Neurobiology and Behavior, Week 3

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.

You're free to write about whatever came into your mind this week, but if you need something to get you started, what do you think of our evolving model of the nervous system, as an input output box consisting of input output boxes, capable of generating output without input and getting input from its own output (embedded in a loop)?

JJLopez's picture

Box within a box

This whole business about the brain is a box within a box within a box was interesting because I have never heard that idea before and also because it makes things more simpler to understand.  If I learn anything about how the brain works I know that each box (each part of the brain) generates outputs and inputs which in turn eventually create a functioning organism with a functioning brain.  I guess even though the idea appears very vague at first, you can ask yourself any question about human or animal behavior and you can answer it by saying well some part of the brain (box) generates an output (resulting in the behavior you are looking at) because: it received an input from something or it wanted but we don't know why.  I think this makes talking about the brain and how it works alot easier.  However, I wish that we can go more into details about each box and exactly how do they generate these inputs and outputs? Now that I know the basic outline of how brain parts function on their own and with each other, I think it would be a good place to start going more into specifics about these different inputs and outputs.

Hannah Silverblank's picture

Art as a Starting Point?

For this week, I took at look at Jonah Lehrer's book entitled Proust Was a Neuroscientist, which posits and explicates the notion that great neurobiological discoveries were already woven into the text and art of individuals like Gertrude Stein, Cezanne, Walt Whitman, and Proust. My attention was drawn to his book, which I had wanted to read for a while, as I stumbled across his Feb. 5th article entitled "Borges Was a Neuroscientist" in The Frontal Cortex. I find the general thesis very compelling - that poets and artists are practitioners of "loopy science" in making sets of observations, generating conclusions, and constructing experiments of mind, aesthetic, and text. Lehrer, on Whitman, writes about his investigative poetic and reflective strategies: "Whitman got this theory of bodily feelings from his investigations of himself. All Whitman wanted to do in Leaves of Grass was put 'a person, a human being (myself, in the later half of the Nineteenth Century, in America) freely, fully and truly on record.' And so the poet turned himself into an empiricist, a lyricist of his own experience. As Whitman wrote in the preface to Leaves of Grass, 'You shall stand by my side to look in the mirror with me.'" Whitman identified Professor Grobstein's theory that "brain = behavior" indirectly as he textually acknowledges the inextricability of body and mind, as "he was the first poet to write poems in which the flesh was not a stranger." Lehrer suggests that even the formalist stylings of Whitman's verse - his "unmetered form" - functions as a manifestation of his neurobiological findings and "the urges of his anatomy."

In the short article "Borges was a Neuroscientist," Lehrer reviews neuroscientist Rodrigo Quian Quiroga's new homage to Borges, which praises the writer's neurobiological intuition (excerpt below).

 

In the story of Funes, Borges described very precisely the problems of distorted memory capacities well before neuroscience caught up...In a study using electrodes to probe the hippocampus in epileptic patients for clinical reasons, we identified a type of neuron that fires in response to particular abstract concepts. For example, one neuron in a patient fired only in recognition of different pictures of the actress Jennifer Aniston; another responded only to images of another celebrity, Halle Berry. It is thus possible that these neurons link perception and memory by creating the abstract encoding we use to store memories -- especially considering that we tend to remember concepts and forget irrelevant details. If these neurons are lacking, the ability to generate abstractions may be limited, leading to pathologies such as autism or characters like Funes.

Even without this scientific knowledge, Borges's intuitive description is sharp: Funes, he wrote, was "virtually incapable of general, platonic ideas ... His own face in the mirror, his own hands, surprised him every time he saw them ... To think is to ignore (or forget) differences, to generalize, to abstract. In the teeming world of Ireneo Funes there was nothing but particulars."

 

If Borges and Proust have stamped out certain neurobiological processes of memory from their own observations and from their own human experiences, how should neuroscientists treat visual art, poetry, fiction? If many answers to biological questions have rested on the shelves of the library, what is the role of text in neurobiology? Should neuroscientists, in search of certain observations about the brain, turn to the literature that has already tackled the problem, and use art as a starting point?

Paul Grobstein's picture

art/literature/brain

How about not "answers to biological questions" but things useful in thinking about them can be found "on the shelves of the library" and the walls of art galleries?  Yep, I think that's so.  Certainly for neurobiology.  Cf Cezanne and Beyond ... and Back Again: Beyond Method/interpretation in Art/Science  and Realism to impressionism to abstraction and back again, in words.

skim's picture

Life must be more than just Input-Output alone

 

Last week's discussion introduced us to "Spaghetti Bowl Model" and prior to this class, I haven't ever thought of the nervous system as a network of input-output boxes. How much is being simplified in this network? By claiming that the brain consists of a box that receives stimuli and generates responses, what are we losing? What about that other "scientific stuff"?

In that sense, what even constitutes a stimulus? A biological/chemical internal change? An external change? Something physical, emotional, etc? What is mental stimulation? What happens when we learn? Is the acquisition of knowledge a stimulus?  Does that mean standardized testing/aptitude tests and writing papers are our generated responses?

For me, the issue here is the simplicity of the system.  I do see the convenience and value of such a system, but at the same time, I feel as though, it is too simple and that it undermines the complexity of what our brains can actually do – what we can do, as humans or organisms or whatever.  Life may be a series of stimuli and response, but I believe it has to coexist and blend into a cultural and social setting.

yml's picture

Boxes in boxes in ...

I'm glad and relieved to find that I'm not the only one who was little confused/skeptical and overwhelmed by the idea of outputs without inputs. Although, the examples were interesting and helpful, I was still skeptical to buy the ideas that the outputs from those examples were really without the inputs. Well, before anything, how do we define what’s input? Why isn’t the unconsciousness behavior an input?

I certainly appreciated how the nervous system was explained, in images of boxes. I liked that there weren’t many jargons and those million unfamiliar words to explain nervous system, especially that I’m not a neurobiology, or even a biology person. I think nervous system/brain is the one of the most difficult systems to understand in entire body. From my limited knowledge about the brain, we can’t really see and therefore have concrete evidence of how the brain works. We are making the best scientific guess based on many assumptions we create. Has anyone really seen “input” moving around, making its own way in the brain to cause “output”? Maybe we have? (and I just don’t have enough knowledge about this field) Well, anyway, this is why I like the idea of “getting it less wrong” to make “more right”. This is our best guess at this point, given all the information we can get. We are less wrong. But! We could get more right in the future! How open minded this is! I like it!

 

Congwen Wang's picture

What matters is the matter?

In our discussion on Thursday, what I found most interesting/confusing is the idea that our brains "generate output to get input". I have to say that the "flirting" really does not look like a good example for this notion: there has too be someone - or something - that makes us want to flirt with, and that is an input. I think breathing might be a better example for this statement. However, we might as well say, we breathe because our cells are alive - in a highly regulated microenvironment. From a material perspective, can we say that nervous system can generate output spontaneously under certain circumstances?

Of course, the techonology has not been developed enough for us to retain the bioactivity of a nervous system in vitro to directly observe this matter. But from what we know in the molecular biology, given the right chemicals, neurons can and will be activated by the electro-chemical gradient across the membrane. In this sense, there really isn't any output that is not generated by input - if we think that "certain circumstance" as an input.

 

 

rkirloskar's picture

Brain Studying the Brain

 

Meditation is all about gaining experiential wisdom. For example, we can study about what love is, why it happens but we really won’t know the complete truth unless we actually fall in love and experience it. So maybe our brain is after all, our passage to complete truth because we are able to study it and experience it at the same time.

 

Schmeltz's picture

Blaming the Brain

I have been thinking about the "it's all brain" argument and I am wondering how the legal system would be transformed if the majority of society accepted the Dickinsonian perspective.  If everything in life were a construction of our brains, then a sense of right versus wrong, the notion of justice and fairness, would merely be construed as constructions. Serial killers would be pardoned merely on the fact that their brains had constructed the crime.  They would not be sentenced to the death penalty or to life in prison because the defense would easily argue that it was because of their brains that they possessed no control over their actions.  Everything could be tried on the basis of insanity or a chemical imbalance or a result of some improper or just unusual or even usual proceedings of the brain.  The prosecution would have no right to say that their minds were polluted because the suspect would be presumed to have no mind, have no will power, have no control, and have only brain.  When considering the legal system and how it functions, it seems clear to me that the majority of society accepts the brain and mind model.  It is clear that the majority of society accepts the premise that we have brains, but that we also have minds that direct us to make crucial and significant decisions.  When you hear about serial killers, rapists, robbers, etc. you do not generally hear the media and society attributing this behavior to the brain, but to the person, the individual, the whole package.  You hear about how the person is sick, disgusting, disturbed, etc. Why do we rarely say that their brain must be sick?  There is something about these "criminals" that makes them different from the rest of the "normal" individuals whom adhere to societal laws.  If we were to say, yes, it is all brain, then can we really blame those people whose brains are steering them in the "wrong" direction?  I think there has to be something deeper - something not so physical and concrete that drives morality.  We cannot just offer people a cop out for crime.  Yeah, he shot that guy, but what can we do?  It was just his brain, just a series of inputs and outputs that drove that action?  How are we to control that?  I argue that it is not that simple and if it is, the majority of society does not agree that it is.  I think the majority of society thinks that there is a mind, that there is an element of control we have over ourselves, over our brain.  If we accepted that everything is a construction of the brain and that everyone is unique, with a unique brain, then how could we establish rules of right versus wrong and how could we ever come to any conclusions on morality and shared human values.  You think about how often people fail to live up to societal values and it is crazy to think that maybe it is really not them, and not their fault, but their brains' fault.  Can we blame the brain?   

AndyMittelman's picture

An Isolated Nervous System Does Generate Outputs

            Late in Thursday’s discussion we arrived at the conclusion that an isolated nervous system does indeed generate outputs. I have had somewhat of a hard time internalizing this notion that an isolated nervous system may operate independently of the normal inputs that we experience all day long. This conclusion has implications on end of life care for patients sustaining serious brain trauma, or patients in a “vegetative state.”

            This discussion begs the question, what does it mean to generate outputs? If we as humans generate outputs, does that mean we are living? Is the generation of output the key criteria for humanness? As humans, we internalize, process, react, and produce. But it appears that is not all that is involved. Previously I would suggest that someone in a “vegetative state” is not truly alive, in the human sense of the word. It seems possible that the nervous system may be “alive” independent of its normal surroundings, if it is independently generating outputs in an isolated environment. If it is possible for a nervous system to independently generate product regardless of external surroundings, is it possible to ever call someone dead? Purely because they fail to respond to any external stimulus, do we really have any way of knowing that they are not continuing to function independent of sensory input?

            Perhaps “being alive” is a human-defined condition wherein you input, process, and react according to your nervous system networking (recall the lines connecting the nodes). For example, if someone is defibrillated, (shocked, as in when their heart stops), and they respond to this stimulus by output (specifically returning to normal cardiac rhythm), then we call them alive. But if they fail to respond, we call them dead. It would appear that humans may have the ability to generate impulses internally, (as in the latest nervous system model we discussed), although they must have the ability to respond to inputs.

            Initially this seems satisfactory to me. But returning to the cricket model makes me challenge my proposition. If the cricket hears a song and doesn’t move, it’s because she has input the signal and the pathway has not led to the same output that it sometimes does. If she does nothing, isn’t that an output in itself? Doing nothing is a response. If we poke a corpse, is it possible that their nervous system is choosing a pathway of no response?

            So how is our “being alive” status tied to our nervous system? If a response is neither necessary nor sufficient to determine if we are indeed alive, how can we determine if we are alive? I have no idea on this one. Stepping outside of immediate selves, is it possible to determine if someone else is alive? If we cannot make judgments on the state of someone’s nervous system based on their ability to input, react, or output, can we truly ever determine if someone is alive? I have no answer to this question, but as we go forward with our exploration of the nervous system, I want to be able to define the limits of when a nervous system fails to operate and we could consider it "dead."

Colette's picture

  I found it quiet disturbing

 

I found it quiet disturbing that disciplines such as anthropology, psychology, etc., are forced to adopt the linear science model in order to gain legitimacy. Science is about making new discoveries, and learning new things. Its focus should not be about simply regurgitating facts. Sometimes times people appear to waste time trying to prove and re-prove things that are well established. We should want to search out what is new and unknown and strive for a better understanding of what we observe.

        Our model of the nervous system appears to have become more complete but it has a way to go. Our model can account for the basic underlying structure in that all creatures are able to get and receive inputs from outputs.  It does not do a very good job of accounting for marked differences between different organisms. The model needs to be able to explain what separates organisms from one another. What allows humans to communicate at a more advanced level then amphibians? We have the same underlying structures and we both receive inputs and outputs.  Is it more than the size of the brain?
 

natmackow's picture

Lots of questions

The notion of the brain as boxes inside of boxes inside of boxes ad infinitum as generators and transmitters of inputs and outputs is interesting. And to me, it makes sense. But I have to admit I was a bit dismayed when I first found out we wouldn’t be learning much neuroanatomy. I think it would be very interesting to learn about what these boxes are and which ones are generally believed to process and generate which outputs and inputs. How do these different compartments interact with one another?


    We did clarify, however, that we would be examining the building blocks of the brain, the neurons and I’m excited about this. The asymmetry of the neurons makes them clear input/output mechanisms, receiving inputs, transmitting them as outputs… But, as many of us are asking, where do the inputs and outputs come from? Are they generated by neurons? Is there an input/output creating mechanism in each “box”? What “creates” and transmits atypical messages, causing seizures, low production of serotonin, ADHD, etc.? We all have many questions about the information we were presented with last week and I think these questions will be more than sufficient to continue our exploration of the brain. Perhaps we don’t have to know what every little part of the brain is thought to do. Not yet anyway. For now I’m ready to just see where our questions take us.

 

cschoonover's picture

Nervous System

 After our discussion on Thursday, it was a little hard to accept the fact that there are some outputs that do not have an input in the nervous system. This may be due to my long-held view that for every output there must have been an input. It might be possible that breathing occurs without an input, but to me it seems as though the input is just not consciously recognized. And what about instincts? Is there some unconscious trigger? Or does it really happen on its own? In my psychology class we talked about some evolutionary support for instincts. So does that mean that evolution is the input? Despite my hesitancy to accept this model of the nervous system, I am trying to keep an open mind about this.

 

On a different note, I found it very fascinating that architecture is everything: that the way neurons, the same neurons in every animal, are connected accounts for the differences between a human and a frog brain. And that within the same species (i.e. humans) the connections vary enough that we are all different.

 

I also found an interesting podcast about learning and memory that was on NPR’s Science Friday last month.

http://public.npr.org/anon.nprmp3/npr/totn/2010/01/20100108_totn_05.mp3?sc=16&orgId=1&forsearch=0&topicId=1045&_kip_ipx=1512029001-1265590644

dvergara's picture

These boxes are giving me a headache

It might just be me, but even the question posted for the forum was overwhelming. Like most everyone else, I found the new input-output idea very interesting, but it simply overwhelms me at times. It reminds me of when I was young and would try to imagine the size of the universe, until eventually I would just imagine white space (because that's what you see after all the blackness and stars obviously) and have a big headache. Trying to analyze "inputs generating outputs, outputs generating inputs, and input output boxes inside other input output boxes" distracts me from the greater point; trying to understand how the brain and nervous system works. Even though this idea may be "less wrong" because it is a more accurate depiction of reality, is it really "less wrong" when the idea itself is confusing? I always thought scientific theory was supposed to make the universe look more simple [even though it is not]. Having said so, it's much easier for my brain to understand brains when simply imagining a loop with three components, input--brain--output; that way I imagine the brain as a computer/processing center of which input and outputs are dependent on to create more inputs and outputs. I know this model doesn't describe how the brain itself works, but the model given in class of millions of little boxes just didn't work for me.

emily's picture

Isolated Outputs?

 Our "loopy" model of the nervous system works for me! Last week, I was thinking about how the infinite combinations of chemical interactions in the brain allow us all to have personality and thoughts, to be different, and to be individual. This week, we discussed an evolving model of the nervous system opposed to an astimulus/response machine, which, because it is invariant would prohibit individuality. Our evolving model of the NS, with its numerous layers of "boxes" and countless neurons and neuronal connections, supports my previous thoughts about infinite possibilities for the brain.

My only question now is where do "outputs" from within the brain come from? Do impulses, such as desires and needs, other emotions, and thoughts, come from permanent evolutionary stores? If so, what triggers them to go off? Wouldn't environmental factors, which affect emotions and thoughts, act as stimuli to these outputs from within the brain, and thus be external inputs? Aren't all "outputs" caused by subconscious "inputs", like evolutionary instincts, chemical interactions in the brain requiring us to breath or causing us to become hungry?

emily's picture

  

  

kdilliplan's picture

The "Chicken or Egg" Question

 I had one big question during and after our discussion of the nervous system: which comes first, input or output? If we began with a model in which an input generates an output, obviously the input precedes the output, even if multiple inputs yield the same output or a single input gives rise to multiple outputs. Once you throw in the features that some inputs don’t result in any output or that some outputs happen spontaneously without any input, things get complicated. For instance, how do we know that the inputs that don’t generate outputs aren’t generating outputs we can’t/haven’t observe? How do we know that those “spontaneous outputs” aren’t the result of inputs we can’t/haven’t observed? While the model we talked about in class is “less wrong” than the ones we began class with, I’m not convinced it is accurate to include the idea of spontaneous output. There are so many factors that affect our nervous system that it seems unlikely that any behavior of the nervous system would happen without at least some sort of input. 

 The two examples of outputs for the sake of getting inputs that I can remember were flirting and breathing. I don’t think either of those could occur without some input first. People tend to flirt with someone they find attractive in some way, even if they don’t realize it consciously. Input: That person is attractive. Output: Flirt. The same thing is true of breathing. Even though we can breathe both voluntarily and involuntarily, the process is driven by a need to exchange gasses in the body. Input: I need oxygen. Output: Inhale. Input: I need to get rid of carbon dioxide. Output: Exhale. Both flirting and breathing can operate as part of feedback loops of the nervous system, but I remain unconvinced that the outputs can occur spontaneously. That is, I think that the loops ultimately begin with an input. I’m willing to believe that it is possible for some outputs of the nervous system to happen without input, but I will need to see some better examples.

 On a different note, I saw this video awhile ago and I thought of it during our discussion of the structure of the brain. It’s amazing what mice can teach us about our own brains! http://www.youtube.com/watch?v=Li5nMsXg1Lk

aeraeber's picture

Unopened Boxes and Life on Paper

For me, the most interesting part of the concept of the nervous system as “boxes within boxes” is the idea that some of those “boxes” cannot be opened. That is, some things in our brains happen without our realizing. We are not conscious of how our eyes work, or that our heart is beating, but it still happens. On another level entirely, we think things we don’t mean to, and react to events that happened last week or last year without them being brought back to our conscious mind for any discernable reason. The fact that the brain can trick itself and react to itself is a bizarre concept, one that I would love to explore further. How do we know what is going on in one part of our brain and not in another? Why can we control our breathing when we try, but at the same time don’t usually need to think of it at all? Why do we consciously react to some of the stimuli we receive and not others?

 

On another note entirely, it’s a comforting thought, that people who we remember are not exactly dead, but at the same time, not one that I’m just not sure I can accept. In my opinion, being alive involves having new thoughts, new ideas. Life is change, and a memory of a person, and any of their thoughts that they left behind cannot do that. Not being forgotten gives someone’s life meaning for those they leave behind, and is a part of that person, but not all of them. The greater part of them is lost to death. Oddly, this concept of the records and written thoughts that people leave behind being them is explored by a new science fiction TV show, Caprica, (http://en.wikipedia.org/wiki/Caprica_%28TV_series%29) so the idea seems to be on people’s minds outside our classroom.

MEL's picture

Evolving Model of the Nervous System

 

I found our conversation about the evolving model of the nervous system to be very interesting this week. Although I love simplicity and I believe these evolving models heighten our understanding of the nervous system, I feel it is impossible to make a correct model of the nervous system. We can’t restrict our nervous system to a model with inputs, boxes, arrows, and outputs. As we mentioned in class there are some outputs that have no external input. One topic we mentioned in class is the idea that the nervous system can create its own loop cycle of inputs and outputs. Like mcchen, I am also confused about what originally stimulated the nervous system to create an input. What caused the nervous system to originally create this input?   

 I also found our discussion about the neural similarities between invertebrates on the microscopic level very interesting. I was at first very surprised to hear that our neurons are very similar to the neurons of frogs and other invertebrates.  How can two organisms that act so differently have such a similarity? I think this further helps support the idea that even though our neurons are the same the way that they are put together is different.  

 

mcchen's picture

Nervous system model

 Our evolving model of the nervous system is definitely a start at understanding the complexity of the nervous system.  The idea that the nervous system is just boxes inside boxes inside other boxes seems like an attempt to compartmentalize the nervous system and to give it structure.  But in my mind, the nervous system can't be so restricted. I do not think everything that happens can just be put into another box because that makes it seem like there are definite boundaries to what the system can accomplish.  Could the nervous system itself produce its own input and then generate an output from that? I think my confusion is coming from where the "initial" stimulus of the nervous system is coming from.  If the stimulus was not from the environment then how does the brain decide to stimulate an output? Do desire/wants count as a stimulus ? Such as wanting to eat versus actually being hungry so needing to eat? And where does the control come from to ignore the stimuli from the nervous system? In people with eating disorders or any kind of deprivation activity, they are actively ignoring their bodies and the signals it sends. 

Riki's picture

no time for the gym

I read that the brain uses 70% of the body's glucose, which is one of the body's main source of chemical energy. This, to me, implies that interneurons are largely responsible for the brain:body ratio of glucose energy usage, which goes along with the boxes in boxes theory of the brain. This makes sense because the brain oversees the rest of the body. So I am wondering if someone who exercises their mind significantly more than another will "burn" significantly more glucose (can this be of interest to those looking to lose weight?), and if it's mental toil that does this, how much do mental struggles such as mood disorders influence the brain's glucose usage? What about intense dreams?

I googled "brain burn calories" and read this http://www.nytimes.com/2008/09/02/science/02qna.html . It seemed logical until I read this section:

"'There are good, sophisticated studies that show that concentrated mental activity, like doing a difficult multiplication problem in your head, increases the glucose uptake to the brain,' he [Dr. Levitsky] said. By how many calories? Less than, say, 20 calories of the 300, he estimated.
But you do not engage that long in such an activity, he said, so the difference might amount to only about 10 calories a day. That means thinking hard is not a good way to lose weight."
I don't know how much time he means by "that long", but I think that students, for example, probably do engage in difficult problem solving at least a few hours everyday when learning new concepts in class and working through homework problems or readings. So maybe students could lose weight this way.

lfrontino's picture

 If you think about the

 If you think about the opposite scenario, they fit in together pretty well. If someone is malnourished, it becomes almost impossible to focus on anything substantial such as schoolwork. We need proper nutrition in order for our brain to function, so the brain must burn up some of the calories we feed to it? 

mcchen's picture

This definitely confirms why

This definitely confirms why I am always hungry after only studying for a couple of hours!  I guess taking organic chemistry will do that to a person.  At least this means I'm not just completely "wasting" all the food I had only eaten a couple hours earlier only to need to eat again after studying. 

lfrontino's picture

Input/Output

 I think I'm still a bit skeptical about the idea that the brain can function as a series of outputs only, without the necessity of a certain input. Perhaps I've just had the idea that 'cause equals effect' engrained in my mind for so long that it's just difficult to sway me, but I still feel that there must be some input to trigger reactions in our body. 
In class we used the example of breathing as an output generated without an input. But wouldn't there have had to have been some type of input at some point? When a baby is first born and independent from its mother for the first time, wouldn't the lack of oxygen in its system be an input to cause the lungs to start working on their own for the first time? Isn't there some sort of reflux that causes these lungs to start breathing? I don't really know  a lot about biochemical pathways, but as far as menstruation, would there not be some sort of chemical trigger to the brain that causes this process to begin?                            From what little I've learned about the human body, I just find it impossible to think that anything can operate spontaneously, outside of the incredibly finely tuned machine that makes up our inner body mechanics. Does this just mean I"m not thinking about the brain in the correct way? Should I be more open to new possibilities? 

Saba Ashraf's picture

Nervous System/Brain Activity

        It was interesting to learn about the nervous system as a system of boxes.   I found the examples using crickets very helpful once it came time to relate them to the different possibilities the nervous system was capable of (such as taking in inputs with no outputs). Also, the fact that the frog brain was so similar to the human brain was amusing because when I think of a human brain, I would have never thought of comparing it to an amphibian’s brain. This does bring up the important point that the key difference between frogs and humans is how the building blocks are arranged in the brain, which is also something that was new to me. I had originally thought that the building blocks were significantly different from animal to animal, so the positioning of the building blocks wouldn’t matter much.   This makes me wonder how many more animals there are with brains that have similar building blocks to the human brain.

       Also, the point about an isolated nervous system having the capability of producing outputs was surprising to hear about in class. It is fascinating that even though we may not see a particular output, the nervous system is still able to generate it. This somehow reminded me of a recent finding that I read about in which brain activity was detected in some patients that are in a vegetative state. Despite the fact that they are unable to even blink their eyes, the patients’ brains were conscious. The technicians that took part in the research would instruct the patients clearly to “Imagine you are playing tennis” while they would scan their brains. For some patients, the brain scans showed nothing. However, for others, their brain scans would flash just as a normal and healthy human brain would as a response to the question. Basically, some patients in a vegetative state were found to respond with their thoughts and “living silently in their bodies.”

meroberts's picture

Harvard Law Implications on Input/Output boxes

Given the Harvard Law of Animal Behavior I think it's fitting that outputs are generated without a noticeable input/stimulus. If animals really do whatever they want regardless of controlled environments and precise manipulations, then it would make sense for their nervous systems to produce an output, or response, independent of a stimulus. It could be argued that self-stimulation exhibited by some autistic children is an example of the creation of output independent of input. On the other hand, it could be argued that the self-stimulation, or "stimming", is a product of a stressful environment, which would imply that stress is the input and whatever "stimming" behavior is the output.

I appreciate the evolution of our input-output box model, but I think there is still more to consider than just inputs and outputs. At the end of class, we discussed the concept of "architecture". The human brain is different from the brains of other animals because of the unique way the brain structures and lobes grow over each other. On an instinctive level, humans probably do not differ very much from other animals. However, humans have developed higher thought processes, including the ability to self-reflect and examine their own behavior. Is this evolutionary leap in intelligence a result of the structure of our brains? Or are the "boxes" inside the human nervous system different from the "boxes" in the brains of other animals?

molivares's picture

Creativity and connections

After Thursday’s discussion about the evolving model of the nervous system and the input/output loop, one of the points that really struck me was the idea that we all basically have the same “boxes” within “boxes” in our head, yet the creative differences between individuals is so vast.  It’s mind boggling to think that the connections between these boxes are what make our thought processes different.  On the larger scale, all of our varying thought processes contribute to a community of thinking that in essence creates a culture. I guess this all comes back to Emily Dickinson’s poem which illustrates how everything has come out of thought and the brain. Social constructs and social norms that seem to invisibly govern our life have arisen from our collective thoughts. But what I find interesting, is that so many of our grand explorations, discoveries, and works of art, things that have progressed human race, have come from creative people who have diverged from these norms of thought. Isn’t it crazy to think that everything that we have constructed in this world has come from the varying connections and circuits in our brain and nervous system?

sophie b.'s picture

I found our discussion on

I found our discussion on Thursday of behavior as a loop of inputs and outputs quite interesting. I haven't spent much time examining the roots of behavior prior to this course, so I've always sort of assumed that our behavior is a reaction to either external inputs or inputs from the nervous system. However, I suppose that it is very clear that the mind is not so simple- an article I came across researching for my web paper (http://www.nytimes.com/2008/09/16/health/views/16mind.html?_r=1&fta=y) reminded me of this discussion. The article discusses the way that depression is perceived- many believe that it is an over diagnosed condition and that often people who are diagnosed with depression are simply suffering from "normal sadness" as a reaction to traumatic or difficult life events.  However the author points out that external circumstances    can often effect the way that the brain functions: 

"Most of us can point to recent losses and disappointments in our lives, but it is not always clear that they are causally related to our becoming depressed. For example, a patient who had a stroke a month ago may appear tearful, lethargic and depressed. To critics, the so-called depression is just “normal sadness” in reaction to a terrible psychological blow. But strokes are also known to disrupt chemical pathways in the brain that directly affect mood." 

This sort of supports a more jumbled, loopy view of the way that external and internal stimuli can effect behavior, but at the same time is completely overwhelming, I suppose that while I know my previous perception of behavior is wrong, it's much easier to handle when one sees it as cut and dry. 

gloudon's picture

human brains

   So, this week we all saw the brain that Professor Grobstein took out of a lunch box, and carried around during class.  After hearing the story about how difficult it is to obtain a brain, I started to think why most scientists would want or need one.  In the case of our class, we got to look at the exterior of this brain.  We then learned that all of the convolutions on the exterior of the brain were not really the important "boxes" that we were interested in.  So, we didn't get to see the important "boxes."  Besides being cool, is there really any reason that our neurobiology class can learn from seeing a human brain?  

   If we tried to apply our evolving model of the nervous system to a real human brain (while whole), would we get anywhere?  To me, it seems that having a whole human brain doesn't correlate at all to our evolving model of the nervous system.  They seem completely separate, to the point where I am just imagining how the nervous system really operates out of the brain?  

   Perhaps part of the problem is that there are so many tiny connections, I can't make sense of the map.  To me, the heart makes sense because each major artery and vein has its own name.  The superior vena cava, or coronary artery is like Interstate 80 or 95 in that I can locate them.  Then there smaller back roads without names, and I can stand leaving them anonymous because I have a general idea of where the major connections are, and how they make the heart function.  But to me, the brain still seems like gook because there are no interstates for me to map.  Everything seems tiny and shuffled and scattered in the brain. 

lfrontino's picture

 I think everything seems

 I think everything seems scattered in the brain (and I have this feeling too) because we as students really don't have the opportunity to study it. I agree with you that looking at the brain as a whole doesn't help us get to the heart of the matter. If we got to look at dissected brains and really see the connections and the neurons, perhaps this would make it more clear? I just think because the brain is so absolutely complex, we are not often shown adequate models of it out of a textbook or on paper. It's difficult to visualize all of the amazing activity done by the brain without seeing it from all angles, both functioning inside a human and laid out on a table... Unfortunately, it's not the easiest thing in the world to study the brain this intently. 

Jeanette Bates's picture

My thoughts on the less wrong model

             The current model that we have for the brain is definitely ‘less wrong’ than our previous models. We can say with some certainty that there are some outputs that have no stimulus and some inputs that don’t give a response (e.g. when the female crickets don’t respond to the male’s song on some occasions).  The modern model reflects these ideas. The part of this that strikes me as strange is that it seemingly redefines the idea of thinking, and consequently, may redefine the idea of life. If a brain can give off electrical signals without any stimulus, it implies that it can think without any stimulus. We have also seen that if we place a brain (that is kept healthy) in a dish, or some sort of environment that is not attached to the life form that it came from, the brain still gives off electrical signals. Clearly this brain is no longer a part of anything, but yet it can still signal-it can still think. This means two things to me:

            First off all, it the brain can “think,” or at least give off activity in the absence of a body, then perhaps that means that it is the brain, and no other mechanism, that determines who we are. Granted, the body would be necessary for more complex forms of thinking that would, for example, involve inputs, but if it isn’t necessary for the most basic type of thinking, then that could mean that no soul or other external mechanism would be necessary either. This could be a big leap, but that is what it implies to me.

            Secondly, if the brain still has minimal activity without the body, at what point can we say that something is still living or has stopped living? Most people would probably say that a brain without a body-activity or no activity-isn’t really living. But what if that brain, at the same activity level, is inside a body? Does it really make that much of a difference? In a sense, the body is just another container. It is certainly more complex than a dish, but it is a container nevertheless. So if someone has minimal brain activity, or if he or she is in a vegetative state, is it fair to say that he or she is still living? This is an important ethical question, because if we say that that person is definitely alive, even if he or she needs artificial respiration, then it is our job to keep that person alive. But if we don't think that this amount of activity amounts to life, then it would be best to have that person “let go.” In other words, where do we draw the line? What should the definition of life be?

            So like all of the previous definitions of the brain, though this model is less wrong than all of the models that came before, it poses some new, difficult questions. What is thinking and what is life? Hopefully we will develop less confusing and less wrong answers in the future. 

aeraeber's picture

A life worth living?

I certainly agree that the definition of life is an interesting and difficult ethical question that becomes more complex as we learn more about the brain. I just wanted to add that, in my opinion, with people in a vegetative state, the question is not only whether they are still alive, but if it is possible for them to have a life that they would want to live. Many people hate the idea of living trapped inside their body, being able to think, but not to move or interact with others. I think allowing people to make their own decisions, beforehand, as in a living will, is a good idea.

mcurrie's picture

Questions and confustions

 Hello everyone so on Tuesday we talked about Emily Dickinson and how she is still alive due to her writing and our brain remembering her name. But what about all of those people we don't remember, whose names we have forgotten or do not know. Are they completely dead because we don't remember them or still alive in the sense that they are the unnamed people that we try to figure who they are. I don't know if I'm making any sense but i read this article about the youngest boy that died during WWII. That through records of his sister they figured his age and name and now fully know his story and contribution to WWII as a ships boy. Now knowing his name they were able to place a gravestone with his name so that his resting place is recognized throughout all of the many lost soldiers that some we still don't know who they are. And now that we have figured his name, where he rests, his story, has this boy come back from the "dead" or has he always been alive. 

Otherwise our other discussion about the nervous system was great. I enjoyed reviewing the nervous system and placing them all in boxes that are within boxes that are within boxes. Although of course like Lauren and probably others I'm am totally confused about outputs being created to get inputs. How do these outputs get started? Are they random or controlled or just a mixture of both? What usually occurs when outputs begin inputs or the general processes that these outputs are used for? Can't wait to find out more, hopefully answer some of these questions but i guess we'll see if there really is a less wrong answer.

Lauren McD's picture

nervous system

I'm glad that we started to discuss the nervous system in detail this week. The functions of the brain often trump the workings of the overall nervous system, but we have to remember that the nervous system is what connects our brain to our body. I appreciated the methods of interpreting the nervous system as boxes within boxes, interpreting inputs and outputs. Sometimes it is difficult to see the overall picture if we cloud our minds with extensive names and specific functions. However, I'm still interested in learning more about the specific biological aspects of the nervous system. The point in class that I found most interesting this week was that the nervous system can produce outputs without any inputs. This is difficult for me to understand because my education always focused on responses to stimuli. I think it's helpful to mention specific examples in order to fully understand the workings of the nervous system, which was done in class. I still don't think I fully understand outputs generating inputs, since the thought is so counterintuitive. Again, the examples are appreciated. I'm looking forward to learning more about the nervous system and how it enables us to function as human beings.