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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.
Do you think differently about behavior now that we know something about neurons, and if so, how?
Really pleased by the wealth of perspectives/information provided by the web papers, most of which are already posted here (thanks to your commitments to web skill development).
And ... we're through (pretty much) talking about the properties of neurons. Nice lead-in in class today: there MUST be something more than bags of saltwater with variably ion permeable membranes; could be other some other properties of neurons or something about how they're combined at higher levels of organization. Before we go into that, though, it might be fun to revisit the last question you wrote about here: is there anything about behavior to be learned from studying the properties of individual neurons and, if so, what might it be? We hadn't yet talked much about properties of neurons when you wrote about that question, and now we have. How have your feelings on the matter changed (you can look back at your earlier answers). Do you think differently about behavior now that we know something about neurons, and if so, how?
Or maybe revisiting the old question might not be fun? An alternative would be to browse one or another of the newly posted web papers, and write about how it relates to the old queston, or to your own paper, or to other things that have been on your mind. Or, as always, you can write about anything else that this week's classes made you think about.
From looking at neurons, we can also see that signals can be changed inside the brain by how much neurotransmitter is released at the synaptic cleft. Also, signals can stop inside the brain, for example when an action potential reaches the end of an axon and stops because there’s not enough current to depolarize the postsynaptic element. Does this explain how I can memorize material for an exam, then promptly forget it? Is this the “in one ear and out the other” phenomenon? Also, since action potentials are created anew in each neuron (depending on a summation of all inputs), we know that each individual neuron is an opportunity to change or stop a signal. Since there are 1012 neurons in the brain, there seems to be an inconceivably large opportunity to change a signal from the outside, or to start or stop a signal. How does this happen in an orderly manner? When each individual neuron adds or subtracts all inputs from hundreds of other neurons, and that signal gets passed on to be added to hundreds of other signals, it seems to me that the output/behavior is random. Who’s in charge here?
Our discussion of the anatomical specificity of neurons helps with these questions, but also raises other questions such as, why doesn’t the signal from the outside world (i.e. thunder) determine the signal produced in the brain? If the meaning of a signal in the brain depends solely on the line carrying it, then I have some questions about whether any sights, sounds, tastes, smells, exist at all. If we can taste Beethoven and hear a sunset, then what of “objective” reality?
Our study of the properties of neurons has also led to other concrete conclusions which influence the way we think about behavior. For instance, the concept that it takes time to think comes from an examination of the basic properties of neurons and action potentials. Also, understanding that an action potential is triggered due to the sum of many synaptic potentials gives us a picture of neurons being linked in webs rather than chains. This vision of neuronal networking leads us easily to think about larger brain structures and about neurons functioning as groups, which will very likely give even greater insights into behavior.
The final aspect of neuronal function that greatly influences my feelings about behavior is the idea that a behavior is usually the result of removing an inhibition rather than an actual excitation. This view changes the perspective from which we look at almost any behavior.
i am unsure of how the past few weeks of class have affected the way i think about behavior. i have been taught basic biological psychology many times over and it is impossible for me to look at the information presented in class with a fresh view. these are subjects i have been thinking seriously about for almost three years now, so i will share some of my current thoughts, although not necessarily stemming from this class in partiular.
i am a proponent of the emergent mind hypothesis. as a biopsych student, i think of behavior molecularly, but i cannot discount the idea of mind, soul, etc. as beyond the brain. i believe it is a property that emerges as a result of exactly the neural fuctioning we have been discussing. if for no other reason than adding a little mystery to life, than this is what i believe.
in previous classes, i have dissected brains of a few different organisms. to talk about a molecular level of the brain and then to see it as whole, tangible object that can be held in one's hand is an awe-inspiring thing. i most interested in helping people, so i often see the brain as a puzzle. manipulating the puzzle works on all levels in the brain, but seeing and touching such a complex piece of equipment is a powerful feeling. being able to go from ions and neurotransmitters to the brain as an organ is a a challenge i hope we soom face.
From the Egyptians to the Greeks various scholars had their own explanation of the brain and how it works. No matter how ludicrous it might seem to us today, I find it fascinating that people believed what scholars told them. Plato’s theory of the brain is a prime example of this. Since he thought the brain produced semen and “flowered” the female, men were thought to be dominant and women were excluded from most activities. Imagine if this was flipped our society might have been totally different. The faith we sometimes have in science and scientists theories is fairly strong. Today I believe we are in a much more proof oriented basis, were we are trained to be somewhat skeptical of what others say. Back then I don’t think they had that opportunity.
Another important point made is that in order for progress to be made individuals need to be curious enough to explore and find answers to the unknown and not allow faith alone in higher powers and beings be the explanation.
Science made the brain interesting but philosophy kept the interest going. Descartes’ claim to fame, or at least one of them was the saying “ I think, therefore I am”. Descartes’ philosophy as Mridula stated is called dualist because he claimed that the world consists of two sorts of basic substances--matter and spirit. Matter is the physical universe, of which interacts with the body but can, in principle, exists without it. It is interesting to think of the implications that these ideas have on brain and behavior, in relation to what we are discussing in class.
I was also interested to read the part about the impact of endorphins and can attest to the fact that I feel much better both physically and emotionally after a long jog (although I also like Cameron's endorphin release of choice-laughter!)
One question that I had about Cameron's paper, or one thing to think about is the multiple roles that optimism can play on health and recovery. I think that in addition to the impact that attitude (optimism vs. pessimism) can have in terms of the capabilities of the immune system (positive thinking--Cameron's focus) there is also the point that those who are optimisitc have better heatlh-related behaviors. They adhere with the medical treatment at a higher rate and just take better care of their body in terms of such things as exercise and nutrition. Just a thought to add on...
I was at home last weekend and while watching TV I came across a TV movie from a book that I read in eighth grade- Flowers for Algernon. Basically, this doctor develops a technique that can change a person’s intelligence; therefore a mentally disabled person can be put on the intellectual par of a non-disabled person using this technique. However, there was a glitch in the procedure; after a while the effects of the technique reversed and the person went back to their own “natural” intelligence level. I was interested in the science of this whole technique and the possibility of this actually happening- both of which of course were glazed over in the movie. It seems impossible- way more so than repairing spinal cord injury. But I was more interested in the human aspects of this story. This man had a terrible time adjusting to his new life after this technique to subsequently have all of this supposed progress ripped away from him in the end. It made me wonder if he were not just better off being left alone. I do not see what he went through as progress. It is more an ethical issue than a biological one- a pattern that I increasingly see within my viewpoint of the sciences. I can see that others in this class are considering very human questions like these in their papers- like the effects of art on underprivileged children and just thinking positively.
It was interesting to learn that women suffer from SAD with three times more frequency than men. Also that light exposure affects serotonin and people with SAD cannot effectively regulate its levels and, therefore, crave carbohydrates to increase those levels.
My question now is, if this disorder follows a seasonal pattern (with an onset in fall and disappearance in mid spring), then what happens if it gets really sunny and warm for a few days in the middle of winter? Does the person feel normal again just for that time and then fall back into depression when normal winter weather returns? I guess so if it has to do with melatonin levels... affected by the amount of light present.
I'm also curious to know exactly how many people suffer from this (I don't know how many people the researchers Laurel mentioned were able to interview on the subject). Certainly a lot of people around here complain about feeling down, having less energy, etc in the midst of winter gloom, so how many of them are suffering from this Seasonal Affective Disorder?
Overall, very interesting and informative!
To mix up matters just a little bit more, I have the the term "neurons have a mind of their own" stuck in my head. Now, since we learned that neurons do not necessarily have to be stimulated from an outside source, it dawned on me that what we perceive, touch, feel etc might not even exist. So how can a "normal" person (ie someone like a psychiatrist) judge what is reality and what is an alternate universe in his patient's mind. Aside from this, we've all come to the conclusion that everyone's brain is different, so in this case, how could we define normal. In our society, we define words and terms by their opposites- black versus white, good versus bad. But under these conditions where neurons can be affected from internal sources, how does that make us re-evaluate our world?
In conclusion to the neurons having a mind of their own. We learned about the changes in permeability and the ion flows that occur to bring about action potentials and resting potentials. The activity of neurons is the same, it just depends on the location and linkage of boxes. I find it weird that they play such a passive role in that the physical changes carried out are so deatched from the purpose. In other words, the neurons have no idea why these physical changes occur. This leads me to want to construct some kind of hierarchy within the nervous system, separating the actual physical function from the importance, amount of control and purpose of the brain, spinal cord and boxes.
Since Thursday, when we discussed that nerves can be crossed and a person could then see thunder and hear lightening, I have not stopped thinking about this. It's fascinating. It is not the actual structures used to detect the senses, but the parts of the brain that the signals are sent to that are important. Can there be a sixth sense? Or maybe a seventh or who knows how many others that exist in certain regions of the brain, but do not have any connections to the outside world? Maybe a part of the brain would be able to function as an additional sense, but there is no way that signals can be sent to it. If somehow another sense were located, would it be possible that by attaching either the optic or auditory nerves to this location of the brain, the new sense could be manifested?
In this example the behavior of identifying colors by name is the same in most people but the brain setup can be different.
My second query has to do with the "more for removing inhibitions than excitory purposes" aspect. There are many chemicals that are very effective at causing changes in brain and behavior for their removing inhibition properties and now I understand that is true becuase they are working with the neurons own "desire" to act this way. Alcohol as mentioned before is definetely good at "seemingly" removing a persons inhibitions toward social scenes, or reckless behavior and this is a direct reflection of how the chemical ethanol effects the chemical signals in the brain. This chemical affects the neurotransmitters in several areas of the brain to increase activity in removing inhibitions and allowing many more signals to pass that are normally regulated. This increase activity and allowed activity of normally "controlled" activities in the brain can account for the dizziness a drunk person feels, the desire to speak everything on ones mind, or even in extreme cases to commit a behavior that the person "knows" is not right (the control over what paths the neurotransmitters remove inhibitions or excite has been overridden by the chemicals in alcohol) Another direct reflection of what happens in the brain is projected in behavior.
As cool as the whole seeing thunder and hearing lightning thing sounds, I'm not sure I understand it completely. So let me get this straight: we're saying that neural signals are basically the same, and what imparts meaning to them is their location, i.e., where they end up, right? I know you said that just as we do differentiate between different kinds of sounds and sights, we will then also be able to differentiate between them if our cranial nerves were crossed, only we'd see different tones of music and hear different shades of colors, etc. This is difficult to digest, because we seem to be saying that blue could be a sound, and all it would take to make us hear it is some simple-sounding neurosurgical meddling. So blue could then also be a smell, a texture, a taste? Is there anything that is characteristic of blue that is its own intrinsic property, not subject to our scalpel in the way that it will be percieved? I think of blue as a particular range of wavelengths of light: so as i understand it, this idea does not change the fact that it is a range of wavelengths of light, right? All this means is that the wavelengths of light induce neural signals that find their way to auditory areas in ther brain, and we hear the color? So how would blue sound? If it is the rate of firing that makes the distinction between colors or between sounds, etc, does this mean that every color that we recognize to be a distinct color invokes a characteristic rate of firing? If so, how do these characteristic rates for colors compare with the characteristic rates for sounds? Can we chart a relationship between the two, i.e., can we equate a certain wavelength of light with a certain decibel of sound? Are we saying blue could smell like a rose if the rates matched?
Also, this seems to imply that we can see with our ears and hear with our eyes, which seems a little counterintuitive. Are we saying a blind person, with terrible optic defects, can chose to sacrifice hearign to regain sight? Could you recieve auditory input and translate that into visual messages? Can we see flavors without the input ever going through our optic lenses? Has any such animal research been done? Are there any people that actually have some sort of networking mix up--it doesn't sound too impossible--that see sounds and hear sights? How do their perceptions compare with ours?
It all sounds so subjective (i realize we were supposed to leave that word alone for now, but i can't help it). It seems really amazing that we all can agree that something is red or high pitched or sweet. How can we ever be sure that we're looking at the same thing, and understanding it to be the same thing? I remember learning in a psych class that some ethnic groups, which don't have a name for the color say blue, will note no greater distinction between blue and green than between two shades of green. Seeing is believing takes on a whole new meaning.
I not only learned about sleep paralysis but also more about the process of sleep. One thing I found interesting was how the brain sends out signals to the body during REM to control muscle contraction so that a person's body does not re-enact the dreams. It is during this phase that if a person wakes up, he or she feels paralyzed and can not move. In this case it can be observed how the brain is behavior. For instance there was the example of how the man with REM sleep disorder behavior acted out his violent dreams.
As I worked on my paper on OCD, read Hiro's paper on sleep paralysis, and in light of the class discussion on neurons, it struck me on how it does seem to be true that the brain is behavior. It seems that many behavioral problems can be at least partly attributed to chemical imbalances within the brain. I find myself, although still a little hesitant, leaning towards an agreement with the statement that the brain is behavior.
Since writing my paper, I, as most people, have realized that the brain does equal behavior. Or atleast, that is what most scientists are presenting it to be. Although there are experiments validating the role of the environment in affecting a person's behavior, the underlying statement in most of the studies that I read for my paper was that the brain affects all behavior.
When I read Christina's web paper, I was especially curious to read about the effect of art on an underprivileged child. I had heard of this premise before and did not understand the data supporting this until this paper. Her webpaper evidenced that the environment is not negated in behavior. Rather it affects the brain, which in turn affects our behavior.
I also think that this example of alcohol exemplifies the profound importance of the role of drugs in research with neurons. Without the ability to use drugs to disturb the normal homeostatsis of the nervous system, it would be difficult to conduct research in this area. Another example I can think of is the bzd's, or antianxiety drugs. Is it justified to use these drugs in order to decrease anxiety so that we will "function better" under stress? Does functioning differently under stress as a result of a drug neccessarily mean that we are "functioning better"? Who decides what "better" means? The same issue arises with anti-depressant medication and bi-polar subjects. Some of the most creative, intelligent people in the world were manic depressive and only manifested their genius in their manic phases. If they had lived today, would their creativity be normalized in a wasteland of prozac?
So many more implications of and problems with this crossing exist that I am content that for the time being it is not a possibility. However, thinking of the brain in this way has made me more convinced that, in a sense, the brain is all there is. While there are certainly signals coming in from the outside world, what makes our world the way that it is to us is where and how the brain processes these signals. Realizing how different, say, our perception of "sky" would be if things were switched, I see that the brain does, in a very strong sense, make oir reality.
now, we have discussed about difference between visionary and auditory images, and said that the spots in the brain which process the information are different. is that the only difference? i think not only the place in the brain but also the organization of the neurons are somehow different in various spots in the brain. and, the difference in the organization causes the information to be processed as vision or sound.
back to the lightening and thunder issue. i am little confused about this. i understand that if we cut the nerve cords from eyes and ears and switch them, we "hear" the lightening and "see" the thunder. what i am not sure is: how do we "see" the thunder? does that mean that when we hear a thunder, the brain processes it as a vision and create a image of lightening in the brain? or do we see something really different?
in addition to the difference in the processing places in the brain, i think that vision and hearing are different because of the different receptors. eyes are designed to capture light. ears are designed to sense the sound wave, which vibrates the ear drum. don't they have important roles in vision and hearing even if their nerves are switched?
The other interesting question that occurred to me from this "crossing" notion, was whether the functional sections of the brain are developed as a person grows, or whether they are there from the very get go. If they are developed as the individual grows, would a crossing of optical and auditory functions in a baby actually produce a child who "heard" with the eyes, and "saw" with the ears? I guess that the idea of a completely different sensory apparatus shouldn't be that surprising. Different animals brains (bats for instance) probably have entirely diferent ways of processing the incoming information.
