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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.
Central pattern generation, corollary discharge, action as a "motor symphony", reafference, and genetics are among the things we've discussed in the past two weeks. In what ways have one or more of these gone beyond action potentials, synaptic potentials, and so forth in causing one to think differently about behavior?
For my next paper I want to explore the affects of marijuana on the brain. What goes on in the brain when a person “gets high”? What effect does the chemical have on the brain to produce the intoxicating feeling? Are the effects of marijuana at least vaguely related to antidepressant? The fact that marijuana is known to produce “a high” in many people can be viewed as evidence for brain=behavior. But not all people who try the drug seem to get the effect right away, or get an opposite effect not related to the “high” at all. Could their brain be different from the brain of those who do get effected. How? The chemical that is “the chef intoxicant” in marijuana is known as THC (C21H30O2). How could this single chemical produce the various psychological and behavioral that constitutes “getting high”?
Our discussion of the nervous system in terms of “motor symphony” and corollary discharge, caused me to reexamine the cause and effects models of many drugs. These ideas certainly go beyond action potentials, synaptic potentials and so forth. When talking about action potentials one could get fooled into thinking that behavior is in fact the cause, (for example, a neuron firing) and effect (the transmission of the signal to the next neuron) phenomenon. But if one thinks of the nervous system as a “symphony” where every element playes ints role, one realizes how complex it becomes. So could it be possible to track the effect of a chemical when there is no clear path and the players are so intertwined.
But something that really interests me is the comcept of an "anti-placebo" effect. I am not sure if that is the term to use, but the concept is that if someone is going to believe that no, this drug/supplement is not going to work, it wont. I believe to a large extent that this is true, at least for me. I am not sure if there is any better phrasiology for doing research on this topic, or if it is even different from doing research on the placebo effect. Does anyone else find that assumptions can change consequences?
A question: Is it really true, if you think you can, you will, and if you think you can't, you wont?
The paper begins by describing the physiologically based “dynamic stabilization” theory, which suggests that dreaming is caused by “firings of the neurons in the brain [which function to] re-establish a chemical balance.” It then goes on to discuss some of the psychological approaches to dreaming, specifically that dreaming offers an opportunity to explore feelings without acting and without the inhibitory signals present in conscious thought. It is suggested that this can function to “settle emotional disturbance.”
I found this interesting because it seems to relate to the discussions we have had concerning brain and behavior. While dreaming is a necessary biological process, it also seems to have properties which, at first, don’t seem to be explainable in terms of biology. While brain processes may be responsible for sleep and dreaming, what is responsible for the specific content and emotional nature of the dreams? Mary points out that both approaches are scientific in nature because they both rely on observations to guide conclusions. I think this is an interesting point and I wonder if there are any other ways to integrate the two approaches to dreaming. I guess that there is still a lot that we don’t know about dreaming, but I think that it is an interesting topic to consider further.
The more we talk about the nervous system and how it works the more comfortable I have become. It seems to me that things such as central pattern generator and "motor symphonies" explain behavior much better than something as simple as the firing of action potentials in individual neurons. I feel as though these ideas are sufficiently complex to account for the wide variability in the range of my movements and behavior. And the fact that the "motor symphony" can be rewritten by using input from sensory neurons also makes me very comfortable. The idea of a pre-existing written "score" seems very robot-like to me. But by being able to change the pattern as you go a feeling of some control is invoked.
Another thing that caught my attention was that these central pattern generators have lots to do with the genome and with DNA. This tends to make me very nervous because it implies that traits such as those pertaining to violence may be written somewhere in genetic information. I am a very avid believer that people are genuinely good and just. I believe that it is only things such as physical trauma in the brain and mental "baggage" (that people collect from every time they ever felt badly about things that hurt them in the past) that prevent them from acting as though they are good and just. Last semester in biology we were asked the question: Do you believe that the human genome-mapping project will find a genome for a trait such as "murder"? At the time I very adamantly replied no. I believe that society and culture factors are what create the want or need to kill. But now seeing that genetics has so much to do with behavior it seems much more possible to me that traits such as alcoholism and violence might be attributed in part to DNA. This, however, is another example of what I feel is a loss of control or at least conscious choice. I like and want to believe that every human being is essentially good and the thought that a pattern for violence could be somewhere written in me is very disturbing. I would like to look further into this idea and see if there is some way that I can accept it without causing too much discomfort.
I was especially fascinated with the concept of corollary discharge signals, which was just touched upon at the end of Thursday's lecture. In the first few weeks of class when characterizing behavior, we commented that signals could originate within the nervous system box. At that time, I accepted this, but was not quite sure that I understood it. Now, however, after closely examining central pattern generators, I can more clearly see that this is possible and does happen. This new idea requires me to again re-examine my view of behavior. How does one go about targeting the precise location of these signals? We saw that it was very difficult to narrow the search for central pattern generators to a general region of the crayfish, so imagine how much more difficult it would be to accurately locate them in a human. Further, how can a person be treated if these signals are harmful to an individual? The types of medications that I have researched so far have mostly targeted specific receptors of neurotransmitters. This leaves me wondering how defects in central pattern generators are medically approached.
I think that our discussions on the intermediate boxes thus far have been interesting and thought provoking. In order to find answers to remaining questions, I think it would be helpful to examine the anatomical details of central pattern generators thereby allowing us to understand the mechanisms involved.
The idea that some central pattern generators exist as a function of genome expression supports evolution's ability to describe certain aspects of behavior. Certain CPGs exist prior to sensory information and can be traced through related species. (The fact that they can be traced does not amount to a proof of their existence, though.) What is perhaps more important than explaining behavior, certain individual CPGs demonstrate that evolution can shape patterns of behavior in addition to shaping anatomy.
Nevertheless, I would like to see some sort of principle that organizes the Central Pattern Generators. The book describes the brain's role in regulation, but there are still levels of randomness present. Understanding CPGs is a step in the right direction (towards abstraction and unification of different forms of behavior) in the quest to explain behavior in terms of the brain, but we should not be absolutely convinced. Maybe the type of evidence I am looking for - neurological patterns that give a clear description of "the self" as a first principle" - does not exist or cannot be found, but a claim that all of behavior can be reduced to brain-stuff m
The idea of a central pattern generator intrigued me because of my experience with dance. A few weeks ago, I wrote about a pianist would could still play songs that he had learned years ago, even though he had not played the piano in quite some time. That is not dissimilar with my experience dancing, particularly tap dance. Certain repetive movements somehow have stayed with me for years. I wonder if central pattern generators for creative endeavors such as dance are also stored in the spinal cord, the way walking is, or if the complexity of movement requires a different place for storage.
When speaking of central pattern generators, it was suggested that the implication of their existence negates the concept of a soul. I personally do not see the rationale for this conclusion. Assuming that there is a 'motor score' does not, in my opinion, refute the existence of a soul or 'higher self'. As much as physical/motor action may have a predetermined pattern generator, higher cognitive functioning dictates when and perhaps why that pattern generator will be elicited. So, it seems pattern generators are secondary, and must be 'activated' by a precursor. I see no reason why this precursor cannot involve what has been referred to thus far in this course as a soul. This precursor may also involve the intangibles that have yet to be explained such as free will. It seems too simple to say that a central pattern generator is the end all be all which dictates all of our motivations, aspirations and behaviors in general. Along the same vein, to say that motor action has a pattern generator does not mean certain thoughts or thought processes have pattern generators. The inputs and outputs occurring in our 'heads' (those outputs that do not display a visible behavioral response) may very well be random in the sense that they are made up as we go along. This may or may not be the case, but at this point, it seems premature to make any assumptions.
The whole idea of central pattern generators introduces some other tangential (but interesting) queries. From what I understand so far, there are certain motor scores in living creatures that are predetermined (i.e.-independent of past experience and present in the earliest stages of embryonic development). If this is true, does this mean that, to an extent, certain things are preordained or destined to occur? I have always thought of fate as something which is not mediated by the individual's 'conscious' effort or involvement and CPG's seem to fit or at least compliment this description. It may be a silly question to ask, but it seems that many of the behaviors that characterize species may be in part mediated by central pattern generators. If these are predetermined and in a way out of the control of the individual, the existence of CPG's could imply an almost fatalistic influence…
I think it makes sense, though, to think of CPGs as secondary, and to realize that there are other methods of control and invention going on in the nervous system. Even though we have been cautioned not to think of the brain and the spinal cord as two separate pieces of the nervous system, there does seem to be a hierarchical organization to it. The textbook discusses the idea of hierarchical and parallel functioning of the way in which the brain affects CPGs, though the parallel functioning seems less clear to me. Just as the concept of CPGs draws on the “smaller boxes” of the individual neurons and how an action potential is generated, there are things going on in the nervous system above the CPGs that function based on the existence of CPGs. Although it seems that I always come down to this general thought, I will say it again because it seems to apply: given the breadth of behavior that must be accounted for by the organization and functioning of the individual parts of the nervous system, the existence of CPGs makes a lot of sense. Its almost like it gets the “simple” (i.e. repetitive) behaviors out of the way by encoding them in pre-existing and already specified patterns. But, the system leaves room for the inevitable compensations that must be made due to the constantly changing nature of the external environment and the effect this has on repetitive patterns of movement. I am still curious as to whether CPGs exist for thought. Can a disorder like ADHD be accounted for by the genetically influenced pre-existence of thought patterns, which cannot be changed through learning, because the pattern is part of a “thinking” CPG?
I also keep thinking about what I said in class about Navajo (??) children who spend most of infancy strapped to a board and then when taken off immediately crawl with no coordination or developmental problems, which suggests that the CPG for crawling and possibly walking is already present in humans and that for crawling it is only a matter of growth that prevents infants from doing it. I have been looking for where I read that and I have had no luck - so if anyone else knows what I am talking about - I would appreciate your input.
And relating to the subject of pattern generators and a related topic that we touched upon in class last week, someone mentioned how many types of "animals are born knowing how to walk." I also encountered this week a magazine article that's a variation on that theme in the current issue of "Mothering Magazine." In it there is a story illustrated with beautiful photographs of a newborn human placed upon his mother's belly immediately after birth. This baby employs his sense of smell utilizing the amniotic fluid on the hand he was chewing upon and matches it to the exact chemicals that are secreted by the mother's breast to literally help himself to his first meal. He uses a "push-up pattern," such as babies use to crawl, to make his way unassisted from mom's belly to her breast. If anyone would like to see it please ask me and I'll be happy to share it.
Just as an aside, I was also intrigued by the idea that people only sense what they have sensory neurons for. I know people can't see all colors or hear all sounds, but it was strange to think that maybe there's another kind of sense that some animals have that we can't have and may not even know about. I might like to try to find strange senses that other animals have that are not shared my humans for my next paper topic. I don't know if there is really something as different as I imagine there might be, but the subject really interests me.
The next day, I went at it again, and eerily, I was immediately much better at juggling the clubs than I was when I had stopped the day before. On my first or second attempt, I set a personal record by a large margin. It just seemed to come much easier than it had the day before. It felt like some motor learning had taken place overnight. Like something had become solidified in my brain during the time between the two juggling sessions. I think that I may have generated a central pattern for club juggling. This pattern took some time to generate--according to my hypothesis, some changes took place in neuronal organization that couldn't happen immediately during the first half hour practice. It was weird to be better the second day than when I had stopped the day before, but I'm pretty sure this was the case. Can central pattern generation work like this? How long should it take for these patterns to solidify, Professor G.?
Kim B
The educational psychologist said I was an ADHD boy -- or in the female realm, the tomboy type. By fourth grade I had beaten up every boy in my class, served detention every day, and was even suspended. While getting older did impart some level of maturity, I remained hopelessly fidgety and as my teachers would comment, ever a distraction in the classroom. While I took every honors and AP course offered which I could possibly squeeze into my schedule my grades forever seemed to fall short of my “potential”. Teachers deemed me lazy because of my grand tendency to ace the first page or so of a test (the first 15 mins worth) and then fail the rest when the incessant TICK TICK TICK TICK of the clock -- or the THUD THUD THUD of the radiator would overwhelm me, leaving me absent and disconnected from the task before me.
Testing was suggested at 18 when my SAT scores were of national merit standard, and my grades were of steady Bs. Educational testing noted a discrepancy of more than 50% points between my overall IQ and the examination for the presence of ADHD. Still the range indicated only an average likelihood of the presence of ADHD. I am a positive diagnosis, but not unlike many who have ADHD, over the years coping strategies are developed, particularly if one is of high general intelligence, which helps one live with the struggles that come as a part of ADHD. The decision to take ritalin was not as controversial on the individual level as I deem it to be in the overall societal realm. Within two weeks of medication all of my grades were As and above. Suddenly I could sit through a whole class, or read a book one line at a time (rather than the previous 7 at a time -- which had led to obvious complications). On ritalin I no longer see the incessant stream of subtitles to every word and sound that is audible to me. Thankfully ritalin leaves your system within a matter of hours, and while I enjoy the focus and control it allows for tasks which demand high concentration. So too I have become accustomed to the fidgety hyperactive me.
It is interesting that while we continue to strive to accumulate evidence that brain equals behavior we have yet to discuss any evidence (if there even is any) of there being a soul or a "self". It would be interesting to look at it if there were.
Responding to a comment above about central pattern generators and dance, I too dance and find that years later out of no where I may be able to pick up a routine that I had done once. I have been dancing since two, and "dance movements" seem second nature to me. I always try to learna dance so I "don't have to think about it". It just happens. It just comes from my body and not my brain.
Another topic that came up in the forum that really made me think was Jason's comment about learning to juggle and improving "overnight." I was thinking about whether his hypothesis could be applied to land sports as well. I find that every year I improve my skills with no further practicing after field hocey and lacrosse seasons end. I always hypothesized that the rest over the summer was what did it! But I like the idea of it taking a while for the c.p.g's to get going so one can improve "overnight!"
In response to Kathy's posting, you are correct in speaking about the concept of an anti-placebo. The tecnnical term is actually a "nocebo". I wish I had found enough space to discuss this aspect of placebo effects/ non-effects... I'm glad you brought it up. A nocebo effect is basically adverse effects of the treatment or placebo. For example, when subjects are told that they have a (nonexistent) electric current passing through their heads, 70% report a headache (Turner, "Placebo Effects in Pain Treatment", JAMA, 1994). But, not much research has focused upon negative nonspecific influences such as these. Note, however, the direct connection between placebo and nocebo effects-- is there much difference between believing in a treatment (and it has positive results) and NOT believing in a treatment (and there are no results)?
I am interested in the apparent connection between Bipolar Disorder (less "correctly" known as Manic Depression) and creativity – a connection demonstrated by the disproportionately large numbers of artists and writers who are believed to have suffered with the disorder. The evidence that so many influential artists (Byron, Coleridge, van Gogh, and Virginia Woolf to name a few) were Bipolar lends support to the notion that psychological torment is a necessary part of the artistic creative process. This seems to raise questions as to the necessity of suffering to the quality of human existence. Clearly our existence as a species would be diminished without the artistic "genius" responsible for what we respond to as great musical, literary, and visual works of art. If this genius often grows up in suffering, it seems that the torment of some us benefits all of us. Thus it is possible to ask whether it is really ethical to "cure" or control the symptoms of or even eradicate bipolar disorder with modern molecular biology.
But ethical questions concerning the diminution of the experience of humanity as a whole can seem irrelevant when confronted with the personal suffering of an individual struggling with the emotional agonies of the disorder. Although I imagine there could at least in principle be people who would choose to suffer for the sake of their art or to preserve their creativity, the magnitude of the struggle an afflicted person faces day after day seems one that demands to be eased if at all possible. The problem remains to find a way to relieve that suffering without creating new suffering of a different sort -- most if not all current treatments seem to bring with them undesirable and significant side affects. I am struck by the amount of experimentation (mostly unsuccessful except in determining what NOT to do) that seems to be involved in today’s approach to treating bipolar disorder. This was highlighted in Debbie Plotnick’s midterm essay. I am glad she gave the forum her essay – thank you Debbie. I am very interested in a couple methods of treatment Debbie Plotnick described as being of interest to her daughter Ashley: ECT (Electroconvulsive Therapy) and TMS (Transcranial Magnetic Stimulation). Both therapies seem to be quite affective at stabilizing mood to a more comfortable, less extreme range. However TMS may be more promising if it is free of the troubling side affects of ECT.
An acquaintance of mine has experienced ECT himself for treatment of bipolar disorder. He answered some questions I had about the side affects of ECT. One common side affect is the loss of short term or long term memory. My friend says there is, at least for him, some long-term memory loss. His memory loss does not seem to involve the loss of any skills or abilities. Nor has he lost memories of any very large, significant events or experiences. But there are smaller experiences from before his treatment that are now gone – things that are memorable and should be available to him as they are to his friends and family in memory. Loss of life experience seems a heavy price to pay, but for my friend, emotional stability is worth the sacrifice.
1) In my model, I had suggested that abnormal firing in the visual area of the brain triggered by a strobe light disperses to other areas of the brain. Corollary discharge is a likely mechanism of this dispersion. The visual area does give off corollary discharges as we have talked about during walking. In the case of a seizure, it sends the discharge. Unfortunately, the information being sent is abnormal and spreads the abnormal signal to other areas propagating the seizure.
2) When we talked about carsickness and phantom limb, it was said that there was a conflict between the corollary discharge and the sensory input bringing about discomfort. I am wondering that if during seizures there is also some sort of conflict. At the onset of a seizure, most people describe a period of discomfort called an aura. People with epilepsy know that they are about to have a seizure when they experience aura. This discomfort could be a result of a conflict between corolary discharges of the visual cortex and sensory input.
3) The idea that the input interacts with an individual's corollary discharge pattern and that two people could have different corollary discharges giving rise to a different experiences. So few people have epilepsy (I think about 1-3%) and of those people only 5% have photosensitive epilepsy. This suggest to me that individuals with photosensitive epilepsy have different corollary discharge patterns and therefore have different experiences in response to strobe light than most people because they have different "wiring" in the brain.
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