Biology 202 Neurobiology and Behavior Spring 2003

On self-control, pain, gender, and ....

On the subject of prodigies, we have discussed how genes and the central pattern generator come into play. After watching the movie "Rain Man" several years ago and discussing autism in class, I wonder how an autism patient is affected so as to display a certain talent. My brother has a high-functioning form of autism (Asperger's), and is an amazing pianist. No matter how much I practiced, I could not match his skills. I wonder then, is it more the central pattern generator that causes him to be a musical prodigy, or is it another factor related to autism?

OK, now on to what I was originally going to talk about. I am doing my second paper on hemianopia, a phenomenon that most frequently occurs after a stroke, in which a lesion on one side of the brain causes the person to lose the opposite field of vision. Not lose sight in one eye, but actually LOSE that side of things when you look at them. So, for example, one woman only put lipstick on the right side of her mouth; give someone with this disorder a plate of spaghetti and they will eat the right half of it and swear up and down that they ate it all. This disorder is sometimes accompanied by complete paralysis of the half of the body opposite the lesion. The reason I'm talking about this in the forum is because both of these disorders are often accompanied by anosognosia, which is a disorder that seems to have causes similar to those of the phantom limb sensation. In anosognosia, the patient does not recognize their paralysis or visual neglect. They insist that they are moving their bodies normally, even while they are lying perfectly still. In one case a woman SWORE she was touching her doctor's nose and kicking her leg, when neither her arm or leg were moving at all. PRETTY STRANGE, I think. So, like with phantom limb, some people think this is just plain denial of the condition; the patient doesn't want to admit their limb is lost, doesn't want to admit they are paralyzed. BUT, a theory similar to the one that Dr. G talked about last class with phantom limb holds up with anosognosia. A motor signal goes to the target muscle but at the same time goes to a monitoring area (apparently in the parietal lobe, I'll cite this at the bottom). The brain gets no return signal from the targeted limb to tell of its position, and the patient doesn't register on that half of the body visually. BUT, the monitoring area has gotten the motor signal, and thinks the motion has occurred normally. So the brain can't distinguish intent from action. The conscious image of the self is just plain wrong. So, could this or something like it maybe occur without a lesion?
OK, even stranger is a different, less frequent phenomenon that can also occur with hemiparalysis. This one is called somatoparaphrenia. Patients with this disorder insist that the body parts on the affected side belong to someone else (most frequently the doctor, just because they're there). Maybe this is for a similar reason; if the visual information (an unmoving limb) given to the brain conflicts with the motor information given to the monitoring area, the motor information is trusted before the visual info (this would make sense, the visual world more frequently offers us illusions not to be trusted, right?).
Sorry for the length of this, but I think this is really interesting stuff, especially in relation to the phantom limb discussion.
I got most of the info for this from http://dubinserver.colorado.edu/prj/mos/osgood5.htm
this is a grad student project, has a lot of good info on just plain phantom limb stuff as well

"When a lesion is made such that an adult animal loses sensation from a particular area (by removing regions of the skin or ablating regions of the retina), the region of the cortex innervated by these missing nerves loses its input. However, after being silent for weeks, this cortical region becomes active again, being innervate by other axons, often from those adjacent to the lesion. Axons sprout from the neighboring nerves, and some pre-existing synapses, which had been below the activation threshold, are now activated (Darlan-Smith and Gilbert, 1994; Das and Gilbert, 1995). With the inhibitory active axons removed, these other axons can function. This reorganization of the sensory cortex is thought to be responsible for the "phantom-limb" pain, the pain perceived to be at the end of a limb that had been amputated. Here, the intensity of the pain is proportional to the amount of cortical reorganization seen in scans of the patients' brains (Flor et al., 1995). Thus, the brain has reorganized itself after the injury such that neurons that were responsive to the missing inputs become responsive to remaining inputs. Even the adult human brain is able to reorganize due to changes in sensory activity." http://zygote.swarthmore.edu/axon6.html

I really enjoyed hearing a possible physiological reason for the sensations that are felt by a person that experienced pain after a limb was removed. I think that society can easily accept this explanation because they can try to 'fix it'; as opposed to a psychological explanation that society would not accept as readily if at all.

Some other sites I found of interest were:
http://www.macalester.edu/~psych/whathap/UBNRP/Phantom/homepage.html

http://www.farabloc.com/mUBC.html

on the other hand, i suppose these limitations would be the ones that show when we are have more than one pain at the same time and we only feel one at a time. still, i think there must be synapses firing in those specific spots (where the pain is being felt).

other than the truly physical pains we feel, the stomach gives me alot of trouble here, because we feel all kinds of emotions in our stomach. if the brain held all sensations, why would we feel negative emotions like guilt or fear or anxiety in our stomachs? there are some that i definitely feel in my brain, like euphoria for example, i can almost feel the synapses firing during euphoric sensations, so why doesn't all our emotion get felt there?

i suppose the answer to that question is because we need to distinguish our emotions from one another. cordelia says that pain and pleasure would each have their own set of neurons and axons and synapses, and if they did, i don't think we feel anything in our stomach, they could all be distinguishable in our brain. i think many sensations we feel come from the same source, and go through the same circuits, but are distinguished by context (and then travel to different places like the stomach or a wound, etc). did we know what it meant to be hungry before we ate something for the first time and felt a satiation to the pain we had before eating? no, we just felt a general pain in our stomach, that could very well have been ameliorated by comforting hug from our mother (if it had been anxiety--as it was the hug would have done nothing). we learn to distinguish the same sensations from one another, but we are still not perfect at it. we may feel hungry if we are depressed. eating won't make the hunger or the depression go away, but we still feel that urge. pain that feels pleasurable is learned as well. an athlete will enjoy feeling a burn in his or her legs after a good run, it will feel euphoric, while the same circuit may trigger that pain in a different context and promote anxiety or just extreme discomfort.

To me this demonstrates that in extreme conditions a person can control just about anything. Even a burp can be controlled, and this control is what separates man from the beasts. We are able to organize and direct our attention to specific tasks. I like Shanti's idea of a super-human defined by their level of control, because it is demonstrated to be true in everyday life. It seems as if the more control you have, the better off you are. The ease with which I can admit this is terrifying in its implications. Are we really moving towards a mechanical future where humans ape machines in their cold, calculated actions? Or is there a tenuous thread of hope to be found in the erratic nature of our free will?

One part of the discussion that really caught my attention was how women are known to use "like" more than men. Now maybe its just me, but it never crossed my mind that people who speak very slowly and with lots of "ums" and "likes" actually use the word unknowingly because they have been natured and nurtured over their lives to be not necessarily sure of the facts because they realize that others will disagree, and thus they wish to not step on anyone's toes by being too assertive.

A point she made was how a room full of women can have a dialogue that respects each others feelings, letting others in on their thought process and willing to mold their opinions according to what they hear. But when you insert even one or two men into that crowd, they tend to be overconfident and dogmatic in their views.

Now I am aware that at times people use such discourse particles because the person is unsure of the proper sentence formation, with their thought process being slower then their actual rhetoric. Studies have shown that the more time a person takes before to plan an answer before responding, the fewer number of likes they will use, assumedly because they will be or at least seem more sure and definite about what they are saying. Even so, this is a very intriguing notion to the discrepancies between men and women. Amazing how such an insignificant word can actually spark such a discussion.

Proprioceptors and corollary discharge circuits could play a very large role here. It has been very enlightening for me to realize that we aren't in fact in control of our own perceptions, and that it is these perceptions that inevitably at least partially lead to our outputs and actions. It sheds new light on the whole serial killer thing for me...but that's a whole other can of worms.

So maybe I should be more sympathetic towards guys...maybe they really just don't get it the way I do. That's what I've gotten from all of this.
I do think we can all understand each other...but it may be necessary to consciously reshape our perceptions. As much as is possible, anyway. That could be instrumental in solving all kinds of conflict in the world.

Of course what can and cannot be controlled by the I-function is also very crucial. Is it only what one would call a sort of low-level behavior like heartbeat or eye movement that we cannot control? Or are the implications much greater than that?

I was also intrigued by the "like" discussion. The desire to undermine ones views and seem less self-assured is a phenomenon I've often wondered about. It touches me personally because I seldom do it, and the results often confuse me. Ever since high school, people have complained that I think I'm always right. That can't be further from the truth, and I think that anyone who has ever taken enough time to understand my mannerisms realizes that. But as I've investigated over the years what it is that makes so many people react that way, I've narrowed it down to my speech. I don't usually attempt to sound as if I'm unsure of my opinions, because I often know exactly what my opinion is. That is not to say I think it's absolute truth, and everyone should agree -- only that I'm sure it's what I think. (If I'm unsure, I say so, and I don't get a negative reaction.) Apparently, this is a threatening or otherwise offensive way of speaking. But why?? If one holds an opinion, shouldn't one simply state that opinion without jumping through verbal hoops to convey that one isn't insisting that that opinion be universal?

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