Neurobiology and Behavior, Week 8

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.  Are central pattern generators, corollary discharge circuits, and reafferent loops helping to begin bridging the possible gap between neurobiology and psychology?

nafisam's picture

At the beginning of the

At the beginning of the semester, I was a proponent of the stimulus/response model, but with this new knowledge of efference copy and corollary discharge, this model is becoming increasingly obsolete. The stimulus/response model does not account for the independence and self propagation of the nervous system, and frankly does not give credit where credit is due. As humans I'm not sure if we spend most of our time responding to inputs from our environment, or if we are just contained within our nervous system and only respond to our own inputs and just keep the reafferent loop going. Is there such a thing as being too involved in your nervous system? Does this account for disorders such as dissociative identity disorder?
Anna Dela Cruz's picture

Biology, Self, and Freud: A Random Rumination

I believe Professor Grobstein said on St. Patty's Day that some aspects of behavior are influenced by genes--central pattern generators, language. This idea of having inherited some of humanity's biological success stories (and even perhaps some that are not-so-successful) made me think of Sigmund Freud's quote "anatomy is destiny". The quote has since been expanded to "biology is destiny". What are the implications? Does this mean that even in the way we identify ourselves, biology is not only an influence but is also the primary cause? Neuroplasticity says that everyday experiences can change the way neurons and therefore, regions of the brain interact with one another. This physiological change can then change the way a person thinks. Now, I'm not all too familiar with the works of Freud. I just know that he was a psychologist, physiologyst, and all-around authoritavive thinker.  
bpyenson's picture

Valuation in Efferent Copies

One question that continues to perplex me from last week is the idea of the conductor-less corrolary discharge/efferent copy.  I understand that there seems to be no central organizer, but in fact several groups that coordinate the action of the whole (distributive organization). 

 

In thinking about how this system may work operationally, I began to wonder how well defined the small 'command centers' or pseudo-conductors were in relation to one another that were, in concert, coordinating the corrolary discharge.  In other words, we seemed to say that there was a distributive system, assuming that each node was of equal value to the system as a whole.  While Dr. Grobstein said this is true, that no one dominates another in terms of control of the system, couldn't it still be true that each node is entirely identical to each other one?  I suppose I am skeptical of the replicability of each node and want to believe that there exists some sort of variation (be it genetic or phenotypic) of each node that could provide variation over evolutionary time.  It might seem that the systems NEEDs to maintain this nodal identity if we are to assume that life ever achieved complexity in evolution.  From evolutionary theory, we think that variation in development (through phenotypic plasticity) could be exploited by natural selection to create adaptation, and ultimately speciation.  [See the work of Bryn Mawr's resident paleobiologist, Dr. Bruce Saunders on ammonoid suture complexity in evolution to learn about the evolution of complexity.]Assuming that each node is or could be unique, then it seems that some nodes would be inherently more valuable for the corrolary discharge than others.

Also, it seems that we assumed that the node (presumably at the level of a neuron or a few neurons) was defined.  This could explain why we would assume that each node could be equal to one another if they all exhibit many of the same properties as each other.  Nevertheless, I think it's important to question at what size level we define a 'command center' in the corrolary discharge so that we can better understand each node in they system.  Is the definition one of function (e.g. as soon as an area is able to stimulate an output it is a node)? or is the definition more arbitrary (e.g. a neuron or 3 neurons)?

Max86's picture

Metaphorical Thinking

I going to take a potentially crude course and point out that there seems to be a general pattern for our class posts. I see two types of questions, which generally follow a concrete routine. The first type is a sort of scientifically focused question that posits the subject of our discussion as a potential solution to a specific neurological disorder. The second type of question expresses itself as a sort of macro-metaphor for neurological activity that links societal patterns and group behavior to internal biology.

The first type of question seems firm and tenable. However, the second type comes up a bit in this class, and I wonder how credible or productive it is, especially since I'm apt to enjoy these sort of humanist reflections as a literature student. For example, Jlustik's meditation concerning the desire for social hierachries as a reflection of absent (or egalitarian) neurological order strikes me as just the sort of metaphoric appropriation of the material that I myself am inclined toward. 

My question now: How legitimate or conducive to insight are such meditations to the sciences? If you read a text like Heidegger's "Why Poets?" you read that verse has a purpose: Namely, to reach out into the abyss of an arbitrary and inherently meaningless existence and articulate something ineffable in such a way as to fortify onself against the "desolation of the world's night."

Now, this sort of language strikes me as profound and inspiring, but can applying it to neuron patterns really elicit greater insight into human behavior on a rigorous, scientific level? I suppose one answer is that it might inspire or drive a scientist to think differently about a given task or observation, but this is still subordinating metaphoric thought to scientific progress. The whole point of constructing metaphors is that there is no point - poetry and literature exist as their own referent. That is, they aren't designed to convey a definite meaning, but rather to exist as objects in their own right. I fear that my conceptual reception of microscopic activity is fundamentally non-productive to a scientific discourse; I fear it converts the content into an ineffable and mystic example of language as heroic impotence.

Anybody have a response to this? 

Paul Grobstein's picture

sciences/arts/humanities/the brain and relations among them

Maybe you're drawing too sharp a line between the sciences and the humanities/arts?   And perhaps underestimating, ironically(?), the activity of the humanities/arts?  

"The whole point of constructing metaphors is that there is no point" seems inconsistent with you describe as the "purpose" of verse (and other arts/humanities?):  "to reach out into the abyss of an arbitrary and inherently meaningless existence and articulate something ineffable in such a way as to fortify onself against the "desolation of the world's night.""  Perhaps the "point" of both sciences and humanities/arts is to explore possible meanings in an inherently meaningless universe and, by materializing them in some form, contribute to the ongoing evolution of possible forms of existence?

If so, then, as Ben suggests, one might find a continuing, valuable, and bidirectional interaction between sciences and arts/humanities.  Maybe the "conceptual reception of microscopic activity" is always potentiallly productive for scientific discourse?  And, conversely, the descriptions of "microscopic activity" may often contribute to possible new conceptions of meaning?  Always recognizing that neither has permanence?  And hence that language and other acts of communication among people are always incomplete? 

Maybe what you call "heroic impotence" is actually a feature of the human condition that provides the room and possibility of genuine and continuing self-definition and redefinition? If so, then, according to Emily Dickinson, that "herotic impotence" must be a feature of the brain?

For more along these lines, see

bpyenson's picture

Science, Humanities, and the Liberal Arts

Hey Dr. Grobstein and Max,

My main response is to Dr. Grobstein's interpretation of my response as arguing that there exists a true "bidirectional" relationship between the huamnities and sciences, and that in fact, they are disciplines with the same end goal in mind.  While this attitude is attractive, I do not believe it to be true, as the sciences maintain more intelligibility due to their strong operational applicability, which the humanities must often stretch to argue for their relevance, I think.

Although I would like to be the optimist that believes that all disciplines are created equally, my own feelings on the issues suggest otherwise.  While I think that much constructive discourse can emerge from a blending of science and the humanities, I think it still remains salient to remind oneself that each discipline offers different contributions, of which I would argue are NOT all equal to intellectual progress.

I guess I am a proponent of the hierarchy of discourses, and do believe that some of the 'harder' sciences (e.g. physics) maintain more legitimacy in the general field of exploration, than the 'softer' sciences (e.g. anthropology).Not to say that I am not a fan of much anthropology.  Quite the contrary, I find much of the work in sociology and anthropology to be as or more illuminating than work in the natural sciences.  However, the work in the discipline is NOT subjected to the same standards of rigor that chemistry and physicists must adhere to, and therefore, is open to more criticism and doubt, I think.

See Jean-Francois Lyotard's book, The Postmodern Condition, for more discourse on these issues of the hierarchy or lack thereof of the sciences.

bpyenson's picture

The Purpose of Non-science for the Scientist

Hi Max,

 

I'll try to address a few of your stated issues here.

I think you are correct in asserting progress of the poet that literature and the humanities serve a vital (maybe the most vital...) role in articulating meaning from nothing.  Indeed the best psychological analysis of Hamlet will never suffice for a live acted viewing of Shakespeare's work, in the same way that I think a knowledge of astrophysics doesn't make Orion's belt appear any brighter.  Isn't that the appeal of the humanities and (I'm hesitant to make the leap) the arts?  They have no bounds for grounding their observations among a league of restrictions in which the sciences must be bound. 

 

My experience of doing science is akin to that of writing.  I like both for the reason that good science and good writing force you to make order out of the chaos of observations/ideas that you've assembled.  The scientist must support statements with evidence (often quantitative or visually qualitative), while the writer must construct his ideas along the medium of paper and isn't allowed the freedom of a poet to arrange words according to some personal order on the page.  Instead, the creator of the work in both cases must obey some generally accepted (universal?) rules about presentation and communication to produce work.  Albeit in both cases their limitations are different, I think the point is the same in that there are operational rules in effect that limit what the scientist and writer can produce and communicate (rationally) to others.

 

Inherently, as I think a poet like Keats would argue (read the preface/introduction of Richard Dawkins' Unweaving the Rainbow), the humanists (or artists) look upon the sciences with contempt because of the sciences' inadequacy to describe phenomena accurately.  So, in summary, I might understand where you're coming from in thinking that the subjective approach of the artists (humanist?) far exceeds the more (at least purported) objective approach of the scientist in describing phenomena.

It seems to me that you answer your own dilemma, however, when you are concerned later that the sciences treat the humanities and arts as handmaidens: inspiration for more scientific progress.  As I see myself doing more science in the near future, this is much of my approach to the humanities and arts (and gladly so).  I cannot count the number of times insights from courses in philosophy, German, literature and art history have forced me to reevaluate the way scientists traditionally approach the same phenomena.  For instance, I vividly remember doing field work after my art history course on the history of landscape art, and revising all of my typical methods for doing the geology that I would have normally approached differently.  True, I was using the humanities as a servant to my science, but is that unethical?  Couldn't that be 'good', as it applies the work of poetry and art to a practical/operational use?


Further, I think you would probably agree that advances in technology have drastically revolutionized the way art and humanities is done.  Take word processors and the internet for example, without which, this very forum wouldn't be possible.  To close, I would say that the humanities are NOT degraded to the level of 'heroic impotence' as you suggest but instead occupy a role of freedom and creativity unparalleled in the sciences, and territory in which no science should ever trespass.

ddl's picture

Changing Neuronal Connections within the Nervous System

I thought jlustick made a very interesting point about the potential for the pathways and connections of the nervous system to change over time.  It seems pretty apparent to me from all that we’ve discussed thus far that the way an individual perceives, acts, thinks, and behaves, is directly related to his or her neuronal activity (and that this neuronal activity is, in turn, dictated not only by the amount of neuronal units available, but also by their specific and unique linkages to other neurons).  This being the case, I believe that changes in behavior or thought due to things like aging or acquisition of knowledge would also be influenced/accompanied by alterations to this structural composition of the nervous system.  Therefore, I think that if diseases such as Alzheimer’s can be linked to the negative effects of neurofibrillary ‘tangling’ (implying that the ‘proper’ connections of the nervous system’s efficient design have been compromised), that it would be just as likely that a person who is expanding their knowledge (via schooling, studying, or other means) has the ability to improve or more efficiently modify their neuronal connections.  In this way, it would be possible to create more efficient input and output pathways that would ultimately improve the execution of particular functions. 

redmink's picture

Our interpretation of the

Our interpretation of the world plays a great role in determining our behavior.  My experience in culture and education in South Korea where I was born and raised for about 15 years has deeply been stuck in my brain and it greatly affects my behavior even now.  For example, it feels rude for me to talk a lot in front of people who are older than me, and having lots of body gestures feel not ‘right’ to me sometimes based on my culture I grew up.  How I had been interacting with people in Korea greatly shapes my behavior even now in America. 

BMCsoccer01's picture

Was Dickinson On to Something More?

Hey guys, check out this paper. It includes Dickinson's poem  that we were exposed to the first day of class. I think it's interesting to note the difference between the "I-it" and "I-thou" relationship. 

C.G. Janson, White Daisies on My Mind (Requiem for an Alzeihmer Patient). Reflections: Neurology and the Humanities, August 2005. 65; 654-656.   

Crystal Leonard's picture

Tourette Syndrome and central pattern generators

Central pattern generators have got me thinking about certain psychological disorders, such as Tourette Syndrome. The tics associated with Tourette Syndrome can be quite complex and involve multiple sets of motor neurons. For example, the shoulders of a person with Tourette Syndrome might jerk while their torso twists. Or the person might have vocalized tics, such as saying obscenities or repeated clearing of the throat. The movements and vocalizations are not voluntary, so their complexity points to the existence of "motor scores", and thus central pattern generators. Is Tourette Syndrome explained by the dysregulation of different sets of central pattern generators? If so, what is the regulation pathway for central pattern generators in a "normal" nervous system? And what is responsible for the dysregulation in people with Tourette Syndrome?
jwiltsee's picture

directors and patterns

Thinking about the discussion on having directors that can help organize the patterns of neurons, I've wondered about how one would change a certain pattern.  For instance in many activities there is muscle memory that is created over many repetitions of the same thing or from what we talked about in class with motor scores depending on prior experience.  How does one break down a certain pattern in order to change their muscle memory, especially if there are director cells that control the patterns and corollary discharges.  Are these director cells display plasticity, where they are either easily changed or easily replaced.  Also, the other way a motor score is determined by genetics.  If a director is a determined through genetics it would seem as though this director would oppose change since it is hardwired into your cells???   
kenglander's picture

I think your question about

I think your question about muscle memory is really interesting, but I wonder if memory is the appropriate term to describe quick actions and/or responses that occur without activation of the I-function. Could it be that muscle memory is actually just a well-rehearsed motor symphony? That is, could a particular pathway that coordinates a series of actions be reinforced such that it can be activated without consciously thinking about each component?

Changes in these symphonies might occur when the expected results aren't attained. In other words, these motor symphonies could be modified and adapted much like the loopy science model of learning that we talked about at the beginning of the semester. For example, when typing on the computer I do not have to consciously think about my fingers moving to individual keys to spell words. In this case, one might say that there is some sort of "muscle or finger memory" going on when I type because I do not have to activate the I-function. However, if I type the wrong letter, I can adjust my activity and consciously choose the correct key because the previous motor symphony (summary of observations) is not supported by my new experience (making an error while typing). Hopefully I would learn from constant mistakes and these motor symphonies would adjust to improve my keyboard accuracy (readjusting my summary of observations). Furthermore, these pathways would be reinforced if I spelled the correct word, which would reinforce particular activity patterns related to spelling words correctly.  

kdillard's picture

Experience of pain

I think the body's response to phantom limbs is very interesting and brings up many issues about the nature of the nervous system and the experience of pain.  It is interesting that certain boxes connected to the phantom limb are still intact and sending corollary discharge to other boxes in the nervous system, resulting in pain and discomfort.  I wonder why this does not happen in people who have been paralyzed, who still have intact boxes connected to the part of their body that is paralyzed, just like a person with phantom limb syndrome.  Maybe, they still have the corollary discharge but their injury gets in the way of the signal being sent back to the brain, or they simply can not feel its effects.  It is also interesting to think of the role that the I-function plays in the physical manifestation of pain.  Is it possible that the I-function exists in multiple boxes, some of which can be disconnected, in the case of a paraplegic, explaining the absence of pain?  If this is true, then can a person only experience pain if their I-function is intact?
Sarah Tabi's picture

Is there really a bridge with psychology?

I think in some ways, learning about the reafferent loop, corollary discharge, and pattern generators are growing my understanding of some of the more basic aspects of psychology.  But I wonder how these components of the nervous system can connect to more multi-layered psychological occurrences, such as depression, the Oedipus complex, bipolar disorder, etc.
ilja's picture

coordination over one coordinator

Our last class made me think about diversity. About how our body can interpret things differently and the function of it according to coordination and cooperation instead of there being one coordinator. There does not seem to be one “self” once “essence” directing the rest. Then I started thinking about the world and there does not always seem to be this trend in society.

We have the president and the people, we have the teacher and the students. They all seem isolated from each other, not coordinating, assuming to be the knowledgeable compared to the one learning. Why is there this set-up of a “leader” and “followers”? I have always looked for diversity, the more the better, when people start to agree things become boring. This is why I did not particularly like high school, because students were treated as little kids that could not possibly have something interesting to say.

I really like diversity (even if it causes problems, culture shocks, distrust and forces you to move beyond what you know), but sometimes I’m afraid we are losing our diversity. It seems at times that all this sharing of ideas, globalization, making more efficient and productive use of our resources only ends up blurring out our differences. People seem to afraid of their differences and there therefore do not talk about it. Your individuality is your private matter and the better we melt the melting pot together the better. Languages, traditions; diversity, will it continue to exist?

Percival52's picture

Diversity, Efficiency and Learning.

I absolutely had the same idea from our class on Thursday. The world we live in is organized into sections of leaders and followers, teachers and students. We said in class that human behavior doesn’t have a conductor. There are several processes working in conjunction with one another. I can’t remember if we decided that some Pattern Generators are more important then others, but I imagine there is a hierarchy even within our bodies. Diversity is a wonderful thing but the more there is doesn’t necessarily translate into things being better. Looking at the body, there is incredible diversity in the types of cells and chemicals running through our blood but if diversity would be allowed to run rampant then it we wouldn’t be able to function. I think this extends to human behavior. We talked about people walking across a green until a path has been worn into the grass. I think that this type of behavior is shared among humans because it is the efficient thing to do. Efficiency is one of the corner stones of survival and learning is certainly another one. Our society is set up into section of leaders vs followers and teachers vs students because it a good way to learn. If everyone had to learn everything on their own from experience it would take forever to learn something new and any one mistake could be fatal.

drichard's picture

Thoughts on motion sickness, Dramamine, etc.

I read Julia's posts on Dramamine and box-to-box conflict. They made me think about the potential relationship between box-to-box conflict and general stress.

During a bout of motion sickness, the body becomes nauseated as a result of spatial disorientation. The body's balance is thrown off by abnormal movement in the environment. The body cannot ground itself. As a result, the rest of the senses are thrown off and the body focuses itself on relieving the motion and restoring balance. The "pain"of nausea signals the rest of the body/senses that something is wrong. In this way one box (the box or group of boxes attentive to equilibrium) disrupts all other boxes. Instead of enjoying the beautiful sunset or the light sea breeze we put our heads between our knees or take Dramamine to calm our stomachs. Maybe it isn't the brain "choosing" which box to listen to in a conflict. Maybe there are built-in overrides that, when aroused, temporarily cancel out other boxes.

Also, I thought it interesting that Dramamine is a sedative of sorts. The brain seems to have a fight or flight response to high levels of environmental discord. If the action potential for the response is reached the brain elects to fall asleep. This speaks to the brains capacity. It seems that there is such a thing as sensory overload. My question now is, where does this potential sit? How much can the brain take from its environment before it shuts down? There is an interesting dichotomy here, I think. We discussed the need humans have for sensory inputs; these inputs help us retain a sense of self (we spoke of sensory deprivation tanks and their capacity to remove this sense). It seems we need to be grounded by some sensation. However, too much stimulation results in an equally removed sense of self ( in the form of sleep).

aybala50's picture

tricking the brain

After our last class the thing that stuck with me is the idea of tricking the brain. When we were talking about phantom limbs, I started thinking about the way Dr. Ramachandran treat this problem. He would use a mirror box so that the patients could move the phantom limb. (http://endthepainproject.org/images/mirrorbox2.jpg) As seen in this picture the person can "see" the non existent limb and the brain receives this signal and is convinced that the limb exists. Then the person moves this limb by moving the actual arm. Moving the limb relaxes it and the pain is treated this way. 

After this I started thinking about the placebo effect. Though the placebo effect is not always existent, it is a true phenomenon. 

Both Dr. Ramachandran's treatment for phantom limbs and the placebo effect lead me to question Emily Dickinson's poem. If the brain is what creates everything and controls everything, then how is it that it can be tricked?  

Leah Bonnell's picture

Anosognosia

The article about anosognosia reminded me of the discussion we had at the beginning of the semester of Dickinson vs. Descartes. Anosognosia and phantom limbs support the idea that brain=behavior because in both conditions brain damage causes in radical changes in behavior and perception. The article suggests that anosognosia and phantom limbs may come from brain damage that prevents new sensory data to be added to the region of the brain responsible for internal representation of the body. This model makes sense to me; it seems like the cable that connects sensory input to internal representation is broken. I think it is interesting (and scary) that this broken cable overrides the ability to use logic and learn. Patients with anosognosia believe they aren't paralyzed even though all external evidence shows they are.  
Adam Zakheim's picture

repairing the damage....

In considering anosognosia and phantom limbs, I agree that “it seems like the cable that connects sensory input to internal representation is broken.” After reflecting on this idea, I did a little research to find out how broken cables can be fixed. A group from MIT, directed by Dr. Yi Zhang is currently working on axon regeneration through the study of the central nervous system in the optic tract of hamsters. Yi Zhang's research activity focuses on the molecular mechanisms of CNS injury and axonal regeneration and developing strategies for the repair of CNS injury. She is particularly interested in the involvement of cell adhesion molecules in the reconstruction and remodelling following the lesion to the nervous system and using gene-targeting techniques to explore the therapeutic value of cell adhesion molecules in promoting neuronal plasticity and axonal regeneration in the nervous system. In recent years, she has concentrated on the studies on how polysialic acid, a post-translational modification of NCAM, regulates neuronal plasticity, cell migration, axonal guidance and targeting. She has also been engrossed in genetic modification of Schwann cells for cell-based therapy to promote the repair of injured spinal cord and peripheral nerves.

For more information, see http://www.ncbi.nlm.nih.gov/pubmed/17202469  
SandraGandarez's picture

hesitation

Since the boxes communicate with each other rather than having a conductor control their actions, does that mean that there is a hesitation between what the first box knows and what the last box does? An example could be with the swimmerets of the crayfish. If there are 5 swimmerets then it seems logical that the second swimmeret will know what the first swimmeret is doing before the others. My question is if that hesitation in the transfer of information causes a hesitation in action? Do the swimmerets do their pattern on purpose or are they merely acting when they receive a signal, which is later than the previous swimmeret?

bbaum's picture

After Thursday’s

After Thursday’s discussion on phantom limb pain I startedto think about other circumstances when there is loss of feeling in limbs. Themost common circumstance when this occurs in after a stroke when people maypermanently or temporarily loose feeling or control over certain limbs or bodyparts. I wanted to know if a temporary loss of sensation could lead to aphenomenon that has the same characteristics as phantom limb pain, even if theloss of limb was not permanent. I found a journal article that looked at theexperience of anosognosia and other disorders that involve abnormal attitudestowards or perceptions of the affected limb in patients that have recentlyexperienced strokes with damage to the right side of the brain. The researchersfound that about 92% of the stoke patients experienced some type of “disturbedsensation of limb ownership,” and that the patients that did have theseexperiences tended to have specific damage in the right posterior insula. Ihave been unable to determine what the role of this specific box is, but itseems that it is involved in own sense of limb ownership. It would make sensethat if this specific area were damaged, the individual would be more likely tohave a disorder such as anosognosia. I also looked at an article that looked atpatients with both right side and left side damage, and found that there was asignificant increase in anosognosia like symptoms in patients that had rightside brain damage. I was wondering if there was any correlation between theincidence of phantom limb pain and on which side the patient lost the limb. Iwould predict that because the part of the brain responsible for limb ownershipis located on the right side of the brain, patients that have lost a limb onthe left side of their body would experience more phantom pain. 

Lisa B.'s picture

Week 8

What would happen if the sense of the body (vision, balance of organs and proprioception) failed? For most people, the movement of body parts is unconscious. However, there have been case studies of patients suffering from a malfunction of their sixth sense. The sixth sense is our awareness of our own bodies through the sensory flow from muscles, tendons and joints. When the body is not able to sense itself, it must compensate through the remaining senses of the body. One of Dr. Oliver Sack's case studies, "The Disembodied Lady," described a patient who claimed a need to consciously control the movement of her hands. "The wandering of her hands....as if she were receiving no information from the periphery, as if the control loops for tone and movement had catastrophically broken down." Amazingly, after about a year of therapy the patient learned to operate her bodily movements using an enhanced sense of vision.

My favorite of Dr. Sack's case studies in "The Man Who Mistook His Wife for a Hat" has been the role of the nervous system in body sense. After reading the chapters on phantom limbs I wondered if there is a neurological explanation for these behaviors. Are these losses random manifestations of the brain?

eglaser's picture

Where am I in all this?

Efferent copy and corollary discharge do explain more in depth how the brain functions. Patterns of activity, actions and reactions, movement, behavior, it's all starting to become clear. However there is still something I do not understand. I still don't get how all this adds up to me, to us, to a thinking, individual person. Where does intelligence fit in? Or personality? Where am I in my own brain? I simply still do not understand how the interactions of chemicals and charges gives me the ability to think of a post or appreciate poetry. 

I understand it but I don't get it. Seeing, thinking, it should make sense, but I still feel like we are missing large pieces of the puzzle. I look forward to seeing if these pieces are all filled in by the end of this class.

jlustick's picture

NS Organization and Hierarchy

My first question has to do with nervous system organization. We've talked about how the NS does not possess the sort of hierarchical system that we might imagine (no main director) but works by having a distributed system of closely associated parts that communicate equally with each other. In other words, neurons are grouped together in ways that allow for efficient means of communication. My question is, are these groupings constant throughout one's life or do they evolve over time? What is it that allows for the mind to develop? Is it the re-organization of neurons, the firing of new neurons, and/or the sequence of neuronal firing? Or something else entirely?

 My next question is how does this idea of coordination in the absence of a coordinator connect to human social habits and structure. Is it more "natural" for us to design a social system with a definite leader or not? How about our own desire to be leaders? Does the absence of a hierarchy within the brain somehow lead us to search for a hierarchy externally? Is our tendency to search for/create external hierarchy a downfall, a kind of unwillingness to realize that the most sophisticated systems (the brain, for example) do not operate in such a manner?

Bo-Rin Kim's picture

efferent copy and corollary discharge

At the beginning of this semester one of the questions I had regarding the brain was: how could an awareness of the self arise from chemicals and electric signals? I did not understand how psychological processes like consciousness and thought could arise from biological mechanisms. However, our discussion about efferent copies and corollary discharge has helped me to better understand this relationship between biology and psychology. It's fascinating that our brains are able to produce a copy of the efferent signals they send out and use this copy to determine if a signal is in reponse to an internal or external stimuli. And this ability to distinguish between self-produced signals and external signals is corollary discharge (I think..). This mechanism shows that these efferent signal copies help us to become aware of internal thoughts regarding self-awareness and how the self is separate from the external world. Moreover, efferent copies are used by our brains to predict the outcome or expected sensations of a given action that we engage in. This shows that these biological signals are also able trigger psychological processes such as the formulation of thoughts and expectations about the outcome of an action that the body engages in. Thus, while this mechanism does not directly answer how our brains produce internal thoughts, it shows that biology does play a big role in triggering and helping us become aware of these thoughts. And this gives us a greater understanding about how biology and psychology interact. 
BeccaB-C's picture

external signals, conscious awareness

It is also very interesting to look at the sorts of calculations that our brain makes through communication among neural regions, as these allow us to be aware of patterns and develop perceptions in relation to the input that our brains recieve. For instance, when we hear something, the vibrations of the sound enter our ear and vibrate in a location on the tonotopic map of our choclea. Our brain is able to register where the sound has come from, based on where it resonated in the chochlea, from which neural input signals were sent to the cortex. The power that the brain has to take information from sensory to cortical and present in the consciousness is incredible. In conjunction with this, as bkim stated, our brains' ability to make conscious deductions/reasoning from the physical efferent loops may give rise to cognition.
jrlewis's picture

I found out a little more

I found out a little more about Dramamine... It is a salt of the active ingredient in benadryl (diphenylhydramine) and a mild stimulant (closely related to one of the molecules in coffee, chocolate, and tea).  Diphenylhydramine is an antihistamine; specifically an H1 histamine receptor antagonist.  Common side effects are mild sedation and drowsiness.  It is effective in treating motion sickness related nausea because it blocks certain signals to the nervous system and/or encourages the patient to relax, close their eyes, and sleep.  This is how the brain would like to handle the discrepancy in information it is receiving anyway.

Dramamine is not as effective in treating chemotherapy-induced nausea; there are better anti-emedics, such as Zofran and Kytril.  These drugs are 5-HT3 receptor antagonists blocking serotonin receptors in the central nervous system and gastrointestinal tract.  Other important classes of antiemetics used for treatment of chemotherapy-induced nausea are dopamine antagonists and cannabinoids.  Chemotherapy is thought to cause nausea and vomiting by releasing serotonin, dopamine, and histamine or by damage to stomach cells which also results in a release of serotonin. 

It is interesting to think about why Dramamine is used for motion sickness, but not other types of nausea.  I suspect it relates to a more general trend in medicine.  When nothing else can be done to alleviate the specific discomfort, doctors sedate the patient so that they are less aware of their discomfort.  

Anonymous's picture

Dramamine and depression

I am 64 years old and have been having severe sleep problems for about 10 years. One of those problems is insomnia. So, I try alternating many different things to get myself to sleep. For the last 6 months or so, I've been taking Dramamine with 5HTP, and it worked better than Lunesta and other stuff I've tried. When I was about 10, I had chronic migraines and the doctor put me on Dramamine, once a day, for a year. It fixed the migraine problem. So I figured that there would be no problem taking it as a sleep aid.
Recently I've hit bottom. My negative thinking and depression has overwhelmed me. I was reading the book "Heal Your Brain, Heal Your LIfe" and had strong positives to every single indicator of Limbic system problems. So I did a search on Dramamine and the Limbic system, and found this forum. Although I found nothing that says that once a day Dramamine causes depression, there is an effect on the limbic system. My skin dryness has also increased and my feet have ezema so bad that they are cracking and painful to walk on. I stopped the Dramamine yesterday. No more of that. Being older, perhaps there is a greater effect on the limbic system. Maybe not. But I'm not taking any chances. My brain doesn't seem to be as resiliant as it once was!

Brie Stark's picture

We were discussing the

We were discussing the central process generators and I thought back to our Reeves discussion.  It is obvious that the central process generators of Reeve's extremities were not destroyed in any way, so I wonder if this lack of destruction of CPGs could lead to a more focused definition of what qualifies as paralysis.  Another interesting example I thought of was a friend of mine's sister -- at age 18, while diving, she broke her neck and became paralyzed from the neck down.  However, she began going to physical therapy (Operation Walk, Chicago) and learned how to walk again, despite not having any feeling in her legs.  She is also very mobile in her arms, despite having no feeling there.  Would this qualify as having damaged only her sensory neurons, while her motor neurons and CPGs remained intact?  This seems to justify another sort of definition/specification for paralysis (as doctors do still consider her to be a quadraplegic).

 I also have never thought of pain in the way of an 'out of the ordinary' response with which the brain does not know how to process.  In many ways, though, it makes sense.  On a personal level, I know that when I'm on an airplane in flight and I close my eyes, I get nauseated for a few seconds because my brain tells me that I'm flying a steady path but my perception feels a slight plummeting feeling. 

jrlewis's picture

After class, I was thinking

After class, I was thinking about the implications of the independent, but communicating boxes model of the nervous system.  In the absence of a director, how is a conflict between one or more boxes adjudicated?  Is one box right and the other merely wrong?  Could conflict be more than a prelude to violence or judgment?  Might the conflict between two boxes be a sort of opportunity.  A chance for creativity or making conflict generative.  At its best, the brain is skeptical; it suspends judgment in a conflict between two boxes.  The brain “listens” to the competing stories and combines the useful elements into a synthesis, a new story.