Biology 202
Neurobiology and Behavior
Spring 2002

Forum Archive - Week 5

We've discovered that signals can indeed start in the middle of the nervous system, that neurons are each little computers, and that there are both excitatory and inhibitory signals. Does that change how one thinks about behavior? the brain? the relation between them? What new issues does it raise?


Name:  Paul Grobstein
Username:  pgrobste@brynmawr.edu
Subject:  week 5
Date:  2002-02-21 08:15:58
Message Id:  1101
Comments:
You've got web papers due next Tuesday, so maybe you're a little preoccupied with that and so the forum will be a little slow this week? Don't worry about it if you're feeling hassled. On the other hand ... by all means write if you feel like it.

We've discovered that signals can indeed start in the middle of the nervous system, that neurons are each little computers, and that there are both excitatory and inhibitory signals. Does that change how one thinks about behavior? the brain? the relation between them? What new issues does it raise?


Name:  miranda
Username:  mcwhite@haverford.edu
Subject:  neurons=behavior
Date:  2002-02-21 09:38:34
Message Id:  1102
Comments:
Knowing that neurons can initiate signals brings up some interesting points. In some ways, it seems to disprove that brain equals behavior. The brain itself is not the sole cause of behavior. For example, if I put my hand on a hot stove, I will remove my hand before my brain has processed pain. However, I believe that Professor Grobstein said earlier this semester that when he says brain equals behavior, he really means the entire nervous system equals behavior. Thus the equation still stands.

There is one problem I could see with the possibility of signals starting in the middle of the nervous system. There are so many neurons in one's body that it could be possible for signals to interfere or send conflicting messages. Thus the nervous system is much more complex than were there one autonomous initiator of action.


Name:  Rebecca Roth
Username:  rroth@brynmawr.edu
Subject:  Neurons
Date:  2002-02-21 23:54:28
Message Id:  1116
Comments:

The brain's ability to perceive, think, remember, and control actions and emotions is based on an intricate set of connections---10 billion neurons. Our understanding of how these neural connections develop is going to change as long as more research is being done. The brain, which is composed of these individual neurons, are controlling our mind. The brain evolves to shape itself. While looking at the web for information on neurons, I came across this analogy--"Perhaps the brain is not like a computer, but more like an orchestra, with billions of neurons cooperating to produce the symphony we call thought." Just another way of looking at the brain. To even begin to understand the function of nervous systems and the organization of behavior is extremely complex.

Isn't it true that when you hear something new you grow more dendrites to reach other neurons? If that is true, the more you practice, the stronger the neural connections become. Since most neurons receive information from other neurons and then pass this information along, so could that be received at any part? How exactly does the brain work? What is the relationship between the brain and mental functioning? Is it the neurons in the brain that are firing and allowing us to become the people who we are?


Name:  Cindy Zhan
Username:  qzhan@brynmawr.edu
Subject:  
Date:  2002-02-22 12:22:31
Message Id:  1118
Comments:
during the lection about action potentials and resting potentials. I all of a sudden realized something. If it takes time for reaction to occur, and the act of listening to prof grobstein in class is a reaction.Then it takes time for us to "hear" prof grobstein. WHen sound is coming out of the lecturer, our brain takes in the sound wave and process them so we can make sense of what the sound mean. All of that takes probably many many action potentials to accomplish. say that each action potential takes 1m/sec to occur, then there is a possbility that from the time the sound came out of prof grostein to the time that the student actually "hear" and undertand what he is saying, fractions of a second, or maybe even seconds had passed. . .

i just though that is this so cool because before realizing this, i always assume that speaking and hearing occur simultaneously. like someone was talking to me, the moment the sound came out is the moment that i heard the sound. It's strange becuase even if it is true that speaking and hearing does not occur simultaneously, i will never "feel" that time had passed between the too actions. but then again. . . "feeling" is deceiving. . . right?

-Cindy
Name:  cass
Username:  cbarnes@brynmawr.edu
Subject:  
Date:  2002-02-24 22:43:48
Message Id:  1134
Comments:
If a neuron can fire in the middle of the nervous system, that is, without input, then to me, this is thinking.

This would not necessarily include the environmental stimuli that prompt us to think. For example, a sunny day makes me think about the beach, and therefore, I decide to go away. But, if I think about a person with whom I had an enjoyable time with, I may think that I want to write them a letter. These are not actually inputs that create one to think and therefore have some kind of output. But this may not make sense if all thoughts are based on memories or what is in front of us, or our imagination. One could just as easily say that streams of consciousness and thinking about the past or about physical objects is input. But what about dreams? There is no input except thinking. But that could be disputable since there are so many different theories for dreams. If they are just random firings of neurons to keep the brain somewhat active while asleep, then firing of neurons causes thinking and behavior (ie sleepwalking). But, if dreams are present to “figure out” waking experiences and hash out problems or anxiety, then you can’t argue neuronal firings create behavior because the firings would be a correlation to thinking.

One could say that the neurons firing create a behavioral response. But, that is a bit too scientific for me. I would say that when one thinks, it happens to be that the biology of the brain goes along with it. But that doesn’t make sense either because if there is a deficiency in a part of the brain, the neurons gone, then the behavior changes. So……


Name:  Shannon Lee
Username:  kitsumi12@hotmail.com
Subject:  spontaneous thought
Date:  2002-02-24 23:45:06
Message Id:  1138
Comments:
So if the neuron can spontaneously excite and inhibit on its own then behavior can be produced with no outside stimulus, which furthers the idea of brain = behavior. Neurons signaling in the middle of the nervous system can be thought of as thinking I suppose. Sometimes ideas suddenly occur to me or I start thinking of something that was not on my mind. Is this due to the sudden firing of neurons or were these new thoughts subconsciously brought about by another thought or outside stimulus? What causes a particular neuron or set of neurons to decide to fire and produce a new idea, or recall a memory, or ponder something, if a previous thought or stimulus does not cause it? These are all questions that I am confused about at the moment. Thoughts and ideas most often seem to flow based on something that was being thought of before or some stimulus changing the subject of thought. However, there are times that thought seems to be spontaneous.
Name:  Balpreet Bhogal
Username:  bbhogal@brynmawr.edu
Subject:  
Date:  2002-02-25 13:05:33
Message Id:  1147
Comments:
When we think of the brain=behavior hypothesis, we refer to the brain and the entire nervous system. So, if a signal does start in the middle of the nervous system, it still follows the brain=behavior hypothesis.

I also wanted to reemphasize Cindy's point about taking time for action potentials to reach the brain. I thought that was a very interesting point she brought up. We know that it takes time for action potentials to reach the brain; a good experiment would be if we measured the time it took for one to respond to a color appearing on a computer screen. You would probably find that it takes time, although probably not that much time, for the person to respond to it. But the action potentials are extremely fast when you think about it. So, as Cindy pointed out, although it probably takes time to "hear" Professor Grobstein, that time is probably worth milliseconds.




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