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An ongoing conversation on brain and behavior, associated with Biology 202, spring, 2000, at Bryn Mawr College. Student responses to weekly lecture/discussions and topics.
What does thinking about Christopher Reeves (or anyone else with a broken neck) have to teach us about how the nervous system works? about behavior and the "self"? about whether brain and behavior are the same thing? Is thinking of the nervous system as an input-output "box", itself consisting of interconnected input-output boxes, useful for any or all of these questions?
The input-output box model we’ve been discussing in class is useful to a certain extent in thinking about the nervous system. Picturing the brain and spinal chord as two separate, but linked processing centers provides a logical explanation for brain-body functioning after neck injury, for example. However, I hope we don’t get too bogged down in the minutia of this oversimplified, fictitious model. I’m not sure establishing all the details of how such a model would be constructed will shed much light on the actual structure of our nervous system. Or maybe it will…
Will try not to get bogged down in "details" while, hopefully, acquiring some general ideas that help make sense of a variety of specific situations. It would indeed be interesting to know more about how Christopher Reeves (and others in similar situations) "feel". There may be more about brain/behavior one can learn. An interesting web paper topic perhaps.
PG
"else's behaviors are they?" (or something like that) is the missing end of the line? Yes, glad to have the topic of "consciousness" focused on (could be a good start for a web paper), and yes, of course, we'll talk more about it as the course goes on. There is a semantic problem here: whether we define" yours" in terms of things we observe from the outside, or in terms of what it "feels like" from the inside. And yes, its an issue that isn't restricted to cases of obvious nervous system damage. In normal life, one certainly sometimes has the sense that one has acted differently from what one intended. Was that "your" behavior? Or someone else's? If brain=behavior, how can one account for such things? What are the implications (comfortable or uncomfortable) of doing so?
PG
The situation Reeves is in, like many others suffering from spinal injuries is very interesting in terms of how the nervous system actually works. The nervous system is made up of billions of special neurons, nerve cells and nerves, which form a network of pathways that conduct information rapidly throughout the body. In Reeves’ case, at least as much as I know, there is a break or separation in the nerves. It’s a broken cable of wires, similar to our “ box”, with electrical signals making noise on one side and motors on the other side that can’t receive those control signals over the broken gap. This silence means no communication for Reeves’ body. But what we discovered in class was that even though Reeves can’t walk, it doesn’t necessarily mean that his legs can’t walk. The spinal cord has memory, it still knows how it walk, it’s just the brain can’t hear the messages the spinal cord is sending.
Is this the same Christopher Reeves from before, is he still Superman? Some years have passed after his accident and I know he has written a book titled “ Still Me”. A biography of his struggle and his fight to walk, I haven’t read it; I just read the inside sleeve. But I think the title says a lot, Reeves’ behavior might have changed but his “self” is definitely the same, meaning it hasn’t changed any it hasn’t changed (internally), rather it has grown and developed.
The model we have developed in class is a good starting point for looking at how the nervous system works. But when we look at problems that can actually happen, the simplified model doesn’t seem to tell the whole story of the nervous system and it makes it somewhat useless in answering and learning about what’s really happening when the cables sleep.
Like your notion of missing cable, and yes, its more than noise on one side and motors on the other. In fact, the problem is that the brain "can't hear the messages the spinal cord is sending" AND vice versa. I'd be interested in seeing/hearing about/having a web paper(?) on, "Still Me". Yes, of course, Christopher Reeves is still "there" and still "himself", but ... what does this actually mean? No changes at all as a result of major nervous system damage? Why so skeptical at the end? Maybe there ARE ways of finding out more about what happens "when the cables sleep".
PG
one must also take into consideration what is meant by the word "feel"? feeling is present even when the brain does not recognize it, because nerves are still responding to a localized input. perhaps we could categorize this idea differently. could we separate the feeling taking place in the brain from that in the skin?
in terms of brain and behavior being the same thing, we must remember the nervous sytem as a unit of brain and spinal cord, even when technically separated. behavior is still occuring in christopoher reeves when he moves his leg in response to a pinch, just as when he speaks. i would say this evidence points in the direction that brain/spinal cord and behavior are the same thing because even when separates they are able to function with the result of observable behavior. but, what about when there is no observable behavior and yet a person is still alive?
"Phantom pain" indeed an interesting topic since, among other things, it raises questions about where "pain" originates, in inputs to the box or in the box itself? "Where" pain is and the distinction between "feeling" and what's happening in the skin are additional interesting issues. How come we "feel" pain in the skin, if "it" is actually happening in the brain? Also interesting is what is going on with "no observable behavior"? There are so called "locked in" syndromes where the issue is quite relevant clinically. Might make an interesting starting point for a web paper.
PG
You have an argument with Melissa (among others). Let me know how it comes out? In the meanwhile, I'm not so sure I see the evidence as indicating that "the brain is the center of control". The leg, after all, does move, in an appropriate way. Maybe it does so "normally" when one is pinched, and the brain just "thinks" it did it, when in fact it was the spinal cord? And what exactly does one mean by "voluntary"? How do we distinguish "voluntary" from "involuntary"? And what might that mean in terms of our boxes? Might be a start for a web project there.
PG
But because Reeves is a different case in that the link between his brain and spinal cord were severed, this leads me to believe that those little input boxes ( ie- "sense of humor boxes") must be present. Before his injury, it would seem that the little box was linked both to the brain and spinal cord, but now that same box is linked only to the spinal cord. The connection that once was between the leg feeling box and the brain has become another box called the "I don't feel any sensation in my leg" box.
Like Hilary, I also thought about the notion of phantom limbs. Is this a case of long term memory cells acting upon years of experience or is this a result of inputs that are created within the smaller boxes that we or any science experiment cannot account for? Along these lines, this is one reason why I cannot agree with the statement that the brain and behavior are the same thing. Somewhere in that statement, our bodies and the outside world need to be incorporated. This phanton limb debate would never be a question if our bodies didn't exist. And after reading many astrology books and of course those magazines like Glamour and Cosmo, there is always an emphasis on improving the "self." The starting point in all of these improvement guides begins with your spirit, soul or my personal favorite, the mojo. And yes, to a certain extent I agree that in order to improve the self, you have to start with what pertains to your mind. However, the most important part is that the only way you can actually carry out these behavioral alterations is through physical acts. So....I guess what I'm trying to get at is that the body must be considered when discussing behavior since it is our only link to other tangible and spiritual beings.
Hmmmm. Lots of stuff in there, needing to be disentangled a bit? Let's see. We COULD presume there is something more than the nervous system (which is, of course, part of the body); in which case it would make sense to for Glamour/Cosmo/etc to encourage "improving self" by starting with .... "mojo". But what if "brain=behavior"? Is there a way to rephrase the Glamour/Cosmo advice in terms of nervous system boxes/inputs/outputs? Heartbeat an interesting case. Wonder how much we CAN control heartbeat? And how? Might be an interesting web topic in there.
PG
The use of the interconnected boxes is helpful in thinking about the nervous system. When the two major boxes are no longer connected, each continues to perform its task as before, although signals can no longer be sent between the boxes. I have been thinking about ways that connections between the brain and spinal cord could be made. If someone breaks a bone, the bone usually grows back together. Also, in certain instances of brain damage, especially in younger people, the brain is able to make new connections to perform the same task. That is, a connection that controls a certain action may be severed, however, the brain creates new pathways so that the same action can be accomplished by a different route. With the growth of bone and the brain's ability to work around damage, why can't connections regenerate between the spinal cord and the brain? If the brain and spinal cord cannot "grow" back together, and if the messages from the spinal cord to the brain are relayed via electric pulses, why can't a conductor of electricity be used to enable the communication?
Good questions. As we'll see, the nervous system uses signals which are detectable as electrical events, but the signals themselves are not "electrical" and so couldn't be transmitted along a conductor such as a cooper wire. As for why the nervous system doesn't regenerate (like bone), that's a harder question, one under active investigation, and might make a good web paper. And, on Christopher Reeves, Melissa disagrees with you about where he is, and I'm not sure we can conclude that he isn't ALSO in the spinal cord, since we don't have a way to ask.
PG
And on exactly what the impulses are, and how they are transmitted/interpreted, which we're getting to in class. Can the brain/spinal cord "realize" things? What does the nervous system do with "illogical" signals? Interesting questions. Can you imagine a way to explore them with some new observations? Any situation in normal behavior when the signals are "illogical"? What happens?
PG
As to the question of whether the nerves could just find a way of rerouting themselves. That seems rather interesting. I think of people that have severed a finger or something. I have heard that people that when reattached, after some time, they are able to feel sensations upon that finger again, true not as before, but still something. Does this give hope to Mr. Reeves? I don't know, because I am comparing two things of totally different degrees. One is a body another is a finger.
Yes, there is a big difference of scale (numbers of neurons and targets involved). But the finger case may well be instructive, if one could find out more about it (and/or similar situations). "they are able to feel sensations ... true not as before, but still something". How similar/different is it to "before"? Why? Might make an interesting web paper, if one could find enough about it.
PG
I believe this provides evidence that the “self” resides in the brain, and that the “self” or brain is not equivalent to behavior. The movement of Christopher Reeve’s leg when pinched is a behavior, because it is an observable action (a response to external stimuli). The leg does not have a “mind of its own”, meaning it cannot interpret sensory input. Only the brain can interpret sensory input as a “feeling.” This seems to me to be evidence that the brain and behavior are not inextricably linked. While the movement of Christopher Reeve’s leg is the result of the nervous system (the spinal cord and PNS, in this case), the movement is divorced from the brain. This also indicates to me that the difference between “the brain and behavior are the same thing” and “the nervous system and behavior are the same thing” is more than just semantics. At this point, I might agree with the latter but not the former.
I do believe that it is useful to think of the nervous system as an input-output “box” which is made up of interconnected input-output boxes, which in turn consist of input-output boxes. The example we discussed seems to imply that the brain and spinal cord are two difference boxes that, when functioning normally, communicate with each other. I am frustrated that we as a class aren’t doing a better job of defining our terms before we try to tackle these tough questions. What counts as a behavior? What evidence do we accept that Christopher Reeve “feels” his leg being pinched? Also, I think that understanding the basics of nervous system structure and function would give us a foundation on which to answer these questions.
And maybe even to sharpen our "definitions". It often happens that we don't actually know how to define things "properly" until we have some observations that require us to recognize that our normally used words actually no longer quite fit. Another way to say the same thing is that science is largely a matter of "deconstructing" words, and making new definitions. What's at issue here is what does one mean by "feeling" and by "self" and by (as you say) "behavior". Somehow, we need to redefine these terms (or create new ones) so as to describe the reality that Christopher Reeves' foot moves as if it was hurt but he doesn't report "feeling" pain and denies that he "himself" moved it. So, maybe there is more going on in the nervous system than is obvious from behavior observed from the outside in "normal" people, and so we need a new definition of "behavior" too?
PG
However, I still cannot agree with the statement that "there's nothing else but brain". There are some phenomena that cannot be explain with our box model of the nervous system. For example, some healthy people experience "kanashibari" - a Japanese term for a state of "being tied up" temporarily. A person in kanashibari (usually happens when one is lying down awake) cannot move his body no matter how much he tries as if something invisible is binding him to the bed or floor. In this case, one's body does not respond to the signal sent by his brain. Something is oppressing his brain's function to produce a behavior. I know that at least in Japan, kanashibari is considered to be done by evil spirits taking over one's body. The contrary phenomenon is also possible - that a person's body moves against his will. How can we explain these phenomena in terms of nervous system?
Would like to hear more about your uncle, since it suggests that there are some other boxes that can become disconnected. Would like even more to hear more about "kanashibari". There is, in western medicine, a syndrome called "sleep paralysis", and another called cataplexy and/or catalepsy, which may be related. Well worth looking more into, writing about, as a web paper?
PG
I do agree with the statements that the brain houses self for another reason, becuase that is where all the experiences, observations, mistakes and memories are collected. These really have to do witht he heart of "who" someone is and what personality they have. Which would mean that Christopher Reeves still has his "self" all the memories and experiences are still there and no trial and error that has made him the personality he is has been taken away from him which means he is still in control of that aspect of his corporal being. He can control his personality functions, he can control brain functions therefore one is within the other.
Actually, "he can control brain functions" sounds to me more like one is "outside" the other, no? And what about Christopher's poor spinal cord? Why are we so willing to deny it "selfness"? After all, it can't talk so maybe ...? Is interesting to think in the abstract about whose hand a transplanted hand is, but is even more interesting to think about what kinds of observations one could make to try and answer the question (and hence maybe come to useful redefinitions of some of the terms; see my response to Stephanie above.
PG
It does indeed raise interesting questions and clinically relevant questions about how one decides whether a "self" is there or not. Worth looking into, perhaps, as a web topic? How do people currently evaluate whether a patient is "alive"? Is it appropriate or might it need to change? In Reeves' case, though, remember that there isn't a total "loss of behavior". He still speaks, smiles, etc since there are motoneurons for muscles of the head above the transection.
PG
I also found Maria's comments interesting (that the spinal cord still knows "how" to walk even if the brain is unable to receive and process that signal). Of course, it makes sense that the someone with a broken neck still could do everything as before if only there were some means of getting the message from the brain to the spinal cord. So the ability to walk, etc. is still there.
And, finally I was interested in what Andrew said about the brain being able to accomplish the same desired output by a different means if it becomes damaged. I had never thought about that before and hope to learn more about that phenomenon.
Yeah, but maybe not QUITE the sam person, and maybe with the same ambiguities as in a normal person about what behaviors actually do or do not belong to the person? (see some of my earlier comments). Walking makes sense once one accepts that the spinal cord has substantial abilities (ie is not just following instructions from the brain). Yes, very interesting that the brain can do something a different way if one way compromised. Will talk a lot about that as we go along. How do you suppose it "knows" it has to find another way? And does it have to create them each time to fit the particular case?
PG
Thinking and feeling, because they are located in the brain, are incapable of influencing or being influenced by the portions of the body below the severed connection. Professor Grobstein concluded from this that since thinking and feeling are located in the brain then the “self” too must be located in the brain. When he first mentioned that the self could be located in the mind my immediate reaction was “so the brain is no longer a physical object- it becomes an entity all his own; it is warped to fit the model.” He seemed to be incorporating non-tangible items like the self into a very tangible brain and in doing so no longer restricted the brain to a physical object. The problem I saw with that was the brain is a physical object!! By the end of the discussion, I was finding myself thinking that the self was located in the brain region. Most of Christopher Reeve’s nervous system is no longer communicating, yet he still has his personality and his self. The fact that his brain seems to be the only part of his body functioning according to his personal will seems to indicate that his self is indeed located within his brain. In rethinking this, I am willing to admit that Christopher Reeves did not lose his self when he broke his neck, but I still not willing to admit that the self can be confined to a physical object. There is something about that statement that just does not sit right.
Overall I loved this discussion. The only other on the spot reaction that I marked down concerned the model that we are creating. Someone in class mentioned the idea of a central processor and in response to this remark we added the boxes. To myself I posed the question, what about inputs that may cancel each other out? I thought perhaps there should be some sort of internal calculator, which determined if all the inputs were positive enough to create output or negative enough to delay output. Just a thought!
Nice thought. And an interesting set of questions which we'll get to shortly. Is there a "central processor"? Or just a lot of boxes (a lot of processors?)? And maybe some kinds of "cancelling" process? We'll see. In the meanwhile, am very pleased that the "discussion" works for you (as it does for me; I usually come away from class thinking something different from what I went in with). Intrigued as well by your backing and forthing on the "self" in brain notion; is indeed an interesting question whether an "intangible" can be made tangible. Keep me/us posted on your thoughts on this matter as we go along.
PG
Yet if so, is the box for the "self" inside the box for the brain? I find this hard to do because I want to think that there is something special about the "self" and that it is a special box
I guess I see that our system is a inter-connected network and although a "normal" person has almost all or all the parts working (and connected), these parts are relatively independent of each other.
Thinking about the example of christopher reeves also made me think of the opposite example. If a person had a part of his body amputated. Does the brain still think its there? or doesn't it? I remember when I broke my arm and some nerves were damaged, I couldn't move my fingers even if my mind tried to move them. so I wonder hmm....
Very nice extending thought .... indeed if self is in brain (maybe indeed a box within that box) then perhaps it can have body parts even if the actual parts are missing? Will talk about such things, in connection with phantom lims phenomena, a little later in the course. Would, in meanwhile, love to hear more about your experiences with your broken arm ... does indeed sound like Reeves' sort of case. And ... were nerves damaged enough so you could not only not move your fingers but didn't feel them? If so, were they nonetheless there? yours?
PG
That's the story, alright. Yes, a lot like tin can telephones. But, don't underestimate the spinal cord. Its not just "reflexes" (as I said in class, we'll try and get rid of this term), but pretty sophisticated capabilities which simply lack hearing/seeing/speaking/etc because those involve rostral inputs and outputs.
PG
I don't necessarily see why we need to put everything in neat little boxes, except to establish elementary understanding of concepts. The self is no exception. When we limit something like the self to a bundle of neurons and sit and argue over which bundle of neurons it is, we might(I'm not saying we are, but we might) lose sight of the expanse of infinite space, the infinite capacity it might encompass.
An interesting question that arises if the brain is the self is, do we account for the growth in our selves to the growth in our brains? I remember that some animal studies indicate a growth in brain structures can accompany learning, but does this mean that the brain grows in response to learning (growth of self)or vice versa? Neither? I guess they could be correlated without one causing the other? But ignoring that thought for a second, does all learning come with a growth/ change in brain structures? Does this mean that our selves are most expansive in our early development, and degenerate as we age? (Aren't neurons supposed to die out even though they aren't regenerated?) How does the brain accomodate big revelations, insights, or losses? (I'd like to see a PET scan of Buddha's brain before and after Enlightenment:) )
Nice indeed to have the connection to any earlier course (what was it? how taught it?), hope you'll get comparing thoughts between the two as the course goes on. If we locate "self" to a "physical box" does that mean it is "finite"? Not necessarily actually. How much math do you know? Enough to know how many real numbers exist between 1 and 2 on the number line? Infinite possibilites can in fact be present in a "finite" (ie bounded) space. Perhaps so too can regret, responsibility, accountability? We'll try and look more at these as we go along. The brain does indeed change as one learns and "grows", so that's not too much of a problem (though the issue of "self" and how it can both change and stay the same isn't quite so clear). For that question, as well as in connection with what the brain might or might not be doing in relation to enlightenment you might be interested in a paper written by an NBS student several years ago: Buddhist Meditation and Personal Construct Psychology. It is more about the psychology than about the physiology of meditation, so there's plenty of room for an interesting web paper on the latter subject, if you felt inclined. There's an interesting new book on the subject: Zen and the Brain (MIT Press) by an American neurologist who spent some time in Zen training in Japan. j
PG
Christopher Reeves is still the same "self" even though the accident has placed a heavy amount of restrictions in his physical behavior. Since our last class, I've been thinking about something that few of you have already mentioned. If we state that the brain is everything and there is nothing else, how should we treat those who have been pronounced to be "brain dead"?
The issue of what is meant by "brain dead" (and how such people should be treated) is indeed an important one (and might make a good starting point for an interesting web paper). I agree we need to know more about how the different boxes normally talk to one another, but am a little puzzled by "can't account for his paralysis". Why not? Seems to me we know that it isn't REALLY paralysis (eg, the leg can withdraw when pinched), is only an inability to move on instruction (since auditory input arrives above the transection) or by will (since "self" is in brain?). What remains to "give reasons for"?
PG
As for phantom limbs, I too am interested in the subject, mostly because I am fascinated by the idea of regeneration and the amazing homeostatic and regulatory abilities of the nervous system and it’s receptors. It seems to me that this story is more complex than amputees who “just feel pain” once in a while in a leg that doesn’t exist anymore. Indeed those properties are being put to use in order to restore the function of limbs. For example, I found the following recent article in Scientific American. I am not suggesting that this article or others like it would seve to fully explain the phenomenon(especially because this is not an amputee cas). However, I think it worthwhile to see the way in which the scientific community attempts to explain the phenomenon. The following is a summary of the article for those of you who do not have time to look at the link. However, there are soem good links within the article to basic definitions and vocabulary used to describe the phenomenon.
"Summary: Born without a left hand and lower forearm, Melissa makes the signal oscillate by moving either a tendon or muscle in the arm taht would have been used to flex her thumb. The electric signals represented by the fluctuating lines can be used to move independent fingers in what may be the first dexeterous prosthesis. Melissa, like some toher subjects, reports that she can feel control over missing hands and fingers-a phenomenon known as phantom limbs."
Interesting article indeed. Thanks for telling me/us about it (the first link in the forum (by someone other than me); glad you're becoming a cyberspacer). Along these lines, I recall a paper and news reports several months ago about rats "bar pressing" based on brain recordings rather than physical movement. Might be worth tracking that down (and, with what you found) might make an interesting web paper. I don't (as you know) like the "reflexive"/non-reflexive distinction, but we'll talk at some length about the "instinctual"/non-"instinctual" one. Yes, all behavior is done "by oneself", but that's not quite the same as saying all behaviors involve "self". There is a real distinction between "voluntary" and "involuntary" that we'll have to look more into (its a less straightforward distinction than the traditional terms suggest). And it doesn't break cleanly along "instinctual"/"non-instinctual" lines (as we'll see)
PG
Secondly, I was intrigued by Prof. Grobstein's question, "Can Christopher Reeves FEEL you pinch his leg?" This seems to me much like the question about the tree falling in the forest. When a tree falls, it moves the air and creates sound waves. But there is no receptor around to gather the wave and turn it into information to be processed. Without an ear and a brain or a microphone and a radio to collect this information, it seems to me that there is no "sound" even though the sound waves are being produced. But we all know that this is debatable. In the case of the pinch, we have more than we do in the sound case, sice the touch receptors and pain receptors are still functioning and sending on the information. But he has no sensation of it since his brain never receive sthe information to process. Thus he himself cannot "feel" it, even though his skin and the receptors "feel" it.
My last thought has to do with someone's question about the spinal cord being able to be "reconnected." I was watching the television the other day and saw a story about how the head of a chimpanzee was successfully transplanted onto the body of another. Much like Christopher Reeves, this monkey was paralyzed from the neck down, since tehy are unab;le as yet to connect severed spinal cords. But, as suggested in Revees' Super Bowl commercial and mentioned by the doctors, technology is in the works to do just that. In fact, the doctors feel that in the future, head (and thus brain) transplants of people suffering severe disease or injury to their bodies will be able to be done using bodies of those who are brain dead. Personally, I see this as a scary possibility, but such a procedure would allow us to better see where teh self is. If it is all in the head, the person shouldn't change. But if it lies somewhere else, maybe he/she will. I suppose only time will tell...
As I said in class, I'm not sure time WILL tell on this one, but it is indeed a relevant thought experiment (at least) that we should keep in mind as we learn more about how the brain and the rest of the body intersect. I like very much your connection of Reeves' "feeling" to the tree falling in the forest problem. We'll talk about the tree a bit later in the course, and come to pretty much the conclusion you do: there are certainly disturbances in the air but no "sound" in the absence of a receiver/translator/"meaning-maker" for those air disturbances. The Reeves' case, though, is a little more complicated, because we don't in fact know whether there is or is not a "meaning-maker" in the spinal cord.
PG
Actually, it would appear that "behavior" may NOT be determined by the "self" alone, if we take the Reeves' observations seriously. The leg moves when it is pinched, but Reeves' asserts that he didn't move it (and can't, in fact, move it). So something else is contributing to behavior (ie, moving the leg), no?
PG
An interesting and sophisticated analysis; interesting to see whether others in the class buy it. Among other things, it suggests that there may well be circumstances in which we ought not to "hold people responsible" (legally, morally) for their behavior, even if it is clear to one and all that their bodies were involved? Might be a set of issues worthy of some exploration for a web paper. As for the vat experiment, we'll talk more about that. But, even if it came out as you describe, there's a problem. What about the spinal cord? Is it possible that, undetected by us, there is a Christopher Reeves' THERE, as well as in the brain?
PG
It started by saying what would happen if the spinal cord were severed. For brevity's sake, the cat cannot move voluntarily - below the head, it is basically a bundle of reflexes (I know that I'm not supposed to use that word, but we all know what I mean).
It then moved up the different divisions, going forward and separating each area from the ones in front. First you get a comatose vegetable of a cat, then one that can move without any coordination or balance, a blindly rageful cat and so on. It is that it is not a truly recognizable cat (in terms of behavior) until you lesion the absolute newest tissue (evolutionarily speaking of course).
My point is this: with all these boxes that are interconnected,at which point of breaking these connections does "Christopher Reeve" or "Richard Cruz" cease to exist. When I have a brain injury that takes away any balance, turns me into a blind raging fury, or when all that I can do is breathe, digest, and keep my heart beating?
There's actually a reason not to use "reflex", which has in part to do with biopsychology textbooks and the way they present the relationship of "boxes" to one another. What DOES "a bundle of reflexes" mean? If "stereotyped input/output relationships" is the meaning, it is simply not true (the Harvard Law of Animal Behavior holds, though less so, for the isolated spinal cord). If "inputs go in to the same part of the nervous system that outputs come from" is what it means, then that is equally true, for some behaviors, of the brain. If "simple interconnections between inputs and outputs: is what it means, it is again simply not true (even, as we'll see, for the classic tendon jerk). If it means "involuntary", as opposed to "voluntary", then it is papering over some very difficult problems that really need to be explored more explicitly (as we will in discussions to come). How does one distinguish "voluntary" from "involuntary" movment in a cat? The additional problem is that the textbook implies that the results of higher and higher section can be understood in terms of successive addition of functions to those observed with lower sections. This is simply not true. There is MUCH more "ability" in the spinal cord than is apparent in the "comatose vegetable"; damage to "higher" (actually more rostral) structures doesn't uncover what more caudal structures are capable of doing on their own but rather shows what they do in the presence of a damaged rostral structure (which frequently is less than they are capable of doing on their own). To talk much more about ... and hope you'll continue to be the biopsych interlocutor, since it helps to keep me honest (and, perhaps, helps others to see why we go in some of the directions we go).
PG
where is self? i leave that to how each indiviudal defines his/her -selves. in the movie, "What Dreams May Come," robin williams defined himself as his brain, only to be proved wrong by cuba gooding jr. to robin williams, there was no brain without the body and there was no self without the brain. i, on the other hand, feel many of my emotions - that are dthen reside in my body without my brain? i don't think so.
my behavior is expressed through my actions and is often times spurred by my emotions. we know actions are output caused by a series of chemical reactions within. emotions are part of that same chemical process that so often, if not always, begins in the brain. again, i move into - "people are only chemical reactions" mode.
i define my self as that marriage between the spine and the head. when that marriage is broken, as is the case with christopher reeves, i think that people move self into the head because that is the region they are actively aware of and that recieves the input and expresses the output most common to our species; speech. i would probably go mad as i cannot imagine defining who i am without the physical sensations my body experiences. a person defining himself by his intellect or religion might be better of, while an athlete or an artist who defines himself by the physical product of his output might share my sentiments.
in today's class discussion, i was constantly reminded of orpheus, that greek character who's head was almost immortal though his body died early. orpheus was orpheus without his body. but then again, how many movies do we see wherein some character loses his head while the body gropes like a separate cognizant looking for the head so as to be fully rid of it a( by destroying it )? if any one reads batman, mr. freeze's body deteriorated while his head lived on. with these examples in mind, i think our culture forces us into a prejudice against the body being or having a self. perhaps with good reason - i cannot get out of that mindframe.
Which mindframe? Seems to me there are two here. One is self/emotion/chemical reactions. The other is self/brain/head/body linkages. Interesting to think about whether those are the same, or whether one could "get out" of one mindframe and keep the other. In any case, there is an interesting set of issues here, and it does indeed affect how one thinks about who one is. I don't recall Orpheus having an immortal head with no body (he was the singer, who's wife Eurydice got hauled off to Hades and who tried, unsuccessfully in the end, to bring her out, no?). May though not know enough of the Orpheus story. Or maybe its someone else? Curious in any case about when/where people begin vesting "self" in head (tracing the literary themes might be the starting point for an interesting web paper).
PG
How so? The leg moving when it is pinched is behavior, no? Glad to have your skeptical eye on the question of whether the "straightforward" is too "simplistic". Hopefully, we won't "overlook all the complexities", but rather see how many of them we can (or can't) account for using a simple foundation.
PG
Yep, it does. So what kinds of observations would incline one to believe thought is in fact in the brain? And, while thinking about that, its worth also thinking about whether we actually have any observations that say it is NOT in the spinal cord?
PG