brain disease", and would like to hear more about it sometime. PG

Name: Lauren Hellew
Subject: Behavioral Variability
Date: Sat Feb 13 15:01:26 EST 1999
I was thinking about the ways in which an understanding of the properties of neurons and synaptic interactions between them provides a useful way to think about behavior, and I was immediately struck by the way in which it may help explain the variability of behavior. I think that this did come up at the end of lecture on Thursday but we never really got the chance to discuss the idea.

At the very beginning of the semester we talked about the fact the one can never really predict animal behavior, even in a carefully controlled experimental setting. We referred to this concept as the “Harvard Law of Animal Behavior.” Looking back, I think that this idea makes more sense given an understanding of synaptic interactions. If it were the case that action potentials travel from one neuron to the next without interruption or change of any form, then one might wonder how any given input could have more than one possible output. However, given the knowledge that the continuation of an action potential depends on the sum of the input it gets from many different neurons, it makes more sense that the outcome may vary. Signal transduction is complicated by several factors. First of all, the propagation of an action potential in one neuron is usually caused by several synaptic interactions with other neurons. In addition, some of these interactions are excitatory while others are inhibitory. Perhaps such insight into the complexity of the nervous system can help to explain why any given input can have more than one possible behavioral output.

Interesting and appropriate thought, to keep exploring as we go on. Yes, "variability" is certainly easier to make sense of when one recognizes that neurons don't simply propagate from place to place in the nervous system a fixed action potential, but rather integrate a variety of smaller and more variable signals in the course of either producing or not producing an action potential themselves. And it helps still more that the smaller signals may be either excitatory or inhibitory. But "variability" is one of those words that one discovers more meaning in as one explores it (see my replies to Kim and Nicki last week). But does that account for persistance of variability even "under carefully controlled experiments circumstances"? If one really carefully controls all the inputs, shouldn't the "variability" disappear? To come back to. PG

Name: Rachel Berman
Subject: Synergy
Date: Sat Feb 13 20:41:14 EST 1999

Properties that result from communication between neurons take us one step further into understanding behavior. We can understand the phenomenon of synaptic potential but it raises more complex questions regarding the working of the nervous system as a whole. It has been established that when an action potential reaches the post synaptic neuron, a neurotransmitter (a chemical) diffuses into the synaptic cleft and binds to receptors that bring about permeability changes of the neuron. What if a particular chemical is not there and the one that is there can not “fit” into the receptors? It would make sense that a different chemicals affect the receptors of specific neuron membranes. That could mean that if a chemical is not present in a system for whatever reason, the communication between neurons is ineffective. Could we influence the system by adding or taking away certain neurotransmitters and thus altering the manifestation of various communication networks - namely behavior? Since neuron’s are not simple relays but rather integration centers that must listen to each other in order to respond, any change in their method of communication (such as changing chemicals) will have effects on how integration occurs as a whole.

Also we know that synaptic potentials are quite small and have a longer time course than the action potentials. And they are not all or nothing, but rather a variable signal. The fact that synaptic potentials take longer time could mean that coordination and integration of the signals could take much more routes and be integrated in many ways depending on the types of signals.

While examined by itself a neuron may seem like a simple element but the elements form a communication network whose complexity could account for some of the diverse signals which come out of it, the signals we refer to as behavior.

Yep, the synaptic phenomena mean, among other things, a sensitivity to the presence or absence of chemicals, more possible routes for signals, significant integration. Its not "simple", except in comparison to still more complex things. So maybe a useful conclusion (at this point) is that "behavior" (the result of the interactions of the "not so simple" things) is itself still more "not so simple". Can one specify in what ways this is so, so as to generate some catalogue of what properties one expects to emerge from interactions of neurons? PG

Name: Mary Bartek
Subject: Reality Check
Date: Sun Feb 14 12:54:50 EST 1999
From our discussions in class, I have gathered that action potentials are triggered by the opening of ion channels in the membrane of the neuron. While a single open ion channel probably will not cause an action potential, if enough Na+ channels are open, the neuron may fire, and information may be transported to the brain. Sensory neurons have different mechanisms for opening the Na+ channels. Some channels are opened when the membrane changes shape physically, due to pressure. Some channels are also opened by temperature changes, particular vibrations, certain chemicals, and some types of light. These inputs cause ion channels to open any possibly trigger an action potential. If something does not cause the ion channels to open, and an action potential is not fired, we would be completely unaware of that occurance. We are only able to percieve things that trigger responses in our nervous system. Another whole world of activity could be happening all around us of which we are completely unaware because we are unable to percieve it.

This made me start to think about the world that we know. Everything we see, touch, taste, smell, and hear is detected by our nervous system and somehow reconstructed in our brains. What we sense may not be what is really there. Also, what each person senses may be different from what other people sense. At dinner this week, my friend Joe insightfully commented that my red may not be his red. We have no way of knowing. Also, this line of thoughts helps me understand insanity. Perhaps what "normal" people consider "insane" is merely another way of percieving the world.

The other, generally unrelated, thought I had this week was about inhibitory signals. Children often wet their beds while they are sleeping. Perhaps the inhibitory signals that prevent bed-wetting are not always functioning in children.

Check. There's lots we're not "aware of" because we don't have receptors for it. On the other hand, we can transcend that limitation, by building instruments that transduce signals our nervous system can't. Which leads to an interesting question: how can we be aware enough of things we can't transduce to build instruments to detect them? And check. People may (indeed do) differ in what they transduce. So what is red? and what is insanity? We'll talk more about these. Bed-wetting? Could be. Let's see ... oh, you mean primary nocturnal enuresis" (I just discovered). Looks like (at least some) people do usefully think of this in terms of nervous system function. Might be interesting to explore further. PG

Name: Alexandra Smith
Subject: What can Neurons and Their Synaptic Potentials Tell Us About Behavior?
Date: Sun Feb 14 16:56:39 EST 1999
I think that so far, we have all seen that neurons are not as simple as they initially appeared. Although we are using them as our smallest input-output box, clearly, smaller units comprise the neurons themselves. I wrote last week that in our study of behavior it is essential to study the actions of neurons. Only by studying their interactions can we learn about the fundamentals of behavior. Having now learned more about neuron communication and synaptic potentials, I can say with confidence that these interactions can reveal a great deal about behavior.

One of my main areas of interest is in neurotransmitters. I am fascinated with the fact the presence or absence of these tiny chemicals can have dramatic effects on animal behavior, as I have learned from personal experience. Both my maternal grandmother and I unfortunately get chronic migraine headaches. About six years ago, I went to a neurologist who prescribed several medications to combat the symptoms of the headaches. After trying several different types of medications, I finally found one that worked, called Desipramine. Although it is classified as an antidepressant drug, it is also used as a preventative medication for severe headaches. I decided to do research on Desipramine to see how it works to combat migraines. Surprisingly, I found a lot of helpful information about migraines in general and common treatments. Although it is not certain, the idea is that Desipramine restores normal levels of the neurotransmitter norepinephrine by blocking its re-uptake from the synapses where it is released. I was amazed to see that this tiny neurotransmitter could have such a profound effect on my overall behavior. Certainly, without the assistance of Desipramine I would be in miserable pain and unable to function normally.

Considering this is a topic of great interest to me, I have decided to focus my first paper primarily on migraine headaches, their effect on behavior and possible treatments in preventing and combating the symptoms.

In addition, if anyone is interested, the web page from which I found my information about Desipramine describes a list of about 30 different kinds of psychiatric medications. The web address is I recommend checking it out.

Migraines are a good subject (I occasionally get them too), and I'm looking forward to your paper. Your thoughts also contribute to a more general set of thoughts that have been on my mind for a while, and to one of several themes in the forum. A couple of weeks ago Melissa expressed some concerns about "drug therapy" based, in part, on the observation that she has seen cases of it not working. Your observation is clearly one of it working. What this inclines me to think about is the extent to which different individuals (different brains) may have different responses to the same substances. Given what we know/suspect about the brain, this wouldn't be entirely surprising. It does though raise some interesting problems for clinical research and medical practice with regard to neuropharmacology. PG

Name: David Benner
Subject: neurons
Date: Sun Feb 14 20:59:09 EST 1999
I agree that neural interdependence raises serious questions for behavior. The observation that ended class especially piques my curiousity; it is interesting that there are 3x? as many inhibitory synapses as excitory ones. I am not exactly sure why this is the case since several synapse potentials need to combine to create a sufficient difference in concentration gradient to cause an action potential to arise. Nevertheless, the fact that neurons are classified regarding whether they excite or inhibit behavior suggests to me that they have an evolutionary origin, as these things tend to do, but that they are part of a larger system that exists above each cell. How, exactly does an inhibitory neuron know when to inhibit or when to excite behavior? Presumably if an inhibitory neuron is inhibited it must be by another inhibitory neuron which, itself, had to have been activated. What turns on these neurons?

I am reminded of the philosopher John Searle's "Chinese Box" argument wherein a man in a box is given Chinese characters without his knowing Chinese. Over time, the man in the box learned to associate characters with each other so that an outside observer could not tell that the man in the box did not understand what he was doing. He used his example to critique the coherence of Artificial Intelligence on the grounds that there was no intentionality in the system. Such reasoning, however, has its drawbacks. For example, language does not operate in the way Searle describes it in that he views language as a stimulus/response model as opposed to an input/output one, which is where computers differ from brains, presumably. While a given neuron may be like the man in the box, it does not follow that a properly trained neuron, or neural cluster, can, in and of itself, behave. Searle's weakness turns out to be an elucidator in the case of the brain. The man in the box is incapable of generating speech; a neuron can create an action potential, but it can't know what it's doing. Neither can we think of the whole "system" as understanding behavior or the Chinese language in Searle's example since there is nothing we can point to as a first principle, and all things must have causes.

There must, therefore, be some kind of "soul" (whatever that means, and, yes, I am being intentionally inflamitory with my diction) responsible for making decisions that result in behavior through the excitory and inhibitory neurons, or else we have a system in which all of behavior is determined by biochemistry with intentional actions nothing more than illusions. The latter may well be the case, but it seems that, given our understanding of inputs, outputs, and action potentials, these are the two main horizons for understanding behavior.

An interesting leap, from excitation/inhibition to Chinese box and "soul", but I think I'm following you. For others interested, there's some background resources and links at Exploring the Consciousness Problem. The central issues are whether "intentionality" (roughly speaking, the experience of onself having a meaning or purpose) is meaningful or an illusion and, if the former, whether it is a property of the nervous system or requires something additional. The gist of Searle's chinese room is, as I understand it, an argument that things can appear to be "intentional" without actually being so. How exactly that links to a concern over "causes" and "first principles" I'd like to hear more about. Regardless, one of the nice things about the nervous system is that it provides the missing "cause" or "first principle", at least in the sense that it provides, in addition to excitation and inhibition, what we have talked about as "spontaneous activity". Because of this, we have an answer to the question: "what turns on these neurons?" In some cases, at least, neurons are on because of internal causes: existing membrane permeabilities and concentration gradients. The latter can in turn be attributed to development, genetic information, and so forth, with the ultimate "first principle" being the random motion of particles which is always going on (together with some basic properties of those particles which influence their interactions). Is that adequately inflammatory back? Are you comfortable, at least, that we don't need anything we don't know about to account for what turns on (some) neurons? Whether that is sufficient to, in turn, provide a basis for "intentionality" is an interesting and open question, one to which we'll return. PG

Name: Patricia Kinser
Subject: illusions and neurotransmitters
Date: Sun Feb 14 23:07:43 EST 1999

I must say that I was thoroughly intrigued by our conversations last week. I especially enjoyed the comments that there is a limit to the input from the environment that the nervous system can sense. It is mind-boggling to consider the idea that there is an infinite amount of information around us that we merely don't have the capabilities to perceive! Our entire interpretation of the world around us is basically an illusion, a reality created simply by our own respective nervous systems. My illusion could be completely different from your illusion, and yet we may even have the same name for it.

Isn't it possible that this fact could account for various "diseases" of the mind, where paranoia's and hallucinations are typical? Perhaps these people, due to the "abnormal" firing and various deficiencies or overloads of neurotransmitters, develop different illusions than ours due to a more perceptive nervous system? I know the idea sounds ridiculous, but why not consider this?

To take my posting to a slightly less extravagant level, the new ideas learned in class allow us to begin to make a greater number of assertions concerning the relationship between neurons and behavior. The integration of passive current flow such that membrane potential is affected is the basis for our daily activities. Such seemingly tiny things as Na+, K+, lipid bilayers, etc... can affect our entire lives. When we consider disorders such as depression, which is thought to be associated with decreased synaptic activity involving norepinephrine and serotonin (neurotransmitters), it is encouraging to think that people who suffer from such disorders can find relief from a daily life which has been devastated by such abnormal neurotransmitter activity. This relief comes most often in the form of antidepressant drugs which affect monoamine oxidase (enzyme which inactivates norepinephrine,etc) or block re-uptake of n.t.'s at the pre-synaptic membrane. Having been involved with a person who was affected by bi-polar depression, I have seen first-hand how the drugs which treat the disorder enable patients to live more "normal" (or should I say enjoyable) lives. So, to reiterate what seems to be everyone's feeling, I think the study of neurons and their relation to behavior is useful and essential, especially when considering how many lives have been beneficially affected due to ideas such as these.

The idea of 'different illusions" in different people doesn't sound ridiculous at all, and we'll talk more about it when we get to sensory systems. It is one of the more interesting issues that arises if one accepts the brain=behavior equation: what is "illusion", what is "reality", and how does one distinguish the two? Any ideas?

Drug effects are certainly both a line of evidence for "brain=behavior" and a potential that emerges from it as a way to help people. At the same time, they are not yet a cure-all (see Melissa) a couple of weeks ago, and there are in the brain=behavior notion some reasons to suspect they will never be (for one, see my response above to Alexandra. This too is something we'll want to talk more about as we go. PG

Name: Nicole Stevenson
Date: Mon Feb 15 09:45:27 EST 1999
As a third year neuropsych student, it is quite interesting to see the more strictly bio side that does not really involve delving into the psych aspect of neurobiology, atleast not yet. Upon reading others postings I realize just how isolated I have become in Dalton. I forget that not everyone else in the class comes from the psych end of things when thinking about neurobio and behavior. The mix of backgrounds makes for interesting, differing angles on discussions.

In response to Patricia Kinser's thoughts on various "diseases" of the has in fact been talked about a great bit that the people that suffer from these problem(such as hallucinations and heightened states of arousal, anxieties) may in fact have a more perceptive nervous system. As was touched upon in class, we are all sensitive in different ways depending upon our species, chemical makeup, and various other aspects. Trephining was a prehistoric practice used in attempts to cure people gone "mad". This cure was carried out by driving stakes into their skulls to let out the evil. Mesmer thought his patients to be posessed and attempted to hypnotize the mental illness out of them. One rumor exsists that Van Gogh heard voices, so he cut off his ear. Some of the greatest thinkers and creaters were the most successful at their "craziest" times. Virginia Woolf, Mary Shelley, Hemingway, Tchaikovsky, Plath, O'Keefe, and Micheangelo all suffered from bipolar disorders.

Some people on antidepressants and psychostimulants say that while they do suffer less from some of the harsher symptoms of their illness, they also often feel muted, as if some of their spirit were taken away. This can prompt medication to be halted. Others have happier, more successful experiences. Nothing is without downfall somewhere in life, a pro is usually followed by a con. I am not trying to downplay the importance of drug therapy or the research that works towards perfecting drugs, but that there is more to "fixing" these disorders than simply popping pills and altering chemicals in the brain. I guess that's my psych talking...

Glad to have it around (pleased too that you're finding interesting things in the bio side and that you include the psych side in neurobiology). Yep, pharmacological therapeutics has limitations (see my response to Patricia above), and you've added an interesting one to the list: some people don't "feel themselves". Wonder what that means in neurobiological terms? And yes, there is some suspicion of a correlation between mental "illness" and creativity. There's a piece on Serendip on this subject (and lots of relevant stuff elsewhere on the web), if anyone is interested in pursuing it further. PG

Name: Lacey Tucker
Subject: the "personal" nature of neurons, and thoughts on inhibitory pathways
Date: Mon Feb 15 09:46:48 EST 1999
The explanation for behavior based on the inner workings of the nervous system continues to get more complex, as it should, given the breadth of human behavior we’ve identified. A general thought that has occurred to me is how unique the nervous system is within the collection of systems we have in the human body. It is the most personalized of the systems. As I struggle to verbalize this thought I find my own choice of words funny, because what we’ve been talking about all along is the existence of what we call a “personality.” We are in the midst of explaining how this collection of molecules and cells in our bodies produces this most personal of all possessions. It therefore follows that the system responsible for it would have the sort of built-in individuality we have been discovering. I think it is hard to verbalize this thought because words such as “personalized” or “individuality” connote this ephemeral sense of Self we have been discussing, when, in fact, I am using them to describe the movement of microscopic molecules over which I have no control whatsoever. These molecules though, define me. In my notes, I have written that the neurons aren’t relays, but rather integrators, and that they receive information from many other neurons and then they “decide” what to do. Here again, the word choice gets at the heart of the argument. How do these little pieces of the whole “decide” anything? It should be the Self that makes “decisions,” but we are seeing that this isn’t the case… I find the idea quite disconcerting.

The role of inhibitory neurons is completely fascinating, especially because there are so many more inhibitory than excitatory neurons. I find that this notion puts many things into place for me. As I said in class, it makes me think of the idea that we learn as children (receive environmental input) many of the things that we shouldn’t and can’t do. Much of what we are taught, what socializes us, turns out to be impulse control. We learn that we can’t do everything we want; we can’t pick our noses in public, or walk around in restaurants and eat off of all the other patron’s plates. As we learn to control our impulses, do our inhibitory neurons settle into specific pathways? Do they, in other words, “learn” which things to inhibit? This, of course, implies that our neuronal pathways are set by external information that we pick up, which I believe it does, though we haven’t yet answered that question in class. The implications of inhibitory neurons makes me think about Attention Deficit Disorder (ADD) and whether this is caused by an inability of certain inhibitory neuronal pathways to develop. Of course, the next question then, is why these pathways can’t develop in certain people, if they, presumably, are exposed to the same types of environmental input as others. It must be that environmental input isn’t the only factor in the setting of neural pathways. This implies there is a genetic component as well.

A host of interesting and relevant thoughts, any of which would be worth pursuing further and at length. Yes, we need some genetics in here, and we'll begin getting to that very shortly. Yes, we can easily imagine "individuality" in the differences in "the movement of miscroscopic particles". And inhibition can help us make sense of "impulse control" (or its absence). But, "over which we have no control"? What is "deciding"? And who does it? And where's the "Self"? We'll be trying to deal with such questions over and over again as we go along. PG

Name: Nicki L. Pollock
Subject: A slight revision...
Date: Mon Feb 15 10:22:38 EST 1999
I'm just writing to revise my earlier posting about my possible paper topic....while I am looking into autism....I meant to mention Tourettes syndrome as my major focus. Sorry for the confusion!

Back at the beginning, huh?. No problem. Sounds good. PG

Name: Carly Cenedella
Date: Mon Feb 15 14:43:44 EST 1999
One aspect of our conversation on neurons and receptors is still on my mind. I am wondering about the senses of taste and smell. They both have receptors on the tongue and in the nose that take chemical information and transduce it into action potential. In organic chemistry we did a scent lab and of the compounds that we studied there were certain structural aspects (alkene containing side chains, if anyone is interested) that caused more potent smell. The strong smell of clove for example is caused by a simple change in side chain.

When one is sick, why can't they smell or taste anything? Obviously, the structures of the world have chnaged any. There must be some change in the receptors themsleves. Perhaps the binding sites at which the sturtures of substatnces bind are now binding with something else to inhibit one's sensitivity to smell and taste.

I am also wondering what function this might serve. Perhaps by keeping the person from smelling and tasting, the body is decreasing his or her desire to eat. Perhaps by foregoing digestion, the body can use that extra energy to battle off the virus. I have been thinking about this often lately because everyone is so sick. I am not yet-- knock on wood.

Should we be sticking solely to forum enteries about our paper topic? If so, sorry. I just thought this was interesting and somewhat relevant.

More than happy to have you write here about whatever is on your mind that seems interesting/relevant. Which this certainly does. I certainly also notice lack of smell/taste when I have a cold. My guess is that this doesn't have to do with the receptors themselves but rather with something getting in the way of the receptors (mucous, inflammation?) so the relevant chemicals don't reach them as effectively. I don't know this for certain, though, and don't know if its been looked into. Regardless, it helps to make a point which we'll see again when we get to sensory systems: receptors aren't the whole story of sensory input signals; typically there are a set of relevant non-neural structures that influence those signals as well. PG

Name: Marion
Subject: Bacterial Infections of the Brain
Date: Mon Feb 15 16:00:22 EST 1999
I am interested in diseases, particularly bacterial disease. I would like to deal with a disease of the nervous system caused by bacteria, but I haven't decided what I would like to write about yet. I did a general search for "brain" the searched those results for "bacteria" and found mostly recent studies/articles on how Alzheimer's disease might be caused by bacteria. I do not want to write my paper on the topic of Alzheimer's disease as a bacterial infection, especially since this seems to be a fairly new discovery, so there would be little I could say or certain on the subject.

I know of a couple of infections, such as tetanus and botulism, and I think I might like to write about tetanus. I have done some preliminary searching and found mostly sites on vaccination and recognizing symptoms. I was wondering if I should perhaps pick another subject where there were more types of information. I also would like to know if this paper is supposed to be a kind of report on whatever we find on the net or if it is not supposed to be so book report-ish. I thought an angle I could take might be the improvements in prevention of tetanus, given the info I can find seems to relate to prevention, but that isn't very brain-oriented. It is more like a historical perspective. I would appreciate it if you would tell me if there is a minimum amount of depth into biological basis that I need to discuss if I choose to write my paper about a bacterial disease such as tetanus.

Were general comments made in class helpful? I hope so, since this may be a little late getting to you. In general (and for future reference): write about what you have found that you found interesting, and that you think others would find interesting as well. Best if after reading stuff (collecting observations) you can find patterns in it, a question which it answers or an assertion that it supports. Then its less "book reportish", and more like what scientists do/write. I don't know much about the effects of either tetanus or botulism on the nervous system; either might make an interesting paper if there's enough to explore this question. Yes, you want something which is brain/behavior related. Historical perspective is fine (often very useful) if it has that connection. PG

Name: Nicki L. Pollock
Subject: Upsidedown sight?
Date: Mon Feb 15 16:17:29 EST 1999
In physics today we were doing a lab on lenses and light and it came up that our eyes actually take in the info upside down and then it's our brain that flips it upright. Just curious as to if there are any diseases that would mess up one's brain's ability to do that, and, in consequence, is it possible for a human to "see upside down"? Just curious.

Lots on your mind this week, huh? That's good, and this is an interesting connection. We'll talk a bit more about it when we get to sensory systems. There are in fact forms of brain damage which disturb people's ability to "adjust" to variations in how images appear on the retina. Its less clear, though, whether its appropriate to say that the brain "flips it upright" (what is "up" and what "down" in the brain?). If you stand on your head, the image of whatever you're looking at is up/down flipped in your eyes so, if the brain flips things, should now look upside down. Does it?

Jason had some thoughts about your question, and I added some there. PG

Name: Joey Xiong
Username: jxiong@haverford
Subject: Just Some Thoughts
Date: Mon Feb 15 19:51:22 EST 1999
The last class was very interesting. I never thought that the a majority of neurons, which synapse on other neurons, cause an inhibitory response. I guess the question which arises is that do the neurons have a sense of an "I". It may seem so, although the actual process may be a summation of a excitory responses across the membrane. I am rather amazed at one idea though, and that is that our whole Nervous System is comprised of neurons, which synapse on other neurons. Since we are studying behavior, then everything is linked to a neuron, and that this entire notion of an "I" is also linked to a neuron.

On another note, I was doing some researching on attention deficit hyperactive disorder (ADHD). I am not sure if this is going to be my paper topic yet, but I find it to be really interesting. Since this is my first neurobiology class, a lot of thins surprised me as I started looking more into the subject. ADHD causes the infected person to feel as if they are always on the go. They seem to never stay still and can not seem to focus on anything at all. Yet, researchers have not found any real cause to the disorder. To go back to what Lacey was saying, she said that maybe the lack of inhibitory response may be a reason as to the cause of ADHD. If that is the case then, it would explain why the person may be overly active. To make an analogy to a discussion we had in class, a person with ADHD is like the chicken (who had its head disconnected). Maybe, the person with ADHD has lost some form of control over their motor neurons, causing action potentials to continously fire. I am probally completely wrong, but it is just a thought.

As we talked about in class, being "wrong" is a good thing, not a bad one (here are some more thoughts on that subject, if you're interested). Having a thought is what's needed to learn. I'm looking forward to your ADHD paper (if that's what you choose to write on). Lack of inhibition may well be useful way to think about it, though, if so, its probably lack of inhibition not on motoneurons but rather on some "higher order" box. The problem is not so much uncontrolled movement (as if motoneurons were too active) as difficulty in controlling "objectives". The notion of "higher order" boxes should probably be kept in mind with regard to the "notion of an 'I'". If the entire nervous system is neurons, it doesn't quite follow that "I" is linked to "a neuron". It might instead be linked to some assembly of neurons (and presumably is, since there isn't much in how neurons work, as we've discussed it, that looks much like an "I", is there?). PG

Name: Feyza Sancar
Subject: random thoughts/questions
Date: Mon Feb 15 20:20:34 EST 1999

From what I understand about the general function of neurons, it is possible to have a spontaneously generated action potential, which would lead to the release of some sort of transmitter substance of a chemical nature. In this case, the output is generated within the larger 'box' (the brain) by a smaller 'box' (a neuron). I guess this would explain a lot in terms of 'thinking' and dreaming in which case there really are no external inputs present to elicit action potentials. I was under the impression, however, that these particular spontaneously signaling neurons are constantly firing. I am wondering, however, if these particular neurons are generally firing and spontaneously signaling as such, or if they are generally inhibited by surrounding neurons until otherwise directed? If they are generally inhibited, I suppose this might explain certain phenomenon of dreaming. Perhaps these neurons are normally inhibited while the brain is in a conscious state and are left to their own 'devices' so to speak when the brain is in a dream state. Might this partially explain the vivid visual and auditory cues characteristic of dreams?

On a more unrelated note, I have recently been very interested in the possible effects of music on emotional states. Here I am referring purely to the act of listening to music (not the act of playing music). I am very intrigued by the implications of certain types and modes of music on the function of the brain. From what I have read on the subject thus far, certain types of music are theorized to encourage the formation of synaptic connections between individual neurons and/or groups of neurons. I wonder if it would be at all possible to actually test this theory…in an experimental fashion. From observation, it is also evident that certain types of music elicit distinct levels and states of emotional arousal. I suppose specific areas of the brain are more stimulated by certain types of music than others. Perhaps even certain neurons (those, which release dopamine, N.E. etc,) are specifically activated depending on the intrinsic nature of the music. Could it be more in the way a particular musical piece is processed that leads to the differing neuronal reposes? It must also be realized that the appreciation of music is based on individual preference…but is it possible that regardless of preference, certain types of music eventually perpetuate similar response patterns in all people? For example, it has been observed that certain pieces composed by Mozart elicit an increase in IQ, independent of the individual preference for the music. How does this work? How could these phenomena be explained by the basic building blocks of the brain (neurons) and the different potentials they produce?

Nice extension of the spontaneous activity notion to a not unreasonable hypothesis about dreaming. We'll have more to say about this subject a bit later in the course (and, of course, you're more than welcome to explore it some more on your own in the meantime). And music in relation to the brain is also an intriguing subject. I'm a little skeptical that " that certain pieces composed by Mozart elicit an increase in IQ, independent of the individual preference for the music" (can you imagine what sort of observations would have had to be done to support such a conclusion?), but the relation between music (a very complex pattern of variation in air pressure) and patterns of neuronal activity raises some very interesting questions. We're probably not going to talk much about that subject in this course, but there's a pretty good recent book on the subject, reviewed on Serendip by a previous Bio 202 student and providing a couple of useful links for further exploration. See also Jason and my reply to him below. PG

Name: adrianne lord
Subject: Still pondering
Date: Mon Feb 15 21:46:16 EST 1999
After discussing the brain's role in behavior and the implications involved when there is damage to the Central Nervous system it kind of got me interested in possibly writing a paper related to movement. In a couple of classes ago, we spoke briefly about quadraplegics and how they can not feel sensation but can still have an 'output.' In light of this, I am hoping to relate the differences in neuronal connections among quadraplegics, paraplegics and persons with physical motor deficiencies.

Its a big subject, but not a bad starting interest. I'll be curious to see what your turn up. "Sports medicine", "kinesiology", "human performance", and "sensorimotor disturbances" are all terms, in addition to the obvious ones, that might turn up something interesting on the web. And we'll be talking more in class shortly about various forms of motor disturbance and paralysis. PG

Name: Caroline Choe
Subject: paper topic
Date: Mon Feb 15 21:49:04 EST 1999
As I continue to search for a paper topic related to vision, I'm starting to find that there are many that fascinate me. However, one area that particularily caught my attention, recently, was vertigo. Some questions that I would like to find answers to in doing the paper research include: Why do these illusions of movement come about in the brain? Why do some with vertigo feel more of a sensation in the body than in the head? What exactly is this idea of "dizziness"? How can vertigo affect hearing? How conscious is a person with vertigo? I hope to be able to answer some, if not all, of these questions through extended research.

Interesting subject, and so I'm looking forward to your paper too. Vertigo is of interest, among other things, in connection with space flight. Here's a relevant NASA site. PG

Name: Deborah Silvis
Subject: neurotransmission
Date: Mon Feb 15 21:53:19 EST 1999
This question of the ways in which neural connections and synaptic transmission provide a new way to think about behavior reminds me of thoughts I expressed earlier in the semester (I absolutely cannnot believe it was a whole month ago). What I said several weeks ago was that I strongly believe that the behavior, emotions, thoughts, and memories we experience are purely the result of neurochemical phenomena. The discussion we have had in class for the past week or so has only intensified this belief for me. I think neurotransmission, and the electrochemical signaling it entails, lead to direct behavioral correlates. It seems to me that, given the intricacy and sensitivity of the neuronal activity which was the topic of last week's classes, even "behaviors" as complex as a person's emtional state can be explained in neural terms. Is that not the whole basis of psychopharmocology: that the class of human behaviors which includes feelings, thoughts, and emotions can be controlled and regulated neurochemically? At any rate, this week, just as several weeks ago (and, I anticipate, thoughout the semester) I hold to a belief that synaptic transmission and the electrochemical signalling network of the nervous system is the key to brain/behavior connection.

Can you give some examples of the "direct behavioral correlates"? And what do you do about the problem that "feelings, thoughts, and emotions can be controlled and regulated neurochemically" seems not in fact to be entirely true (cf. Nicole). As a reductionist, would you like it to be the case that they can be controlled? As a human? PG

Name: Debbie Plotnick
Subject: uninhibited views
Date: Mon Feb 15 21:57:07 EST 1999
I was quite intrigued by last week's discussion regarding the ratio of inhibitory synaptic potential Vs excitatory synaptic potentials. The example that came to my mind, I think out loud even to myself, was that of schizophrenia. It occurred to me that the hallucinations and voices that the schizophrenic individual sees and hears might be a malfunction of the inhibitory systems. We all have, as referenced above, to some degree or another what I think of as "running dialogues" in our heads and scenarios that we envision to ourselves. But the so-called healthy individual can turn these off or at least compartmentalize such on going thoughts. Can it be that for the schizophrenic person the regulatory functions, i.e. inhibitory neurons are impaired or perhaps even the excitatory neurons are more prevalent than is usual?

Conversely, the concept of inhibitory synaptic potential made me wonder about certain experiences that I have had where my perceptions have been broader than what is considered usual. Usually when I have experienced such broader, deeper, perceptions they have occurred spontaneously. But I also have had experiences where deliberate steps were taken to alter consciousness. No, I don't eat any mushrooms or cactus that can't be found on the restaurant menus. But, for example under hypnosis and also using other techniques I have been able to see and then described to another person, both during and after the experience, perceptions that I would later see exactly as I had described. Yes, I know that this sounds very strange. And I usually don't talk about such in public. But I am fascinated by the thought that I may have been thinking about such experiences "backwards." I had assumed that during altered states of consciousness, (spontaneous or intentional) that for some reason my ability to perceive things was enhanced. But perhaps what really occurred is that some of the processes that inhibit such perceptions were "turned off."j

Interesting and appropriate hypothesis for schizophrenia; an implication that might be worth pursuing is that antipsychotic drugs ought to act by enhancing inhibitory synapses. And interesting/appropriate extension to "normal" behavior. Am interested in hearing more about your experiences, and agree absolutely that "enhanced" experiences might result from some normally activity inhibitory processes being turned off. How could this possibility be further explored? PG

Name: Jason Bernstein
Date: Mon Feb 15 22:49:40 EST 1999
In her entry, Feyza was wondering about some of the same things I've wondered about. She wrote about the effect of music on emotional states. Why is it that certain combinations of notes are more appealing than others? She's definitely right that while preferences do vary, people tend to agree about what sounds good and what doesn't. Harmony sounds good. Discord sounds bad. I believe that "modern classical" music isn't very popular compared to 18th and 19th century classical music because is doesn't conform to the universal human template that dictates what sounds good. How and why did musical appreciation evolve? What reason is there for us to enjoy listening to meaningless strings of sounds? Also, what is happening on a neuronal level when a piece of music makes us happy? Some melodies can really make me feel good, like a Bach Partita, or "Come on, Eileen" by Dixie's Midnight Riders, not to mention a host of others. I just don't know enough to postulate about what is happening to produce this feeling. I guess that different types of melodies cause different types of neurons to fire. Happy music makes happy neurons fire. Or does it make regular neurons fire in a happy way, like by causing dopamine release? Of course we have to distinguish between pure melody and extra stuff when talking about emotional reactions. Most music that people listen to today is much more than melody--it includes words and percussion, which add to the effect.

Responding to Nicki Pollock's "seeing upside down" question, I remember hearing years ago that a scientist had trained himself to see upside down by wearing a pair of image-flipping glasses for a certain (long) period of time. After adjusting to the glasses, he removed them, and the world was upside-down again. So, perception can be trained--It's as adaptable as the rest of our brain functions.

See my reply to Feyza for some starting points on music and the brain. Some aspects of music currently "make sense" in terms of neurobiology, but others don't. Which is to say, probably, that, as with most things, there is some near universality to brain organization and some variation. I'm not an expert, but its my impression that "harmony", in the sense of "sounding good" has both "universal template" (probably genetic) aspects and culture-specific aspects (and probably individual-specific aspects as well).

And yes, as you say to Nicki, perception "can be trained", in at least some respects. "Prism adaptation" is commonly studied in this regard to look at underlying brain mechanisms. Here's a relatively recent press release on one such study. PG

Name: Beth Varadian
Subject: personality
Date: Mon Feb 15 23:40:56 EST 1999
I too was intrigued by the discussion that we had concerning our body and mind and how we receive inputs from the environment. I thought it was really helpful to think about inputs in terms of what our bodies and minds can detect and make sense of, and that everyone differs in the ways the inputs are processed. I am wondering if this topic of differing abilities to receive info from the environment could be related to personality. One of my initial thoughts on brain and behavior was that if there were nothing else responsible and B=B, then what about personality?... Hearing about the different, complex ways that the body and brain get info could explain (for me) certain differences in personality. I'm not quite sure yet how to define personality or describe where it comes from, but I do think that the conversation about our ability to have inputs terminate inside and inputs begin inside, helps to explain how there are so many different personalities out there when people seem to all have pretty much the same make-up.

I am still unsure if B=B, but the more we talk about the vast abilities and complexities of neurons, the more I see possibilities for the way the brain could explain behavior.

Interesting. You think at least some aspects of "personality" have to do with people do and don't pay attention to (inputs going in but not coming out?) and whether "paying attention" is or is not an important determinant of their actions (outputs without inputs)? It might be fun to look at personality theory to see to what extent this is generally regarded as a relevant parameter in distinguishing personalities. PG

Name: Kim Bibbo
Subject: Week 4: understandings of behavior
Date: Tue Feb 16 00:38:02 EST 1999
By examining the biological properties of neurons and their firings, it does lead to some insights for me regarding behavior. Many of the actions that were mentioned in class, such as wandering, uncontrolled thoughts, or new ideas, could indeed be occurring all the time without our knowledge. The physical example of the heart beating without necessary, voluntary control is a perfect example of how behaviors can happen without our awareness. With all the firings of the brain occurring without our knowledge, almost anything could happen in terms of behavior without our knowledge. After that, the major question left to ask would be the difference between voluntary and involuntary behaviors. Could our thoughts and original conscious ideas be contributed to a soul or to simple neuron firings? The reason I believe that we have thoughts or a mind is mostly intangible, but in Abnormal psychology on the 3rd of February we learned of a study by Baxter in 1992, in which people with Obsessive Compulsive Disorder (OCD) showed actual physical improvement in the brain both in drug treatments OR in psychology. The complex process of conscious thoughts can be used as a healing agent, and I believe this kind of "mind over body" is something that goes beyond neurons. But neurons, however, do help explain a wide range of unconscious behaviors like the Autonomic Nervous System (ANS).

The conscious/unconscious, voluntary/involuntary distinction is one we'll want to explore further, and will. But yes, there is increasing evidence for physical brain changes associated with both pharmacological treatments and various forms of "talk therapy". And it is certainly worth entertaining the idea that what one imagines to come from some place mysterious (a "soul"?) actually originate with some kind of spontaneous neuronal activity of which one is not "conscious". Then, perhaps, "mind over matter" actually corresponds to "conscious" influences on the "unconscious"? Might that make sense? PG

Name: Emma Kirby-Glatkowski
Subject: plans for the paper
Date: Tue Feb 16 01:32:56 EST 1999
By narrowing down behavior to units as simple as neurons it may be more possible to find cures or treatments for neural disorders. Although this idea initially made me very nervous, I am beginning to understand the implications of it. It makes it much easier to pinpoint and correct specific problems. If neurons work together in larger groups to produce behavior, maybe it would help to look at it like lights on a Christmas tree. If one (or in this case a group of) neurons is not functioning, the whole system can not work. If one could locate the specific source of the problem and in some way correct it, the system would once again be functional.

The idea of fixing problems in the nervous system is one that interests me greatly. Seeing the incredible amount of information available to us via the Internet, choosing a single topic for further investigation was very difficult. I actually became very interested in fetal research while reading a Robin Cook novel, "Mindbend". In this book doctors were using fetal nervous cells to heal neural damage such as that caused by paralysis. After some searching I came up with some amazing information on the processes involved with this sort of research. Seeing how much it has interested me, I plan to write about treatments for neural damage not only involving fetal cells, but any other methods available.

Sounds interesting. I look forward to seeing it. There is, though, one concern both about fetal tissue therapy and about your idea of locating "the specific source of the problem". Remember that neurons are the building blocks, but that behavior in general involves complex patterns of activity across lots of neurons. Problems might then have to do not with any given neuron but rather with complex patterns of interconnections among lots of them. If so, they might not be readily correctable by simply adding some neurons. Possible? PG

Name: kathy
Subject: neurons and more
Date: Tue Feb 16 02:42:31 EST 1999
I have been thinking about our last discussion. I had been under the incorrect preconceived notion that action potentials were zapped from one neuron to another across the synapse like a lightning bolt across the skies. But then the specific role of neurotransmitters becomes much more clear. And with neurotransmitters, the impulse doesn't even have to turn into an action potential. It could just fizzle and fade away. This just seemed so interesting to me.

And that is when I decided to look at the materials that I had begun collecting for my web paper. When looking at "What is Melatonin" at 2:38 in the morning everything has some light shed on it. I begin to wonder how exactly these neurotransmitters work. And especially how these work, or particularly don't work, in certain individuals. Are they just signals that fizzle before they reach their final destination? Take me and a couple of my friends for example. Is this really the effects of a neurotransmitter or is it just a placebo effect? I don't have too much faith in Melatoning and it doesn't work for me... coincidence?

The issue of why drugs might work in some people and not in others has come up several times in the forum, and you've raised an additional interesting issue in regard to it. And another interesting problem: what is a placebo effect? If brain=behavior, then it too must have something to do with action potentials and transmitters, no? There is a recent article on "The Placebo Effect" in the January, 1998 Scientific American. I'm glad you've shifted your understanding of action potentials and see why the chemical intermediate step makes a difference. Looking forward to seeing your paper. PG

Name: Jessica
Subject: Chickens
Date: Tue Feb 16 09:43:31 EST 1999
I think that looking at neurons and synapses is really helpful in looking at behvavior because of what we saw in Thursday's class - that most are inhibitory. I really like that idea. That most of the time your neurons are controlling what you don't do instead of what you do. I am still thinking about the chicken. I am a sociology major and with some help from Dr Grobstein, I have decided to write my paper on how the social environment effects the nervous system and behavior.

As I told you when we talked, I'm intrigued by the question of how to explorations of brain function with sociology, the exploration of the still more complex forms of interaction which consist of interacting brains. Looking forward to seeing what you've come up with.

Name: Caroline Murphy
Subject: what is choice?
Date: Tue Feb 16 10:08:37 EST 1999
When I think more about what the word "choice" means, I come to realize that this seemingly simple word is not very easy to define.

I would define choice as the ability to make a conscious decision among options.But when I look at what "choice" might mean in terms of the nervous system, I see that my definition perhaps needs revising. For example, when we were talking about inhibitory post synaptic potentials last Thursday, we learned that more than 75% of synapses are of inhibitory potential. I conclude from this that the majority of our "potential behaviors" are suppressed by such inhibitory potentials.

The unfortunate chicken runs around after its head has been chopped off. The best explanation for why this happens is that by severing its spinal cord near the brain, certain inhibitory synapses have been cut off from its body, and thus the normally suppressed action of running has been freed.

This idea leads me to think about behavior in an entirely different way. Using the chicken example and the knowledge that most synaptic potentials are inhibitory, I realize that behavior is not as much driven by "choice" (by my definition) but rather that behavior is what is "allowed" to occur. This is at the same time very intriguing and quite disturbing. Perhaps I would rather believe that my behavior and actions are a result of my conscious thoughts and decisions, rather than by the reactions occuring in my body to which my conscious self is oblivious to. But as always, I am ready to reevaluate and reconsider my viewpoints.

As we all should be. Yes, we'll need to talk several times about what "choice" means. But don't give up yet on your "conscious decision" feeling. Maybe one part of the nervous system can "consciously" allow or not allow another part of the nervous system to be active ("choose" to allow)? At least sometimes? PG

Name: Carly Cenedella
Username: ccenedel
Date: Tue Feb 16 16:33:27 EST 1999
I am very interested in pharmacological specificity. The fact that the neurons bind with neurotransmitter at sites other than at the synapse helps to explain the variety of behavior. There are so many types of chemicals that could be surrounding the neurons in the extra-cellular fluid that I am sure many different effects could be elicited depending on the neurotransmitter and the type of neuron being surrounded and on amounts.

I can definitely see how the circulatory system can carry chemicals, which are diffused in the extracellular fluid in the body-such as the spinal cord is surrounded by fluid. The problem I am having is that the neurons in the brain are isolated from the circulatory system by the blood-brain barrier. How would chemicals traverse the barrier into the brain?

There is even difficulty getting chemicals very similar to neurotransmitters to get into the brain. A huge problem in medicating Parkinson's patients is that the drugs similar to dopamine cannot get across the barrier. So here is this chemical that is almost identical to an actual neurotransmitter and it can't get in-how in the world are other chemicals that are not even neurotransmitters going to get into the brain?

I am starting to think about this with epilepsy. I read that there are drugs people take to control there epilepsy. The drugs are successful in a very high percentage of cases-about 80 or 90 percent. That means that the drug must cross the blood brain barrier. I went to look for how and found very little.

I suppose I am jumping ahead with questions about the blood brain barrier, but I am really curious. It seems to have such a power over what medications can help neurological disorders.

Reasonable concerns, and the course itself isn't going to help much since we're not going to talk in any detail about the "blood/brain barrier". It is however not so much a barrier in the sense of a solid wall as a set of mechanisms which make it harder for some things (though not all) to get from the blood stream to the brain. So it is quite relevant in some cases, less so in others. Let's see, where can you go to learn more about it? For the general point, any good medical physiology or medical neuroscience text. For particular cases, texts on pathology, assorted web sites. Here's one on the blood brain barrier in relation to HIV infection, and another on the blood brain barrier in relation to estrogen. So perhaps it is simply not an issue with regard to particular epilepsy treatments. PG

Name: laura gosselink
Subject: behavior originating "inside the box" and inhibitory P.S.P.
Date: Tue Feb 16 23:58:59 EST 1999

Schizophrenics experience sights and sounds the rest of us do not. Up until now I have wondered where those unusual experiences come from by asking, "what is it that schizophrenics have that the rest of us do not have ? It seems they have neural activity that originates "inside the box" of the nervous system rather than entering the box through sensory neurons. As discussed in class, there is nothing mysterious about this: self-generating action potentials commonly occur in many neurons such as those in the heart.

But I suppose I can also ask the question, "what is it that schizophrenics do not have that the rest of us have?" The behavior of chickens has led me to ask the question in this way. As discussed in class, when a chicken’s head is cut off, its body can be observed to continue running around with wings flapping for several seconds. It might be possible to understand this behavior as the result of the removal of something (presumably something originating in the decapitated head of the chicken) which inhibits running and wing-flapping behavior. In other words, maybe neurons in a chicken’s spinal chord spontaneously generate running and wing-flapping motor activity that the brain normally inhibits via inhibitory post-synaptic potentials. Thus, removing the head removes the inhibitory P.S.P. allowing running and wing flapping to happen. Are schizophrenic visions allowed to happen in the same way? Are people who experience hallucinations missing something which in most of us INHIBITS hallucinations?

Dreams seem similar to schizophrenic hallucinations in that dreams involve the experience of sights, sounds, touch, etc that do not correspond to sensory input from the external world. Like hallucinations, dreams seem to originate "inside the box." So maybe when we sleep, our dreams are allowed to happen when something inhibiting dreaming is turned off or removed.

I am starting to look at a couple of ways to investigate these questions. First, I am looking for web sites presenting sensory deprivation research. It seems that when people are deprived of sensory input, they begin to hallucinate. In other words, the absence of sensory input leads to psychosis. So perhaps there is something about sensory input that inhibits hallucinations.

Second, I am looking for sites presenting research into anti-psychotic medications which are used to control schizophrenic hallucinations. I would like to see if the research in this area supports the model of the "hallucination" as something that spontaneously occurs in everyone but is inhibited in most people.

I am also wondering whether research into dreaming behavior might be useful to this investigation.

So far the web sites I have found do not do more than state what I have restated above. For example, according to Zubek, JP, "when subjected to almost zero sensory input one suffers mental confusion which may lead to hallucinations, temporal disorientation, visions." (Sensory Deprivation: fifteen years of research. 1969.

One study indicates that neural development can be greatly altered in young animals by sensory deprivation. The research finds that sensory deprivation stifles the development and organization of areas involved in the control of voluntary movement. ( George Huntley of The Mount Sinai School of Medicine in New York) It is interesting to me that the words used here indicate that sensory deprivation stifles the development of control of voluntary activity. Am I wrong in thinking it could just as easily be that sensory deprivation allows the uninhibited flow of spontaneous activity by removing something inhibitory?

Sure. It just isn't the way most people think about it. How would one distinguish? Sounds like one (or more) interesting papers will result from your thinking/surfing. Here's a paper on a neurological syndrome in which it is believed that hallucinations are associated with sensory deprivation that you may or may not have found already. PG

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