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Neurobiology and Behavior, Week 9

Paul Grobstein's picture

Welcome to the on-line forum associated with the Biology 202 at Bryn Mawr College. Its a way to keep conversations going between course meetings, and to do so in a way that makes our conversations available to other who may in turn have interesting thoughts to contribute to them. Leave whatever thoughts in progress you think might be useful to others, see what other people are thinking, and add thoughts that that in turn generates in you.

As always, you're free to write about whatever thoughts you add this week. But if you need something to get you started, we're started looking at boxes bigger than neurons, and associated cables, beginning on the motor side of the nervous system.  What new ways of thinking about behavior/psychology come from adding reafferent loops and the I-function to central pattern generators and corollary discharge?  What questions remain, and/or newly arise given these observations/concepts?

BMCsoccer01's picture

Tug of war: Mind vs. Body

I really found Sam's previous point interesting that there is no central authority in the brain. Yes, we have components of the brain like the cerebellum & hypothalamus that try to bring some of the divisions of the brain & its capablities in unison, however, the body & the mind are disconnected, while still being connected, as Sam pointed out. The fact that when we get stressed out our bodies are stressed was a new avenue to explore. We are never always fully conscious of everything that our body is doing.

For example, taking the topi of stress a little further, when a woman is stressed out, this could delay her period. Now, is her brain stressed & saying to the body: Nope, not your time yet for an egg to drop." And, if this is occuring, girls certainly don't walk around thinking it all the time; in fact, they may not even realize that they're stressed until their time of the month is late, further proving that their dail thoughts were not emboding the fact that they were stressed and therefore could miss a period.

I guess the ultimate question is: who wins in a tug of war: the mind or the body? Can the body will the mind to do something, just as the mind can have a direct effect on bodly functions, or is it only one sided and the mind holds both sides of the rope already?

hamsterjacky's picture

habitaution and pain

Can a person who lives with chronic pain become habituated to it - can the pain not be felt later on due to its constant prescence?

I had a friend who had an ankle inflammation which caused him constant pain - doctor misdiagnosed him in the beginning so they didn't treat it properly. I remember in the beginning, he limped a lot but later on he started to walk normally. Does that mean that he became so used to the pain that he didnt realize it was there?

The body generally points over very well when its not happy - such as with pain, but at the point when the body no longer sends pain symptoms, can it be thought that the body had in essence, given up, about the pain and moves onto larger harm?

Also, what about how we really feel the pain when its there and its short term, or acute, but we can't really describe how it felt later when we dont have it. Does this go with the theory that the body tries to erase those memories that aren't pleasant?

mmg's picture

Cultures and set points

Last class brought up a lot of interesting points. I thought about the idea that our cultures are getting homogenized. To a certain extent, I feel that it is possible. I am a Bengali, and I know a lot of Bengalis that grow up outside of West Bengal or Bangladesh that speak the language of the place they grew up at. When language is not enforced at home, it is lost. With geographical location changes, the cultural validity of a place is in certain ways altered or lost. Having been brought up an Indian though, I find myself leaning towards experiences that have elements of my culture in them in this country. (Eating food that is closest to the kind I am used to back home, loving crowded places, etc). In a certain way, my brain is typecast into my culture. Even if I were to spend the rest of my life in other countries, I will still keep looking for these elements. In that sense, heterogeneity is not lost. I wonder though, to what extent can the brain still hold on to one culture, and how much of it depends on the age of the person? Genes probably have a role to play too.

I find the idea of the I Function as a filter put forward by drichard very interesting. It helps me make a lot of sense of what the I Function is about.

Also, I wonder whether evolutionarily, humans should have come to a set point which is the most conducive to their healthy functioning. Obesity is a problem, as earlier noted, and having a high set point is not beneficial to the person because of the risks it has. Is it possible to arrive at lower set points for humans? I know we discussed that there are certain advantages to having a higher set-point, but it seems as if a lower one is far more beneficial. I also wonder about the anthropological significance of different set points in different cultures. How much of it is culturally related? How much is dependent on environmental conditions?

Anna Dela Cruz's picture

Emergence As Presented By PBS

So in thinking about the lectures on week nine I was particularly struck by the idea of order arising out of chaos. In biological systems we see examples of, for a lack of a better word, spontaneous order all the time. Ant colonies, schools of fish, and even humans (as evidenced by the eye sore of a dirt path bisecting Merion Green) were mentioned in class. To gain a further understanding of "order out of chaos" I recently watched a segment from NOVA Science Now (link provided below, by the way why can't we upload a video onto the blog?) on emergence, which apparently addresses the idea at hand. Several points I found interesting:
  1. there are no leader/follower relationships
  2. instead of top to bottom order, it's bottom to top
  3. behavior of the whole is more than the sum of its parts
  4. while often seen in living systems, a computer program was able to shed light on emergence (more on this later)
  5. complexity level in processing information is directly affected by how connected parts are to each other
  6. one neuron of the human brain connects to 10 thousand other neurons (so yeah, we're pretty complex creatures!)
  7. molecules of pyruvic acid (a very simple compund that could have been abundant during early Earth) when put under the environmental strains present during Earth's infancy rearrange themselves in water to form vesicles. is this how life began?

The computer program (used for playing checkers) mentioned above shed light on the idea of "order in chaos" because after many games it began to favor programed moves that were proven to be more efficient in winning the game. After a while, it even beat the programmer at his own game. The scientist interviewed for the show brought up the idea that following simple rules leads to learning, a form of complex processing. Could the computer program be an electronic model of our brain?     


shikha's picture

neural networks

Absolutely! In fact, there are several computational models of the brain. This field of study, a subsection of AI, is called neural networks. Basically these are models that attempt to imitate the individual neurons and the vast connections they form with each other (the network). The sort of learning the network does (supervised, unsupervised, reinforcement learning, etc.) depends on the algorithm that is chosen. Computational neuroscientists also use these models try to understand the mechanisms for neural processing and learning. Although these models are simplistic and are not able to completely model the very complex human brain, they do provide some insights into how the brain may function.

Glad you brought this up!

(I'm excited because I'm writing my thesis on this :) )
fquadri's picture

Week 9

Like others here, I’m wondering where individuality fits into all of this. We all have boxes of various sizes that communicate with each other to produce outputs that help us interact with the world around us. I understand that specific inputs will create certain outputs for everybody; if everyone in the classroom was pinched on their hand, their hand will immediately pull away. I’m starting to wonder if a huge chunk of individuality is embedded into emotions, and how much emotions affect reafferant loops or other future outputs …. Sure everyone will pull away from the source of the pinching, but some may hit back after pulling away and some may pull away by moving their whole body as opposed to just moving their hand. Also people will feel differently about it. Some may be angry and want to confront the source, others may be angry but not confront them, some may be confused and want to know why he or she was pinched, and others may just be shocked but move on. What accounts for such variation? Can we say it’s because of genetics, nurture/environment, both, or something about the I-function?

aybala50's picture

2 different brains

What stuck with me after our discussion in class was Ilja's worry that diversity in this world disappearing. The way I can make a general border for diversity is by using different countries. Though I understand that some countries are more similar and some countries are more diverse than each other, for arguments sake, I want to talk about people from different countries. Ilja, I think, talked about the world economy becoming more homogenized which increases the interaction between nations, which in turn creates a more homogenized culture.

I don't think that I can imagine the whole world turning into one culture, but what struck me was that this could possibly happen on a smaller scale. What I mean by this is coming from personal experience. When I lived in Turkey I had a completely different mind-set about life experiences. After I moved to the US this opinion of experiences, the way I experienced life, changed. The reason I know this is because I realized that now I almost have 2 different brains that I can switch on and off with will. If someone asked me a controversial opinion question my answer would depend on whether I am thinking about it as a Turkish person, or whether I'm thinking about it as an American.  

bpyenson's picture

Set (, Match?) Point(s)

So, I was especially intrigued last week when we were discussing how the neuromuscular (and other systems) may in fact run as feedback loops that seem to have a 'purpose' by virtue of their set point that seems to drive the function towards some kind of end. In addition, what intrigued me was the change in set points: how that happens, why, and at what rates.  With that notion of recursion in mind, I have a few issues that I'd like to discuss.


1. What about the existence of a foundational (and universal?) set point?

Is there some default set point, such that a system can revert to that value?  The analogy I'm thinking of is with evolutionary systems (i.e. Steve Jay Gould's notion of evolution of complexity/ 'drunk-man's stumble'), where Gould argues that complexity arises through short bursts of complexity that are NOT directed towards some goal (e.g. complex morphotype), but instead arise through the overcrowding of a very simple niche.  This notion goes against a directed notion of evolution (e.g. natural selection) and instead implies that evolution of complexity can occur through too many simpler forms.  The important thing about this analogy is that the simple/basic is seen as the foundation and goal, NOT the teliological quest for complexity/ progress that we would probably assume would be the goal of evolution.  If this notion applied to the nervous system, it would seem that our perspective is all wrong about the set point being the purpose, when in fact the purpose might be something else.

2.  The definition of 'purpose' raises a lot of interesting issues. 

a.First of all, why are we defining the 'purpose' of the nervous system as some implicit teliological goal?  Couldn't the purpose be the rate of change of the set points, not just the set point itself?  I guess my closest analogy is with particular morphogens during development of embryos.  The morphogen's method of action is NOT just the concentration but the rate at which the morphogen's concentration changes.  If the change is drastic enough, then a resulting change occurs in the phenotype, but if that rate of change threshold is not achieved, then no change results.

3. Could the set point be a strong enough factor in the nervous system such that the loop changes directions entirely based on the set point change?  For instance, we were assuming with examples such as anorexia that the negative feedback loop keeps getting more negative with a change in set point.  But, could the set point be independent enough/strong enough driver of the system that it could switch the whole system in another direction (e.g. positive feedback loop) instead?

redmink's picture

Thoughts on Muscle Movement.

Since we have been talking about the motor neurons and movement of our body in class, I was thinking of the relationship between the muscle movement that does not involve I-function and the external cue from the environment.  Their relationship has been proven in the book called Power vs. Force by Dr. Hawkins.

In the book, he states that he discovered the human body instantly responds to the truthful/untruthful statements by muscle testing.  The method of this testing is that a right-handed subject holds his/her left arm (the weak one) and is asked to resist while pushed down by a partner.  The partner says something true or false and then see how easily the arm goes down when pushed.  The result reports when true statement was made such as “my name is ____” the arm stayed relatively firm, whereas false statement was made such as “I was born on Mars!” the muscle became weak and is more prone to pushed down further.  This proves that the muscles are responsive and sensitive to subtle statements without the involvement of I-function. 

So, I am convinced that even without the I-function we can still behave and most of our behavior made throughout our life is from subconscious/unconscious.  I found it very interesting.

I hope to learn more about how our learning can be made without the huge involvement of I-function.  I had believed that the learning process of our brain starts from our reinforcement or strong I-function.  For example, planning out the exam study schedule or what to ask in class, etc.  However, I realized that the best learning can also made from a new sensation, or shocking experience that the brain had never been exposed to:  a new observation.  We’ve mentioned about this in class in which our brain, when introduced with something new (or unexpected), learns.  I think this aspect of learning also involves the big role of unconscious/subconscious part that does not involve I-function.  I am surprised bit by bit whenever I realize the importance of the role of the unconscious/subconscious.

I recently watched the performance of Yu-Na Kim, a gold medalist of The 2009 World Figure Skating Championship held at LA.  Her every single movement was perfect on ice.  Starting the skating since the age of 11, she has repeated practicing and made mistakes (falling down more than 1000 times per year).  I wonder if her I-function is turned on while she is on ice and make double accel. Jumps and so on.

ddl's picture

Differences in Motor Function

The discussion about the differences in motor skills for certain functions between different groups of people (old vs. young, male vs. female, practiced vs. unpracticed) raises several questions for me.  We’ve already discussed how our behavior is most likely linked to the structure and signaling between the various neurons within our nervous systems.  If this is the case, in terms of explaining these perceived behavioral differences, are there specific identifiable trends within the structure of two people’s nervous systems who perform a given activity in the same way as one another?  Do things such as age specific structural tendencies within the nervous system exist which cause certain groups of individuals to generally excel more so than others at different activities?  Presumably, such structural patterns should underlie/account for varying observable degrees of efficiency with regards to the execution of motor function activity.  Also, on a related note, do those individuals who are more practiced with certain activities develop more efficient neuronal pathways for that activity in similar ways which separate them from those who are less trained to perform such tasks?   Or is it the case that the patterns of interconnectivity and amount of their neurons within these individual nervous systems exhibit no distinguishable similarities?

jwiltsee's picture

Set Points and Sleep Paralyzation

The concept of set points seems intriguing, almost impossible for my to fathom.  I understand the general concept, but like you said in class, if you found out how they are set and/or change you could win the nobel prize.  What I can't fathom is where would these set points even take place.  In cells, in the nervous system, in the brain, or in the muscles.  What makes them the set point rise when one has a fever and how is such a medicine like tylenol supposed to help against fevers(i.e. lower the set point back to normal?) And it seems like there could be hundreds of these set points in ones body to keep it at homeostastis.  

A few times throughout my life I have been awoken during sleep, i am conscious, but my body does not respond to my desired action, similar to a state of paralyzation.  Why is it that my brain is awake, but my body is not.  Why are the corollarry discharges not able to move my muscles when my brain is sending signals for movement.  There is no splice in my spinal cord, so is it just simply my brain is conscious and my body is alseep, and how can one be awake and the other not.  It is not like when u sleep on ur arm and it falls asleep from lack of blood flow.  My body is stuck.

Adam Zakheim's picture

Thoughts on set points

I also found the idea of homeostatic, set points interesting. If people have naturally occurring set points with in there nerves that regulate both conscious and unconscious actions, then it seems were are getting closer to the brain = behavior idea. In thinking about psychosomatic conditions, it is possible that a person can unconsciously alter these set points to produce palatable, physical illness? Considering ideomotor and ideosensory automatisms (where patients feel and behave in a way consistent with an implanted idea without reflecting on its sensory plausibility), is this “implanted idea” a set point that has been altered? Or, is this a more conscious decision?

ilja's picture

randomness and individuality

Our discussion about set points and motor movement brought up the issue of control and individuality. I wondered how we can have control over what we do if there is no “coordinator”? If there are set-points determining how your behavior is formed and a degree of randomness associated with our actions? It is hard to imagine the brain working without relating it to yourself, without thinking of it as something that you do and have control over. I feel I should be able to change my set-points and should be able to influence my learning.

After this class though I started thinking about individuality differently. What if these ideas about randomness of behavior, the unconscious part of our learning and coordination within our brain would actually account for our individuality? Following the Harvard Law of Animal behavior it might be that the coordination between different parts of the body, the fact that we do not have one place for movement but several, actually accounts for diversity. The unpredictability and influences of all the different factors gives an individual the freedom to explore and expand on what he/she knows. Since nothing is set in stone, and since we learn through experiencing new things and comparing the inputs with the outputs in our reafferent loops we create our individual selves. Could the unconscious learning, the inputs reflecting the outputs instead of taking away control give us the freedom that we need to behave “as we damned well please”?

drichard's picture


In light of our studies this week, I propose that the I-function could be a filter as opposed to a box. Inputs and outputs could run through this filter, defining the electrical signals as individual-specific. For example, the signal for "pain in arm" is edified and turned into "the specific pain in MY arm" when run through the "comb" of the I-function. This filtering process is performed on signals which the nervous system can alter through reafferent loops. For example, the "specific pain in MY arm" might be due to a splinter stuck in my skin. The I-function allows me to realize MY pain and MY ability to alleviate it by removing the splinter. Unconcious actions, or actions that are not outwardly claimed by the nervous system as "mine," such as breathing and blood circulation are not run through the I-function continuously because they exist inside the body and are not influenced by reafferent loops in the same way.
kenglander's picture

filtering through the information

I like your idea of the I-function as a filter or some sort of mechanism that can be switched on or off. As bkim points out, some actions that are not actively monitored by the I-function can be brought into consciousness when one is primed or prompted to think of these functions from some outside source. For example, blinking is considered an autonomic function that people rarely think about. However, if something or someone in the environment primes you to think about blinking, you will inevitably become more aware of when you blink and when you don't. You might also alter the amount of times you blink by shortening or lengthening time between blinks. I'm curious about how and when the I-function comes into play as a filter and how much it is based on input and the environment. I'd also like to look at how the I-function relates to decision making and how it has the power to redirect actions (if it does at all). In other words, does the I-function have the power to sway how we interpret input and therefore ultimately affect our outputs and responses?

Bo-Rin Kim's picture

This notion that the

This notion that the I-function is a filter rather than a box is an intriguing one that makes a lot of sense to me. One reason why the I-function may be better described as a filter rather than a box is that, unlike other boxes, it does not produce any output on its own. It works through other boxes, filtering and channeling signals down different pathways depending on if the signal relates to an awareness of the self. The I-function, therefore, can be part of several different pathways. Describing the I-function as a filter gives it more flexibilty. It is not a box that is always part of a certain behavior pathway, but it is a filter that can be taken our or put back in. For example, the pathway that causes people to perform some kind of engrained, habitual behavior, such as biting their nails, can occur with or without the I-function. It is the same behavior of biting nails, but it can occur with and without the person knowing what they are doing. The I-function can distinguish between this kind of behavior one is and is not aware of. However, I do not think the I-function can distinguish between voluntary and involuntary behaviors, as these separate two distinct sets of behaviors. Involuntary movements include things like digestion, heart beating, etc. Voluntary movements include walking, talking, eating, etc. The I-function distinguishes movements within the voluntary category. The same behavior can be projected differently through the I-function filter to make the person aware or not aware of their behavior. Thus, the I-function is a filter that can be placed in or taken out of a pathway.
Sarah Tabi's picture

How does individuality play a role?

With all of this discussion regarding different aspects of our nervous system such as reafferent loops, basal ganglia, motor cortex, etc., what causes individuality in behavior?  I think that one of the major foundations of behavior is the fact that every person is inherently different, therefore their behavior is different.  What we covered so far in our discussions are our body's responses to various external and internal inputs/outputs.  But my question is, how would uniqueness come into play with understanding more about the motor aspect of our nervous system?
nafisam's picture

In class, we discussed the

In class, we discussed the example that if the motor cortex is damaged, the I-function loses its ability to control body movement, but the nervous system still has control over the body. I have always considered the I-function a distinct and somewhat superior entity to the rest of the boxes because it is the box that in some ways shapes our identity. But the fact that the nervous system can compensate in the absence of the I-function adds more layers of complexity. Does the I-function exist only to prevent our nervous system from functioning in certain ways at specific times? Is the I-function merely an inhibitory signal of the nervous system?
Leah Bonnell's picture

Motor Skills

In class we discussed how young children do not have fine motor skills. Also a result, children are not able to do some tasks like button a shirt. I think the concept of motor skill development is directly related to speech development. Children cannot produce some sounds and words because they lack muscle coordination. The timing of language development seems to be dependent on motor skill development. 

I wonder if motor skill development occurs during a critical period like language. If a child was prohibited from moving during the period when motor skills usually develop, would they have normal movement as an adult?

People who play sports or an instrument from an early age tend to be better. Is this just practice, or could there be a critical period involved?



SandraGandarez's picture


If all of our movement are coordinated by motor symphonies, then what are muscles spasms, or involuntary twitches? Are they just mistakes by motor neurons or signals? And why do people's knees give out or buckle? Did their muscles just give up or get a signal to stop supporting your weight? It seems like the whole issue of walking and coordination of our bodies is a lot more difficult than I previously anticipated. After all there are many actions where our bodies make involuntary movements, or at least subconscious movements that we do not anticipate. Just because your knees buckled does not mean that you've damaged your motor cortex, right?

Lisa B.'s picture

Week 9

Do genes make us fat? Some of our class believed that weight is a set point, but I disagree with this. I believe that making this statement ignores the obvious issue at hand. Obesity is a problem in America. Genes may cause weight gain in some people, but the majority of people simply lack nutritional education. Calories in vs. calories out have nothing to do with genetics, but the culprits of overeating are often not controlling fat intake, snacking, emotional eating and exercise.

Emotional eating would be an interesting discussion to have as a class. Why does a person eat comfort foods to maintain good moods? Can our box theory explain this dependence? I would also be interested to hear the class opinion on the use of sweet treats for child behavioral reinforcement. Does this encourage these children to continue this behavior as an adult and never learn to deal with the sad feeling?

bbaum's picture

After talking about motor

After talking about motor control in class on Thursday, Iwas wondering what the differences were between the precentral gyrus and theother parts of the brain that control muscle movement like the medulla, thereticular formation, etc. In class we learned that when you stimulate the otherparts of the brain, a coordinated movement occurs, but when you stimulate themotor cortex, there will be random movement in the area that you havestimulated, but that movement will be uncoordinated and random. I always thoughtthat the parts of the neocortex are more sophisticated then the lower parts ofthe nervous system. Why is it that an area like the medulla, which is usuallythought of as a primitive part of the brain can make someone walk, while theneocortex, which is supposed to contain amazing things like morality and reasoncan’t even produce a coordinated movement. I’m guessing that because mostcoordinated movements do not required the I-function (walking, picking up anobject, etc.), the I-function may not be located in the “lower” parts of thenervous system, but rather in the neocortex. Because it takes extra steps toscreen stimuli through the I-function, it may be necessary to give theresponsibility of movement to the parts of the brain that do not require theI-function to function. 

jlustick's picture


I was interested in expanding/further exploring Tuesday's conversation on set-points in relation to hibernating animals and human body weight. Prof. Grobstein suggested that set-points may be responsible for humans being overweight or underweight- that obese individuals have a higher set-point and their body's desire to maintain this set-point makes it very difficult for them to lose weight. There seem to be several problems/questions with this conception. First, why is it so easy for most people to gain weight? Perhaps the set point is not an exact number, but simply a physical state-for example, one of excess weight or having a drive to gain. In contrast, anorectics may have a set-point of being underweight or having a drive to lose. Perhaps a person could be classified as someone who either "stores" or "burns." But that can change... overweight individuals have become anorectic. What explains that shift? In addition, people who are normally "burners" are often able to gain weight for pregnancy (although they may gain much less than someone with the tendency to store). How much control do I have over my set point? It seems that eating/exercise habits may be partially rooted in the subconscious (for example, emotional eating or individuals who just cannot get the motivation to exercise), so maybe the set point is embedded in that part of our brain. Therefore, individuals who decide to lose thirty pounds are only changing their conscious set point. How might one change the unconscious? What is the purpose of the unconscious set point existing? Why would it be evolutionary advantageous?

I'm wondering if set-points might play a role in other areas of homeostatic regulation. For example, mental states like happiness or depression. Might people have a sort of mood set-point? Does medication change that set point or simply ignore it? Perhaps only therapy, which might bring the unconscious into the conscious, can actually change the set-point.

 Finally, what does the idea of set-points say about the mind-over-matter suggestion? Do we have more control over our physical selves than we imagine or less because we need access to our unconscious to achieve this control?

Sam Beebout's picture

body and self

I really like the new observation that there is no central source of authority in the brain. Thinking about the brain as a coordinated system does make more sense. I'm really interested in the impact of the body on one's mood and one's sense of self. Ideally everything in our body is connected, and I think that everything is in communication, but we don't need to be conscious of all of it, and we don't always realize that we are conscious of it. Although Christopher Reeves still had his I-function I would guess that losing access to his body also dramatically altered his sense of who he was. This seems obvious because his was a dramatic case, but we are also always conveying ourselves in many ways simultaneously. Our body language is a double reflection, sometimes an opposing expression, of what we are putting out into the world. When we are stressed out, our bodies are also stressed out, and vice versa. Its not that any of this is a new observation, but I am just realizing how seeing the body as a divided between many authorities in conversation with one another makes our sense of self a dynamic and often uncontrollable. 

Percival52's picture

Where is the I Function


I agree that we concluded that the brain lacks a central authority for all the actions that the brain produces. However, we said that the Cerebellum acts as a comparator for reafferent loops and the Motor Cortex turns off older patterns so new ones can develop. So there isn't a central authority there are relative rankings of importance. I think this relative ranking is important when contrasted with the I function. We can use the I function to change the set point temporarily, as in the case with a person on the diet, but never permanently. I think it is bizarre that if one realizes that something pre-set, the fact that knowing it isn't enough to reset it the set point. I mean if the I function uses reafferent loops and corollary discharge to learn, then why can't the leap from unconsciously re-setting the set point to consciously re-setting it be made. What is standing in the way?

BeccaB-C's picture


I thought a lot about learning today while sitting in my organic chemistry class, a ~60 person class, taught in a lecture hall, in which the professor writes reactions on the board, students copy them down, and then process them on our own before our exam. While I was certainly not as active in my participation in the class as I am in an this class or in an English class, both of which are far less based in particular contextual frameworks, I feel very strongly that, as students and as humans, we interact with our environments all the time. Engagement with the environment can be retermed one's simple existence in it. While the CNS involves and engages itself through the reafferent loop in which it makes adjustments to expectations, this is not to say that human interaction is as cut-and-dry a process.

I guess this gets me to a little bit of the "mind as a construction of the brain" controversy, but I would venture to claim that it is our minds, directed by the homeostatic adjustments in expectations in response to the environment, made by the nervous system, that engage with the environment, with our without active or conscious engagement. This includes the hypothetical brain-dead individual who, while not actively interacting with the environment, and living in a simple state of reafferent, homeostatic looping signals, engages with his or her environment through the affects he or she has on other people, parts of his or her pre-brain-dead environment, etc.

Brie Stark's picture

Earlier in the week, we

Earlier in the week, we were discussing reflexes and how they were produced.  A thought that came to mind is reflexes that a child is born with but eventually grows out of (like the galant reflex).  I was wondering how reflexes eventually become 'voluntary' functions, and if it was applicable to the mechano-receptors we had been talking about on Tuesday.

The question was also asked if there was a "force" for diversity in the brain.  I find it ironic that no hierarchy/leaders are present in the nervous system.  However, as far as we know, humans have worked with a social structure since the age of the neanderthals.  Perhaps our community of neurons doesn't translate their community into our social behavior; it is merely for structural convenience and doesn't permeate into how we behave socially.

eglaser's picture


We spent much of today's class talking about movement and how different parts of the brain control movement. This sparked a thought, I have a friend who sleepwalks, and when I saw sleepwalks I mean that she has actually left her house befoer and started walking along the road. She usually is carrying out some common activity such as getting ready for school, or she is trying to prevent something from happening (in one situation she was trying to go downstairs to turn off the television because it wouldn't turn off in her dream). In either situation she goes through very complex movements and situations, all while asleep.

How does this play into what we already know about movement and the brain? We have established that you do not need the I-function to have movement (even complex movements) but when a person is asleep shouldn't that prevent movement? Why do some people sleepwalk and others do not? How does all that we know about movement explain sleepwalking?