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An ongoing conversation on brain and behavior, associated with Biology 202, spring, 1998, at Bryn Mawr College. Student responses to weekly lecture/discussions and topics.


TOPIC 8

Since you last wrote, we're talked about lateral inhibition and color vision, with a focus on the creation of categories by the brain, about blindsight and the issue of whether one needs a "picture in the head" to "see", and about frog orienting behavior and "intrinsic variability". Which of these most affects how you think about the relation between brain and behavior, and why?


Name: Zermatt Scutt
Username: mscutt
Subject: Music and the Brain
Date: Sat Apr 4 15:46:35 EST 1998
Comments:
I really apologize for my deliquency about writing these past couple of weeks. I assure you that I've been thinking about what's going on and if it's ok I would like to make these essays up. So, I'll start with these two pieces.

I've been reading a couple of passages from the book, Music, the Brain, and Ecstasy. It's a really interesting book. Being a music lover and knowing the knowing the effect music can have on my moods, the author, Robert Jourdain, quickly got my attention. I participate in two choirs, the Bi-co Gospel Choir here and the Youth Gospel Choir at my Church. One of the directors once described singing as healing and becoming of angels. I love Jazz and instrumentals. I don't know how many of you listen to 106.1, there's this piece that they play, I don't know who it is by, but whenever I hear it I automatically stop in my tracks, I close my eyes and as it progresses, I get filled with this amazingly peaceful feeling. At church, we have these really talented musicians whose contribution to the worship has the effect of drawing you in. Last week, in one of my classes, my professor suddenly stopped in her tracks, she quickly recovered, explaining how she had been captured by the beautiful singing of some birds outside from the window. She had this look on her face and all of us were just simply amused.

I am sure you have your own experiences with music. So then it makes to wonder about the connection between music and our brain. How does music so charmingly captivate us and evoke such emotions. Read the book. But I'll share a little of the stuff I found really amazing. He tells about this lady Frances D. who suffers from Parkinson's disease. Parkinson desease is characterized by damage in 'two tiny bundles of neurons at the brain's core'. What results out of this is that the translation from intention in the brain to the actual action of the muscles sometimes fail. It's like the brain is still going through the process of delegating commands, but the body doesn't always follow its commands. It is typical for example for the lady, Frances D. to be walking and all of a sudden stop, unable to continue in her tracks. Jourdain explains how for Frances and many other sufferers like herself, music has this powerful healing effect. He describes, "One minute would see Miss D. compressed, clenched, and blocked, or jerking, ticcing, and jabbering-like a sort of human bomb; the next, with the sound of music from a wireless or a gramophone, the complete disappearance of all these obstrusive-explosive phenomena and their replacement by a blissful ease and flow of movement as Miss D., suddently freed of her automatisms, smilingly "conducted" the music, or rose and danced to it"(p301). He also describes a case where 'just the thought of music could do the job. He explains that, "One patient was able to 'play' whole compositions by Chopin in vivid mental imagery . The moment she began, her grossly abnormal EEG ( her 'brain waves') would abruptly turn normal as her Parkinson's symptoms vanished. Just as abruptly, every symptom would return the moment her clandestine concert drew to a close" (p301). Not only that, but success of the music depends on the taste of the person and their disposition at that particular time. How does one explain this phenomenon.

Jourdain explains this by describing the state of Parkinson's disease as a mismatch between what the brain anticipates to happen and what actually happens. This disharmony is what for example causes a patient to stop dead in their tracks right in the middle of an activity. Music apparently works for these patients because of its nature as a continuous, flowing entity that 'establishes flow in the brain'. This in effect helps the brain by 'bringing its anticipations into step'. I find this really fascinating, so I'll see if I can find more detailed explanations and understandings of how music works on Parkinson's disease.

Fascinating indeed. There are some descriptions in Oliver Sack's Anthropologist on Mars of similar effects of music in other situations, and there is an older symposium volume, Music and the Brain (Critchley, M. and Henson, R.A., eds., London: Heinemann, 1977) which you might want to look at. Can one explain the phenomena of powerful influences of music on behavior? Not at the moment, I don't think. But I think one can come up with several candidate mechanisms that would be testable. Want to take a crack at it. At least one might be related to Ruth Czarnecki's The Neural Score for Language and Related Action. PG


Name: Zermatt Scutt
Username: mscutt
Subject: Reality
Date: Sat Apr 4 15:52:46 EST 1998
Comments:
Appearance and Reality

I also recently finished reading this other book by Peter Kosso, entitled, Appearance and reality. So I found the ideas raised in class from tallking about the eyes and the information the brain gathers through them very interesting. Considering these ideas without a doubt sends one wondering about what one sees and the reality of things. About that same time we were discussing the act of seeing in this class, we were struggling over the ideas of Realism and Constructionism in my phylosophy class, trying to see if these two philosophies could be reconciled. In a general sense, Realism can be described as the view that there exist a reality independent of our conceptions or perceptions of it. Constructionism for its part argues that there is no reality independent of our interpretations and conceptualizations. As far as the constructionist sees things, none of us can talk of a 'reality that is' because of our inability to escape our conceptualized practices. At first, I vehemently argued against the constructionist view. What do you mean there is no 'reality' that we can speak of.

I then wrote my paper for that class where I argued against the constructionist, Thomas Khunn's thesis in The Structures of Scientific Revolutions. I cornered my argument on the fact that Kuhnn's writing in numerous instances could not even refrain from positing a 'reality that is'. His constructionist ideas were unquestionably founded on this reality that even he could not keep quiet about. Although Khunn didn't convince me of constructionism, he sharpened my understanding of the dillemma between the two philosophies. It is undeniable true that our perception of the world is conceptualized and theory laden. Realism has a very hard time going around that challenge. I still vehemently resisted the constructionist view, but I then started taking its claim more seriously and the challenged it presensented to the stout realist. Kosso's work then came in the picture. Kosso, describing himself as a 'realistic realist' sought to address these issues by using Physics to argue his Realistic Realism philosophy. He builds his case using the Theory of Relativity and Quantum Mechanics. Read the book, its very thin and very interesting. In light of his ideas and the discussion in class, I came to the realization that realism could not stand on its owm as much as constructionism could not stand on its own. These two philososphies need each other. The constructionist is right that the realist is constrained by her conceptual frames. But at the same time, our conceptual frames can't help being constrained by the reality that is.

Why am telling you all this. Well, just wanted to share my frame of mind in thinking about the issues of what we really see.

No apologies needed. I'm glad our course material intersects well with other things you're thinking about. And they are indeed both closely related and worth thinking about. Clearly the brain is "constructing". But its constructions are constrained by information it gets from sensory input pathways. That matches your argument fairly well, no? And perhaps gives us a basis for suspecting, if not proving, that there is an external reality? PG


Name: RIT
Username: rtrimiew@brynmawr.edu
Subject: In Living Color
Date: Mon Apr 6 02:02:15 EDT 1998
Comments:
One of the demonstrations used illustrate that we do not see color, was the scotopic light experiment. In which the rods detected light at very low levels, still saw the wavelengths but saw no color. I was reminded of a book I read (for lib. studies) in which a man after suffering a head injury, could only see black and white. My question is, why would the part of the brain that puts the color in what you see, take the information from the rods to put in what you are seeing? If in order to see color, WE require a combination of signals, why would we expect our brains to see color without the combination? I agree that color is all in our minds, but that does not mean that it does not exist. We simply cannot say one way or the other. We do know that there are different wavelengths. They could correspond to the color spectrum. Because our minds are not arranged to see color through our rods, that does not mean that it does not exist.

That we don't see color based on signals from rods alone says that the experience of color is not inevitable but doesn't, I agree, say that "color does not exist". What the latter is intended to stand for is the idea that there is no fixed correspondence between wavelength and perceived color, that a given color percept may be caused by a particular wavelength of light but can be identically caused by any of a variety of mixes of wavelengths lacking that particular wavelength. Its THAT observation which says that "color" is a brain category, rather than an external reality category. That ok? PG


Name: Christy Taylor
Username: ctaylor@brynmawr.edu
Subject: Plasticity of the tectum
Date: Fri Apr 10 10:40:26 EDT 1998
Comments:
Well, I am definitely going to diverge from the assigned topic today because I got excited about a concept that we talked about on Tuesday's class and how it related to the web paper that I just turned in.

My most recent web paper was on phantom limbs. A particularly interesting topic regarding phantom limbs is the plasticity of the cortex. Plasticity basically means that when the neurons in the brain are no longer receiving stimulation - as occurs after amputation for example, the neurons will re-organize so that inputs from other areas that are still attached send input to the reorganized neurons. Therefore, when these neurons are stimulated by this sensory input, the person "feels" sensations in areas that are no longer attached to the body.

I was thinking that since the tectum in the eye has a similar role as the cortex in the brain, and therefore receives input from certain areas in the retina, just as the cortex receives input from certain areas in the body, that when damage occurs to the retina, the tectum may re-organize - just as the cortex reorganizes in the brain.

What would happen if this indeed did occur? Well, I can only predict that "phantom sight" or "phantom vision" would commence. Now, I am not sure if this really has been known to happen, but I don't think I would be all tha surprised if it did because inputs from the retina would be sent to a re-organized tectum, that would stimulate areas on the retina that had previously been damaged or destroyed, so sensations of vision would occur. It makes me wonder whether people that become blind later in life have phantom visions and what exactly they "see?"

Do they feel pain in their eyes because their corollary discharge signals are not in sync with their sensory input? This is what occurs in amputees that have phantom pain. . . It would be an interesting topic to explore further.

Interesting, and appropriate set of thoughts, though I'm having a little trouble following you through which areas might reconnect to what, and what the consequences might be. In fact, in some experimental situations it is known that surviving retinal regions DO occupy tectal areas normally occupied by damaged retinal regions. And the upshot might well be that lights at some location (activating surviving retinal regions) might be mislocalized to other places (those which would normally activate the lost retinal regions). I see you suggestion that complete loss of retina might lead to activation by some other inputs, and hence to "phantom visions", but am not sure where you expect your corollary discharge signals to come from. Definitely worth thinking more about. Thanks. PG


Name: Meredith Ralston
Username: mralston@brynmawr.edu
Subject: picture
Date: Sat Apr 11 19:38:03 EDT 1998
Comments:
Most fascinating to me is the interaction between the picture in the head and what the eyes take in. Though blind people have no picture in their heads coming from the retina, is there anything that they're still seeing, based on the individual case?

It makes the picture we see seem much more three dimensional, not only in how it appears, but also in the fact that different pieces of it are coming from different parts of the brain.

I am especially curious about what the world would look like to someone unable to see motion, who sees in still frames...How does this function and why does it happen?

Intrinsic variability is interesting too, but not as gripping. I accept it as a fact of daily life, whereas considering how I see what my eyes are seeing is stranger. A neurobiologists view on behavior would be interesting to compare to that of, say, an anthropologist or psychologist. Because in the case of a human, we can begin to consider societal influence in behavior. It seems as though that ought to get tricky.

What do we need a psychologist or an anthropologist for? After all, social influences are just action potentials in sensory neurons, no? Yes, of course, a psychologist and an anthropologist would shed extra light on seeing (but why?, those influences really are just what I said above, no?). And, maybe, also on "intrinsic variability", which we have a little more to say about which might make it more interesting. In fact, "intrinsic variability" is probably a part of seeing. PG


Name: Elaine de Castro
Username: edecastr@brynmawr.edu
Subject: Instinct
Date: Sun Apr 12 18:03:05 EDT 1998
Comments:
Blindsight made me think - what does "instinct" really mean? What are we saying when we say we're going with our intuition or gut feeling? Some people have hypothesized that ESP and deja vu are actually a result of our unconscious not informing our conscious of certain events. Though I find it a little difficult to physically be in a situation or location and not have a conscious perception of it.

And also, just when I was thinking, "Maybe at the end of the semester, Dr. Grobstein is going to say, "Ha! There is no I-function!"", I guess there is. Should the definition of I-function be more finely tuned? In the case of the pleurobranchus, if the I-function is related to "choice", I am tempted to say there may very well be no such thing. Is conscious thought a factor in choice? But in terms of blindsight and being consciously aware, and paraplegics, well, ok, there is an I-function. Very confusing. Maybe I'm not thinking hard enough.

One more thought - completely random - what is it about stereoscopic pictures that makes 3-D illusions visible to those of us who have "normal" vision? I can't seem to tell a shading or color difference on the parts that are supposed to "stick out" - what's up?

I'm not sure, but either there are cues parts of your brain doesn't pick up (as mine doesn't) or parts of your brain are less good at persuading other parts they should be listened to. And I think you're thinking plenty hard enough. No, I'm not going to say "surprise, no I-function". As you say, we've got too many observations to sweep the thing under the rug at this point. Yes, we'll talk a bit about intuitions and gut feelings, and what might be the difference between conscious choice and what Pleurobranchea does. PG


Name: Julia Johnson
Username: jfjohnso
Subject: Grrrrr.....
Date: Sun Apr 12 18:05:25 EDT 1998
Comments:
The first question was, "Does everyone understand how color is another creation of categories by the brain, that color is really a construction of the brain?" (or something along those lines) I just nodded right along. The second question was, "Is everyone comfortable with this?" I doubt that I was the only one shaking my head. No, I am not comfortable with the idea that color is not an intrinsic property of different materials, a physical characteristic of different wavelengths of light, etc. No, I am not comfortable with the idea that my brain is smarter than I am and needs to cover for my inadequacies that "I" don't even know about. No, I am not comfortable with the fact that sweet Miss Johnson (my teacher had my same last name. It happens a lot with the Johnsons, Smiths and Browns) was a duplicitous liar when she taught me that the sky is always blue and that when we look up, we all see the same thing. Perhaps I am being rash...but it was somewhat unnerving.

I think that what unsettles me so is the simple realization (that has happened before and will probably happen many times) that we can function pretty well from day to day without knowing or needing to know that we are constructing inside of us so much of what is going on around us. We compensate for blindspots and we compensate for differences in lateral inhibition daily. We incorporate these processes and categories into our routine without even understanding that we are doing it. The implications here (that we understand so little about ourselves and our own processes) are going to take some getting used to. No, I am not comfortable with it, but I am processing it. Knowing how much of what we see in our head is not a true replica of what we are taking in with our eyes is pretty overwhelming. It is, at least, for those of us who have taken it for granted all these years that "what you see is what you get." Not so, Miss Johnson.

Now THAT's what I wanted someone to say. Thanks. To you, and Miss Johnson (the other), for being a foil. Yes, "without even understanding that we are doing it". Until now, of course. Which is a good general principle: we can all learn, and should. Constantly. Not only about what is going on out there but about how we're making sense of what is going on out there. And remember, its not all "compensating" for our failings. There's some clever stuff too that we know how to do without knowing that we know it. Indeed we may know more that we don't know about than that we do know about. That any more appealing? PG


Name: Rani
Username: rshanka1
Subject:
Date: Mon Apr 13 15:07:25 EDT 1998
Comments:
Out of all the things we have discussed relating to the visual system, what strikes me the most is the diverse variability in vision among different species. I had never stopped to wonder why all the sweet, grazing animals had eyes on the side of their head and how all the carnnivorous animals have eyes positioned toward the front to enable partial decussation. Itís interesting to think about the development of the visual system evolutionarily - as it became more complicated over time, partial decussation evolved, the projections from the retina to the optic tectum becomes more detailed, the neuronal patterns and their connections become more tightly connected, and thus the picture- that we see as an image becomes more and more complex. The sharpness of vision is, though no indication of how advanced a certain organism is, an adaptation to its environment. When thinking about humans, then, why is there such a variability in vision- how is it that so many humans need glasses, supplemental lenses? Is it an obsession with being perfect?- does it have to do with environment and/or genes? Is there any truth to the stereotype that people with glasses are smarter?....hee hee.

I didn't used to think so, but since getting glasses .... Interestingly, correcting vision with glasses has less to do with the nervous system and more to do with the optics and size/shape of the eye. What glasses do is primarily to sharpen the image on the photoreceptors, before it gets turned into neural signals. And yes, indeed, the evolution of the visual system is a very interesting subject. What makes you think partial decussation would occur later in evolution than complete decussation? And I wonder if its true? PG


Name: Pernar
Username: lpernar
Subject: brain+behavior
Date: Mon Apr 13 15:11:24 EDT 1998
Comments:
I think that each point addressed in lecture offers a way to look at the entwined nature of brain and behavior. I felt as though the phenomenin of blind sight and the irrelevance of a picture in the head makes the most compelling point about the brain and behavior.

Considering the man who could not report seeing a light flashed at specific points in his visual field, but could point quite accurately at this light, a point comes up aboutthe relationship of the brain to behavior and vica versa that was not necessarily too lucid before.

As we discussed the recurrent collaterals and the fact that outputs change inputs and thus may change outputs again, the evidence of blind sigt had not been presented. The evidence from blindsight points out the fact that ouput may be rendered without input ebing detected by the i-function, and output also doe snot have to alter input. Afterall, the person pointing at the light he does not see is not going to change his position to the light to see it better, or such. About the first point, it seems as though blindsight makes the pointing response almoist into a 'reflex'. When the knee jerk was discussed, the dissociation between the leg movement and the I-function was repeatedly stressed. This dissocoation was also used to define the reflex terminology.

Another thing that ties in with the dissociation of the I-function and behavior, but ties together brain and behavior is the frog movement in the frog who leaps forward even though the prey is to it side. The frog may perceive it there, but the brain does not allow for a proper information conveyance. Hence, the frog does not act on what he sees. Again, pointing out the importance of the role of the brain in behavior.

A number of interesting points, with linkages between them that I'm pretty sure are clear in your mind but may be less so to a reader (this one, for example). In what sense, for example, does a frog "not act on what he sees"? What are you imagining to be the frog, as opposed to the actor? as opposed to the seer? In what sense does the "dissociation" "define the reflex terminology"? I like your attention to a "dissociation" between the nervous system acting and the "I-function" (a restricted part of the nervous system) acting, but am less clear about why the blindsight makes the point more "lucid". PG


Name: Rachel Mosher
Username: rmosher@haverford.edu
Subject: re: Music and the Brain
Date: Mon Apr 13 17:31:10 EDT 1998
Comments:
I found the comment about music and its relation to Parkinson's Disease intereseting because I am currently trying to relate music to the brain for a paper in another class. I have heard that music is supposed to balance you mentally, providing some sort of escape for your brain from the normal activites and also providing the brain with an outlet for emotions. I have also heard about the reports which claim that listening to classical music enhances intellectual capabilities. It seems strange to me how music could do all of these things but at the same time quite possible. There is probably an area of your brain specifically used when listening for music. When activity happens in this area, the rest of the brain is perhaps ab lit less cluttered or calmed or something.

It is interesting that the fluid and predictable nature of music is what is helpful for relieving the symptoms of Parkinson's disease. My question is, is music inherently predictable? How does the brain actually know what is going to come next in music? It is experience based on listening to a lot of music and knowing what usually comes next or is there some physical aspect to the music that makes the sound waves come in in predicatable frequencies?

One other question is what about music that has a lot of random breaks in it and is totally unharmonic? It seems like a lot of the 20th Century music is more abstract in nature and is not meant to have basic predicatbility in tune. Does this mean that when a Parkinson's Patient listens to this type of music the symptoms do not go away? Or is it any type of music that relieves the symptoms? I should probably read the book . . .

And/or some other ones (see my response to Zermatt's thoughts on music above. Yes, both physical and physiological variables influence how one hears and how predictable it is (see, for example Demonstrations in auditory perception). I like your question about whether what is at issue is music per se, or particular types of music. And, in particular, I'm intrigued by the issue of whether "predictability" makes a difference. My guess is that it does, but there are various kinds of "predictability" in music, no? In my experience, at least, some music is more or less immediately predictable - a sequence of tones makes the next tone predictable - whereas for other kinds of music (including more "modern" music?) one waits longer for the "prediction" to come true? Certainly worth exploring further. PG


Name: Ruchi
Username: rrohatgi
Subject: seeing??
Date: Mon Apr 13 19:09:13 EDT 1998
Comments:
After talking about how one does not need a picture in her head to see, it made me think more about this and how these two types of "seeings" affected behavior. As I understand, the picture in ones head is a mental image that allows one to analyze and to create and imagine. I understand how the picture in ones head differs from the one that one just "sees" and I understand the importance of the picture in one's head. However, I am wondering if the picture in one's head when one is "picturing" or thinking about a person or place with closed eyes is really seeing? Is that the same picture in one's head that we were discussing? I was also thinking about another point that professor Grobstein had mentioned-how you could stop at a stop sign without a picture in your head...how long would you have to "see" something for it to become a picture in your head? Would you just have to think about it for a while? When does seeing something become a picture in your head, or can some things that one sees never become pictures in heads since there are a lack of certain connections between I functions and the NS? Maybe I'm confusing some issues here. Basically, you can "see" things without a picture in your head and you can have a picture in your head without being able to see it, and the difference between these is the "you"- the I function or the rest of the NS...

No, I don't think you're confusing anything. The basics are, I think, as you describe them. And from them follow exactly the sort of next questions you're asking. Which are being asked to varying degrees in ongoing research in both neuroscience and cognitive science, without yet having clear answers so you might well want to join in. Yes, there is some evidence for at least some neural similarities between the picture in your head when seeing and the picture in your head with eyes closed. But there are almost certainly differences as well. As for how long it takes to "get" a picture? That seems to depend a lot on what it is and what the context is. PG


Name: Libby O'Hare
Username: eohare@brynmawr.edu
Subject:
Date: Mon Apr 13 20:46:08 EDT 1998
Comments:
This week, I would like to write about an experience I had last weekend. I would have writen it in last week's fourum, but we didn't have a fourum...

Last weekend, I was at a the Seven Sisters Tennis Championships at Wellesley College. My partner and I were in the second flight for the doubles draw. The weather is noyousishley bad for 7 sisters tournaments, and this year was no different. Rain on Saturday and snow on Sunday sent all five teams indoors to Wellesley's beautiful facility. Unfortunately, the indoor courts were extremely fast. So fast, in fact that a good serve was almost always unreturnable. Anyway, I was noticing that when I was in the position to return serve, often my racquet would be back, and my body turned as a bad serve landed in the net. In other words, my preparation was so fast, that I had already tracked the flight of the ball as being either on my forehand or backhand side and was turning in response to this by the time the ball had only traveled 25 feet in the air. Now, this is not an unremarkable thing among tennis players. All the other players there experienced the same thing. The remarkable thing is the speed of the human nervous system. Our discussions of visual input and 3-D transformation in class seemed to leave out something. These discussions seemed to account for only one link of the visual chain at a time. In fact, our visual system is increadibly complex. Returning a serve in a tennis match involves a series of events and decisions that occur in rapid sucession. First I have to track the ball from my opponents hand as it flies through space, next I have to decide which shot I want to hit (taking into consideration the speed of the ball etc.), then I must have perfect timing to hit the ball with exactly the right angle and direction.
Hi I'm back.. I accidently hit the post button instead of review for posting...

I wanted to share my experience because I think it illustrates the bigger picture in understanding behavior.

Glad you did. And actually bears on two things. One is the speed of the whole process, as you emphasize. The other is you "noticing" that you had ... . I meant to point this out in class yesterday, when we were talking about whether there were some positive features to not using the "I-function". Most athletes know that for rapid, skilled movements its better if they don't "think about it" and instead "let their body do them". Which is to say, they're better (certainly more quickly) done without the I-function. PG


Name: Rachel Kaplan
Username: rkaplan@haverford.edu
Subject: Undiscovered Country
Date: Mon Apr 13 21:02:07 EDT 1998
Comments:
I am intrigued by "intrinsic variability" because the concept is counterintuitive to me, as far as it is referring to unpredictability. It is easier for me to put my faith in a model of patterns rather than in one of randomness. After all, even in chaos there is order. I believe that we simply have not discovered everything there is to know about neurons. Once technology advances to a high enough level, everything will be explained. At least this is a possibility that we have to consider. It is too easy to say that things happen "just because" or due to an act of God. These explanations are not good enough. P. Grobstein has written in "Variability in Brain Function and Behavior" (URL: http://serendipstudio.org/bb/EncyHumBehav.html) that "...within neurobiology it raises no eyebrows whatsoever to assert that the outputs of a given neuron reflect not only its inputs but also variations in signal processing characteristics which occur for reasons largely or entirely intrinsic to the neuron." Can we not hope at some point to be able to predict variations in signal processing characteristics for individual neurons?? I'm sure we can discover the "methods in it"; the key is to figure out how to control for the zillions of variables. Even the slightest difference in ion flow may affect the output. Perhaps the system really is too complex for us ever to discover all the reasons; however, I assert that they are there to be found.

Its a very interesting and very germane issue. Is there "real" unpredictability (in neurons or elsewhere) or is it simply the case that there are too many variables for us to keep track of? In one sense, it doesn't make any difference: things can be equally mysterious either because we don't know know all the variables and their interactions. In another sense, though, it makes a lot of difference: if there is no "in principle" unpredictability, then every organism's behavior (including our own) is "in principle" predictable, which raises some difficult issues with regard to personal choice and free will. From this perspective, its nice that, as we discussed briefly after class, scientists are increasingly coming to understand that in nature, unlike in the brain, it is randomness and not patterns that come first: things behaving unpredictably is the norm and it is patterns that need to be explained, rather than patterns being the norm with unpredictability needing to be explained. A physicist, Erwin Schrodinger, is the first I know to make this point explicitly, in a wonderful little book called What is Life?. And there are a number of exhibits on Serendip that relate to order from randomness if you'd like to start exploring the matter further. PG


Name: ingrid katz
Username: ikatz
Subject: referring to Julia...
Date: Mon Apr 13 21:50:09 EDT 1998
Comments:
I am going to refer back this week since I liked Julia Johnson's comments and have always liked them and meant to comment on them and end up getting carried away on another topic...so julia...this one goes out to you and Miss Johnson.

The question on the table is what exactly is the "I" seeing and can we say that perhaps the brain is "smarter" than we are, by integrating images where there are none and convincing us of color that may or may not be universal? I agree, Ms. Johnson (Julia, that is) that this is indeed a very disconcerting thought - one in which the term "blue" is not necessarily an objective thing... Still, we are taught in Physics about waves and optics and certainly about wavelengths belonging to specific colors in a spectrum. So, how can it be that such a clearly conrete thing (with numbers and greek letters letting us know it) is really potentially "all in our mind"?

If, in fact, we can distinguish what the "self" perceives as color from what the "brain" perceivevs as color, then the whole notion of the brain dictating behavior may be less real than previously envisioned. Indeed, one can consider that behavior is purely adaptive to the restraints that a functioning society puts on us..not what our brain would have us perceive. Perhaps our brain sees "magenta" when everyone else is telling us "go - the light is green". So, we adapt and assume the light is green, behaving as if the color discrepancy never existed.

Perhaps we are more in control of our functioning capabilities than necessarily evidenced by such an example, but it is important to consider the potential chasm between brain and behavior when examing such notions as the blindspot or color perception. In the end, the quesiotn still remains, "where is the self?" As Miss Johnson said, "what YOU see is what you get." I am left pondering "Who is the 'YOU' who is getting it?"

Here's again to Miss Johnson (both of them). Can we be sure we have a few points straight? The physicists are "right" about wavelengths, and the relation between wavelength and perceived color, so long as one deals with only a single wavelength at a time. In general, most people perceive a particular wavelength as more or less the same "color". What divorces color from physical "reality" is that exactly the same percept can be achieved by a large number of different mixes of other wavelengths. In this sense, "yellow" is not an aspect of physical reality but rather a category corresponding to a particular pattern of activity in photoreceptors, a category created by the brain.

Now, where is your "whole notion of the brain dictating behavior may be less real than previously envisioned" and "the potential chasm between brain and behavior" coming from? Indeed, the brain is probably "smarter than we are", certainly in the sense that it gives us to perceive something as universal which in fact probably isn't. Remember, though, that (at least insofar as one accepts the brain=behavior idea), the "we" is actually a part of the brain, one which may not know at any given time what the rest of the brain is doing but can in fact find out about it (as we have been doing in class). So maybe its actually "smarter" than the rest of the brain? Yes, we do need to talk more about the "I-function" and its relation to a sense of self. And we will. PG


Name: Anne Frederickson
Username: afreder@haverford.edu
Subject: The image in your mind
Date: Mon Apr 13 22:04:02 EDT 1998
Comments:
I find it really interesting, as everyone else does, that the image that we think we see is not what our eyes are really sensing. And while the mechanisms behind how the brain fills in the information are really interesting, I have to say that I find the idea of the image in our minds to be the most interesting part of vision. Even though we have been able to show that you don't need an image in your mind to behave in response to the visual stimulation, it is the image in the mind that produces, in my view, the most interesting behaviors. These are the behaviors that we think about, usually, before we act on them and in doing so, we form images in our mind. How is it that something that we may not have seen in a while can be so clear in our minds? For instance, I can practically see home when I think about my mother. It is not a fuzzy image, and it doesn't seem like it is from any particular instance that I am getting my image. An even better example is a time when I only saw something for a minute and now, years later, I can recall every visual aspect of it very clearly. I am also fascinated by the ability of the mind to invent images. You can imagine a scene that you have never seen. How is that? If the image in our mind is based on some representation of reality, then how can we construct images that are not based on reality at all.

I know that this is more memory based but I am continually fascinated by the brain's ability to create sensory experiences out of nothing.

We've yet to talk about where visual images come from if not from the eye and optic nerve, and will. In the meanwhile, though, we've laid some useful groundwork, no? A picture in the head is a pattern of activity across various areas of the brain ... so how other than by stimulation of photoreceptors might a pattern of activity arise? PG


Name: Akino Irene Yamashita
Username: ayamashi@brynmawr.edu
Subject: Perceptions
Date: Mon Apr 13 22:04:56 EDT 1998
Comments:
The comment that struck me the most during last week's lectures was when Professor Grobstein said that a "color-blind" person who is missing a retinal photopigment has a totally different picture in his/her head than a "normal" person. Also it seemed that this way of seeing would be so different from "normal" people that a color-blind person could never really explain or convey this picture to a "normal" person. So when he said that some people also have extra photopigments, it seemed that they would also have a completely different picture! The difference would be that unlike "colorblind" people they can function normally in society (though I guess colorblindedness wouldn't be that much of a handicap compared to others).

Then I thought, aren't the ratios of photopigments in our eyes probably slightly different for each person? So maybe there are no two people with exactly the same way of seeing? Maybe what I think of as "blue" is not what others think of as "blue"? It seems there is no way to test this! Also, since I am very nearsighted and have a lot of astigmatism maybe the picture in my head with my glasses off is also something completely different that I can't really convey to other people? Would this be true for other senses as well?

On Libby's post on tennis, I read somewhere that there are many different types of "intelligence" and that athletes have a special kind of intelligence (I forgot the exact term they used) related to their ability to process visual and other inputs and coordinate them with resulting motor outputs. The brain must be making a number of very complicated calculations to say, know where a ball is and when exactly and in what direction a racket or bat should be swung to hit it. Just because the "I-function" isn't consciously making quantitative calculations like in math class doesn't mean other parts of the brain aren't.

The "blindsight" tests seeming to indicate that the brain is processing visual inputs without them being perceived in the conscious "I-function" reminded me of my "subliminal perception" paper. In it I described some experiments in which subjects reported not observing a visual input but produced outputs relating to it anyway. In the simplest of these experiments (conducted in the 19th century) a flash card with a character printed on it was shown to the subject at a far enough distance away that the subject self-reported not being able to identify the character. However when the subject was forced to guess what the character was the accuracy rate was higher than mere change would predict!

It is very interesting (though a bit scary) how it is hard to be sure whether the picture in our heads actually corresponds with reality.

Does it get any less scarey if one begins with the proposition that "reality" is actually a construction of the brain? In that case, at least, one doesn't have to worry about "whether the picture in our heads actually corresponds with reality". One can, instead, focus on the extent to which the "picture in our heads" helps us in getting food, avoiding stubbing our toes, and so forth. And that it demonstrably does, pretty well, no? Yes, the picture may be (probably is) somewhat different in different people, but its also modifiable, in part by interacting with different people, so maybe the differences are actually an advantage, rather than a disadvantage, since they suggest ways the picture in any given person's head might usefully be modified? PG


Name: Bonnie Kimmel
Username: bkimmel@brynmawr.edu
Subject: thoughts
Date: Mon Apr 13 22:58:05 EDT 1998
Comments:
I've also been thinking a lot about the larger implications of the fact that the brain adds a lot of information/combines signals/creates categories so that we see what we see. What the dichotomy is between the original input of information and what "I"/the self sees. We've addressed how this manifests itself through the examples that color might well be a construction of the brain, rather than an objective thing, and the extent to which the brain fills in for blindspots. This really is pretty huge, new information that does take a while to digest and offers many tangents to ponder. Here goes some rambling...In the sense that arbitrary definitions and acceptable/expected behaviors associated with particular colors exist is not really that surprising. It's completely arbitrary that we call colors by their given names. I don't know if I agree with the notion that differentiating what the brain sees from what the self sees would imply less proof that brain=behavior. We've established that there are two ways to process incoming information, namely both with the I function and without it. We know for other behaviors, too, that the I function is not always necessary, so I don't know if this really gives us any new information. I think it's fascinating that for whatever reason, in certain instances information passes through this circuit and others times it does not. We discussed in class that it provides us with the ability to analyze and create. It's quite interesting to construct an understanding of this ability in this way. So, amongst these rambling thoughts, I wonder why and how it has come to be that the I function is or is not involved in what we do, and whether or not it has been an ongoing process of trial and error.

I'm with you, in not seeing any reason in what we've talked about to doubt the brain=behavior principle. As long as we keep in mind that "I" is itself a function of the brain. I'm also with you in thinking (still) that the recognition of "construction" by the brain is a pretty big idea, with lots of implications to explore. And, for that matter, I agree that one of the most interesting things that comes out of all this is how and why the I-function is around sometimes and not other times. We'll talk more about this, and maybe even about where it might have come from in the first place. Any ideas? PG


Name: Jonathan
Username: jball@haverford.edu
Subject: Brain=behavior
Date: Tue Apr 14 00:56:11 EDT 1998
Comments:
Of the two phenomena discussed this week in class the one that has the most relevance to the brain/behavior debate for me is the picture in the mind.

The variability of frog behavior is less interesting because it could possibly be explained using other theories besides the I function. One major problem with the frog variability findings is, it is impossible to actually control all the variables between two given trials so as to make them exactly identical. There will always be a difference between the first and the second trial, even if it is only that in the second trial the subject has a different history. Keeping consistency between trials is made even more difficult when the experimenters cannot be sure what all contributing factors to a behavior are. Perhaps there is a particular neurotransmitter active on the first trial and not active on the second trial; if this NT affects jumping behavior then even if the experiment thinks that the two trials are identical they are not. If we were able to understand and predict all the contingencies with in the organism and the environment down to the sub-atomic level then variability may cease to exist. The question of variability of frog behavior reminds me of an example once given by Prof. Neuman: When a leaf falls from a tree we cannot predict where it lands because we considered its flight path to be random. But if we know everything about the leaf, down to its finest contour, and we knew all about the windís speed and direction we would then be able to predict were the leaf would land which a much higher degree of certainty (this is a pretty rough paraphrasing of a much more eloquent metaphor). It is much the same with behavior, it only seems variable or unpredictable because at any given instance we are unaware of many of the contingencies affecting the organism. Perhaps sciences will never be able to discern all the possible factors that affect a given behavior; every time a new level of intricacy if discovered, there is a new level of variability until there is an box within a box within a box in an infinite regression. As for the picture in the head, it does seem to lead a lot of credence to the notion of an I function. But I wonder how much the picture in the mind is dependent on language. Without languages people would not be able to explain the existence of their internal picture others but also to themselves? Is it possible that what we think of as picture in our mind are images associated with verbalizations going in our private world? In other words do pictures in our minds only exist because we can describe what we are seeing and have seen to ourselves?

Variability as fundamental or ignorance is an interesting issue. As I wrote to Rachel above, there are a variety of reasons to think it may indeed be fundamental (and some reasons to wish it to be so). It is, however, indeed hard (probably impossible) to prove the matter one way or another experimentally (see the end of Variability in Brain Function and Behavior"). Which is, of course, true of most things in science, and leaves one, as always, to instead judge the usefulness of particular concepts in terms of how effectively they raise new and explorable questions.

The relation between the picture in the head and language is an interesting issue. My guess is that the two are relatively independent, since lesions can alter one without substantially affecting the other, since the neural locations probably associated with the picture exist in organisms other than humans, and because, in general, language itself seems to have its origins in-built internal brain processes rather than in experience with the outside world. That's very much a guess, though, with some of the things I'd be inclined to look into to explore the matter further. Very interesting issue, the more so the more I think about it. PG


Name: Allison R.
Username: arosenbe
Subject: behavior
Date: Tue Apr 14 01:17:34 EDT 1998
Comments:

First, I wanted to bring something up that I had been wondering about. Why aren't the photoreceptors in human eyes located in the outermost layer of the retina, so the axons wouldn't have to pass through any other layers forming the optic nerve, locating the point of our blind spot. Octopus have the same type of lens eye as we have, except theirs are more efficient. Their photoreceptors are located in the outermost layer of the retina, eliminating the blind spot and increasing availability of light to receptors. Perhaps there is a particular reason why our eyes developed this way?

Understanding behavior means that we are able to predict any behavior that will occur under specified situations. We have learned that this is nearly impossible. Even with the most highly controlled experiments, behavior is still unpredictable because there must be other inner boxes that aren't being accounted for.

No one factor affects how I think about the brain and behavior more than the next one. I don't think factors can be looked at separately. I don't think any one, by itself, is sufficient to explain the relationship between brain and behavior. It is possible though, that taken collectively, lateral inhibition, color vision, intrinsic variability, etc. can form a basis upon which to account for some behaviors.

For "some" behaviors? Which ones do you want to hold out, and why? Figuring that out is what can get us more steps along the path. Perhaps "predictablity" is more than just additional boxes that "aren't being accounted for"? As for the human (and other vertebrate) eyes, there probably is a "reason", in the sense that one could describe the sequence of evolutionary stages which led to the current state, but there probably isn't a "reason" in the sense of "something which makes it better to have the photoreceptors in the inner layer". So far as I know, the usual "explanation" is that the photoreceptors derive from epithelial elements which, because of the way the eye cup forms, end up lying on what comes to be the outside. Its an as yet uncorrected (for some reason not correctable?) accident of evolution. PG


Name: doug
Username: dholt
Subject:
Date: Tue Apr 14 08:28:57 EDT 1998
Comments:
When looking at each one of the topics individually, I am able to understand and follow along with the notion that the brain does not need the I-function to "see" any more than it needs it to walk (or drive a car!) and in a similar manner, the notion of not a single picture in the head.. but when combining all of the topics, it becomes curious to me as to exactly what does the I-function do? is it solely the location of our individual personalities? are we all hard wired in the same manner that if there were a method of transfering I-functions from one person to the next that you would be able to act exactly as you did before you entered the new body?

very interesting concept regarding blindsight.. i had heard that in patients with severe epilepsy, that severing the connections between the two halves of the brain sometimes suppress the symptoms, but as a result, the patient is unaware of seeing with one eye or the other, thoough is able to identify objects that he did not "see". so if there is no longer a direct connection between the two lobes, how does the information flow?

coming to the picture in the head.. i can grasp the idea that the brain needs several pictures to convert images from a 2-D screen to a 3-D screen, similar in the method of creating a hologram by using several cameras at different angles.. but if the brain has to construct a 3-d image each time it "sees" something.. how does this play a part in memory? when i close my eyes, i can "see" a picture of my house, in the correct dimensions and shapes.. does the brain use the same neural pathways for seeing memories as it does for vision? if not what is the connection? but i am confused on one issue, if there is no picture formed in the brain of what is being presently seen, how can this be compared with what is in the memory? that is assuming that the memory is stored as a single picture, not several different perspectives...

I think that Akino's comments regarding "intelligence" of athletes not being solely measured as to what the I-function is doing is very astute. i can think of many times that the brain is actually computing solutions when the i_function is not working, it happens frequently when trying to remember something, by shifting your attention (i-function?) to something else, you can often remember what you were puzzled by... another example would be waking up with a solution for a problem that you had before you slept.. with this in mind, it is not surprising that the brain can compute without the i-funtion being active.. an area very much interested in by nasa and other space agencies who would love to find methods of putting the conscience to sleep during long space flights but still having the computational abilities of the brain be active.

Hmmm. Lots of interesting ideas/thoughts in here. The relation between the I-function and "personality" is something we'll talk about a bit shortly, but the bottom line is almost certainly that you'd have to transfer more than the I-function to get identical experience/behavior. And yes, blindsight is closely related to split-brain observations, which we'll also talk more about. And yes, it is very true that the I-function is NOT involved in lots of "intelligence", indeed that one sometimes does better without it. Finally, images and memory? Good thought. Would it all make sense if your assumption is wrong? if memory is not "stored as a single picture"? PG


Name: jeremy hirst
Username: jhirst@brynmawr.edu
Subject: no pictures!
Date: Tue Apr 14 08:29:19 EDT 1998
Comments:
The question of whether we need a picture in our head in order to see is exceptionaly interesting. What is seeing? Seems to be a question that goes along with this idea that we may possibly not really need to have a visual brain image in our heads in order to manuever in the world.

Is seeing being able to describe the colors, shapes and specific distances objects hold in the universe around us? or is seeing somthing simpler, just being able to get from here to there, or point (reliably) at on object, but not really be able to describe it in detail. It seems both phenomenon are seeing, just on different levels. One is conventional, full sensory seeing while, the other is seeing with a substantial handicap.

Being able to point towards and object with out having a picture of it in your head seems that it would require a lot of faith in ones nervous system. To let the I function rest and allow the silent nerverous system to operate. How often do we trust that part of our bodies knowingly, letting our I function really let go and totally rely on the nervous system which does get to ever "hold the floor" in our brains. I don't think I let that happen too often.

At the eye doctor seeing is being able to identify letters on an eye chart. But I think seeing is more than that. For me it is being able to experience the emotion of the scene, to feel the mood around me. In this sense seeing is much more then the picture in my head, it is the words or sounds carried by my ears, it is the touch of other people or the sensation of temperature on my face. As smell is some large percentage of taste, these other sensations are a large part of seeing for me. So, if the picture is absent from this mix does that mean I am not seeing? Can one missing variable cancel the entire experience?

I don't think so. But I also dont think it would be correct in calling it seeing. Pictures have always been what is referred to as seeing, and removing those from the equation would make the experience equal somthing else, likely as influential, just different.

Interesting array of thoughts, both general and specific. Certainly one of the issues raised by blindsight (among other phenomena) is the possibility that it might sometimes pay to let "our I-function really let go and totally rely on [the rest of] the nervous system". Which fits with some of the discussion above about athletic performance and intuition? On the other end of the spectrum, it is interesting to try and imagine "experience" without the picture in the head. Given all the other things you say experience consists of, maybe an absence of the picture in the head wouldn't be so significant? PG


Name: Rupa Hiremath
Username: rhiremat@brynmawr.edu
Subject: hmmm...
Date: Tue Apr 14 09:33:58 EDT 1998
Comments:
Hmmm...I do wonder a lot about vision, pictures in our heads, and memories. From class, I understand a little bit more about how one does not need a picture in her head to see. I believe that the end result of our eyes seeing is our interpretation of the image. Yes, we can all SEE the same object, but HOW do we see it? I really feel that the I-function does play a part in the visual center of our brain. I guess my question may be, how do vision and memory correlate? Do they correlate at all? Where does imagination come into play?

However, then I thought about our discussions in class about other species and their vision. They see differently than us, yet they do have memories, but to a lesser degree. This led me to become a little confused about vision and memory.

I also wondered if there were some connection between the degree of visual acuity and memory mass. In other words, is it true that those who can retain more information have poorer eyesight and need to wear glasses/contacts lens? My curiosity stems from the old myth that smarter people need to wear glasses. :)

Oh, I also thought that our other senses (smelling, tasting, hearing, touching) may come into play in regard to correlating with memory. I was curious to know how they fit into the big picture. I do not think that these senses would be as complicated as our sense of sight, but you never know.

Lots of people interested, like you, in the memory issue. We'll get to it (imagination we did a little bit, and will get back to). Now, why exactly should people with poor eyesight retain more information? Because they need it more to construct pictures? Interesting. Not impossible. Would be worth looking into. PG


Name: Eliza Windsor
Username: ewindsor
Subject: division of labor
Date: Tue Apr 14 10:08:50 EDT 1998
Comments:
I'm still trying to figure out the relation of the I-function to the rest of the nervous system and the body. Therefore, I will just write down some of my thoughts rather than make a cohesive argument.

We've talked about how our eyes mess with the inputs they receive before passing the information on to the I-function. At the same time the info "I" get is closer to reality than straight data inputs from the eye would be. At least I can manage to not walk into walls and I can relate to other people. This makes me think of bats who use sound, and certain aquatic organisms that use electromagnetic fields to orient themselves within reality. Blind people can use other senses to understand reality. One big point from our discussions of vision seemed to be that the nervous system is processing the inputs it receives about reality without the help of the I-function. Therefore, how can we be sure that the reality presented to us is true? After all, the I-function does make important decisions and exercises considerable control over the body. If it is responding to incorrect data then the body may suffer. I think that what we have learned with regard to vision shows that I am not totally in control; "I" am at the mercy of my body. This is hard to accept because I think of my body as something that works for me (it works for my I-function). The importance of the body is linked to its necessity as a support the I-function. Most scientific, philosophical, literary, and historical endeavors are driven by and for the I-function. It is hard to accept that the I-function is so dependent on the body which is ultimately unreliable. The body may start out, or become, handicapped physically or mentally. This means that the I-function is handicapped physically or mentally. Ultimately the body dies out taking the I-function with it. Mankind has tried to work against this by building great monuments and writing for posterity.(I feel like I've said this before so I'm sorry if this is just repetition)Our study of both the input side of the nervous system and the output side of the nervous system show that we don't necessarily need the I-function for either. So what is it there for? I don't have any concrete thoughts about that yet.Another big question for me is, what if it wasn't there? One human ambition seems to be to extend the life of the I-function beyond the death of the body through works of posterity. There is some sense in which aristotle, plato,shakespeare, and marie curie among others live on. Organisms can survive without an I-function, but it seems almost pointless without one. I have more thinking to do on this subject.I seem to be just stating the obvious. (note: I've used the word body to refer to everything about a human, including the rest of the nervous system, which isn't the I-function)

"I" don't think you're stating (or repeating) the obvious at all. To the contrary, it seems to me you're raising and wrestling with a very interesting and important set of issues. Indeed, "most scientific, philosophical, literary, and historical endeavours" are, it seems to me, "driven by and for the I-function". So the notion that the I-function is a restricted and not entirely in control part of the nervous system (and rest of the body), if its true, has not only implications for individuals but broader ones as well. The notion of human ambition including efforts to "extend the life of the I-function" is I think not only a good characterization but may also be a useful way into the question of what the I-function does, is good for. If I don't say something along these lines in the next weeks, remind me? PG


Name: Rob Miller
Username: rmmiller@brynmawr.edu
Subject:
Date: Tue Apr 14 10:48:01 EDT 1998
Comments:
Thinking about the picture created in the brain as we look around the world, it is interesting that much of what we see may be conjured up by our brains. This is an amazing leap of faith for many of us. It is hard believe that our brain can fill in blank spots and deceive us into thinking a complete picture exists, when all along we have thought that we see everything there is to see. But maybe we can start thinking of the images created in our heads though the processes of lateral inhibition and seeing through blindspots as similar mechanisms to the mechanisms which create dreams. We all have known for a long time that the brain can create images and show them to us in our dreams. Is there really a difference between how the brain create those images and how the brain fills in gaps with our sight perception? I don't know the answer, but maybe thinking our how the brain perceives light and dreams in the same context can help us be more familiar with the strange newness of these concepts. In a sense we can think of all reality as a dream, but one of which we are conscious. The point is that the brain has many ways in fooling the I-Function into believing what is real. Recognizing what is real is difficult because we trust our eyes too much. But it is important to remember that the eyes are not the only way the brain can make a picture.

Very good point, and one we will get to quite shortly. Yes, indeed, the brain can (and does) not only fill in images but create them entirely. Interesting question to think about (and we'll discuss): what is the state of the I-function during dreaming? PG


Name: Zach Hettinger
Username: ahetting@haverford.edu
Subject: blindsight and memory
Date: Tue Apr 14 10:59:39 EDT 1998
Comments:
Of all the things that we've discussed in the last week I think that the construct of blindsight has made me think the most. I think what struck me was that a picture in your head is not necessary for life. That there are many "advanced" animals like frogs that can see, but do not have a picture in their head. So it seems that we could exist without a picture in our head, yet at the same time that picture seems very closely linked to many of the things that we take pride in as being human, such as reasoning and creativity.

So how important is the picture in the head to the ability to have a memory, or can one not have a memory without the picture in the head? Obviously a blind person is capable of retaining sounds and tactile information, their memory does not just vanish with the loss of sight. But did memory evolve as a result or concurrently with the evolution of the picture in the head, or is it an independent function. I always see young animals, mainly mammals, on nature shows that are learning about their environment and exploring what they can and cannot eat and how to fight. Those things that they learn in their early years they must remember for the rest of their lives in order to survive. So is the assumption then that without a neocortex an animal has neither a picture in their head nor a memory, thus leaving the animal to interact with the world as it sees it and never learn from any of it's experiences? Can frogs not learn?

I was also curious about how much this has been looked at in humans. Obviously you cant go running lab experiments on humans and damaging their neocortex, but of those that do have damage, how complex is their blindsight? Can they do more then point at a light? Could they walk down a street without assistance and avoid obstacles in their path? Although you pointed out that we can use blindsight in our everyday lives when we dont even realize it, like while driving, how much could we revert back and depend on a way of seeing that we haven't ever solely depended on as humans.

Blindsight is a relatively recently described phenomenon and so still both somewhat controversial and understudied. There's a recent review in Brain if you want to see more or less where the field currently is (P. Stoerig and A. Cowey, Blindsight in man and monkey, Brain 120: 535-559, 1997). Yes, people with visual cortex damage can do more than point, how much more is still a little unclear (but clearly depends on how one elicits performance). I'm not sure anyone has looked at the matter naturalistically (walking down a street), but there may be anecdotal information on the web. What is certain is that people with blindsight don't report a "hole", just like one doesn't see the optic nerve head. We'll talk more about the relation between seeing and memory, but all sorts of animals (including frogs) are certainly capable of learning (which is probably a different thing). PG


Name: Donald ball
Username: dball@brynmawr.edu
Subject:
Date: Tue Apr 14 11:07:05 EDT 1998
Comments:
As the course progresses I become more and more amazed at how much of our perceived reality is in fact the brain's best guess about the information it is receiving. The fact that color vision is a function of the brain assigning categories because of differences in intensity and wavelength of light and that color is not an intrinsic part of the world is quit a shocking discovery for me. Obviously, the relationship between brain and behavior becomes increasingly more complex. We act based on what we perceive, yet what we perceive is not always 'real'. It is fair to say then that making predictions about behavior even when trying to control for all environmental circumstances is an extremely difficult thing to do. The behavior that one exhibits has much to do with the input received, as well as with previous input that has been stored as the NS has reacted to similar situations in the past. So, not only are you dealing with variability in what the brain actually allows you to experience but there is variability in response due to previous such 'uniquely interpreted circumstances. The fact that human behvaior then can appear to be so random and nonsensical actually seems to make better sense given what we have discovered about the way the brain deals with information. The same people experiencing the same phenomena can react entirely differently. Scary proposition but that is also what makes unique.

And, perhaps, what makes each person valuable to every other, since no one's picture is perfect? And maybe its not non-sensical, but rather a highly effective (the most effective?) way of making sense of an inevitably uncertain world? Maybe its the world that's scary, rather than what the brain does with it? PG


Name: Emily
Username: evarani@brynmawr.edu
Subject: depth perception
Date: Tue Apr 14 11:45:36 EDT 1998
Comments:
In recent weeks we have touched on two subjects that have an interesting interconnection. We have stated that images coming from different sites onto the retina allow for 3-dimensional vision (= depth perception) of a picture. We have somewhat related this topic to the idea that the brain contains compensation mechanisms for allowing "sight" within the brain that differs from "the picture". We discussed an experiment where a blind man was able to indicate the direction from which came a light. For me, this raises the question of whether the man could indicate the distance of the light as well. One would think so since his optical system was not damaged, merely the pathway carrying the signals was damaged. However, with a system as complex as this, many other factors must play parts in regulating the messages from the eyes to the brain.

VERY interesting question, to which I don't know the answer, and suspect no one else does either. There is a tendency to presume that stereopsis depends on visual cortex (the area damaged to produce blindsight), but other areas of the brain also get input from both eyes. And there are, of course, other cues for distance judgement, as we talked about. Much make an interesting research program out of that idea. PG


Name: zermatt scutt
Username: mscutt
Subject: Impossible 'objects'
Date: Tue Apr 14 11:51:41 EDT 1998
Comments:
This part of the lecture really fascinated me. I knew that our brain was capable of imagining all sorts of things, but it didn't occur to me that part of its sophistication involved creating things that are physically impossibe, that is as far as we're concerned anyhow. I was also intrigued by our inability to trace down the path to the picture in our heads. As it stands, "Where is the picture in our heads?" remains a mystery. It was explained that scientists spent years of research following tracks that as far as their logic were concerned should have led to the location of the picture. But the picture was nowhere to be found. This brings me to the same kind of struggle I've been having with the "I-Function" throughout the semester. You could also say that the "I-function", although we have overwhelming evidence of its being, is nowhere to be found. So I've come down to a couple of conclusions, either they're hiding from us or maybe simply our approach in seeking them out is interfering with us finding them, or by failing to meet our expectations of what they should be, they go unnoticed by us.

I wondered if it could be that the picture is all over, not contained or confined to a specific region of the brain as we would expect. The same observation can be made of the I-function. Could it be that it is all encompassing of our brain, at the same a property of our brain as it is the entity encompassing not only our brain but our being alltogether. Could it be a spirit, not physically defined? Is the idea of the spirit an expectation of the science of biology? Could the I-function be as physical in that it can be studied and anylzed by us when we examine the brain and the human body as it is spiritual and undectable by our science? Are we putting too much constraints on 'what is' by our demand for physicality? It doen't necessarily reduce to a question of magic but rather to a question cannot by its nature be seen and detected in our laboratories? Do we stop researching then, by all means no. Maybe simply we aught as scientists not to get too caught up and emprisoned by our laboratories and look beyond for these answers.

Very interesting, very sophisticated set of thoughts. Yes, we can't find the picture using certain techniques, nor (perhaps, actually you've anticipated the conclusion) the I-function using particular techniques. But that doesn't mean that it isn't there ... we need "not to get too caught up and emprisoned by our laboratories". Perhaps our laboratories have been designed to look for things at particular places and, as you suggest, some things are different, being instead in lots of places at the same time. No, that's not magic (it doesn't even necessarily mean not "physical"), but it does mean we have to look (and maybe even ask the question) differently. PG


Name: Katie Cecil
Username: kcecil@brynmawr.edu
Subject:
Date: Tue Apr 14 12:12:36 EDT 1998
Comments:
Thinking about it, the thing that struck me most curious in the last few weeks of lecture was your mentioning that some people, or more specifically women, have four color pigments in their visual system. I just assumed that everyone's concept of color was pretty uniform, but if this finding is true, I'm obviously wrong in my assumption. I got to really wondering how my perception of color would vary if I saw with four photopigments as opposed to three. Would it make the color of the sky different? Would I be more apt to wear yellow? Would that make me a better interior decorator? Obviously, there is no way of determining these things, but I am still quite curious about how ones perception would be different with an additional photoreceptor. How would one go about determining the difference?

Furthermore, I've always seen vision as rather concrete. You either see or you don't or the picture is just blurry. I recognized means of sight is variable, after all I was very happy in second grade to learn that I don't have bug eyes and never will. Still, talk about the cerebral cortex never seizes to challenge me. I'm still not sure what to think about the significance of the picture in my head, but I'm glad it's there.

I'll end with a personal anecdote from the other day. Last week in another one of my classes we took the army alpha, an "intelligence" test administered to draftees during WW1. My professor made us take it to demonstrate that it was in fact really more of a literacy test with extreme cultural bias, but I found it personally interesting for other reasons. One of the subsets involved a series of sentences in which the order of the words was scrambled. The object of the test was to determine whether the sentence was true or false in as short a time as possible. For example, the sentence "grass blue is the" would be false. I completed the test in literally about half the time of the rest of the students in my class with 100% accuracy. I am dyslexic. Thus I have been wondering if, how, and on what level this test was effected by something which usually sets one at a disadvantage in timed measures of literacy. Could it be the way I'm seeing the words or is it something deeper in my perception? What do you think?

I think I'm fascinated, and would like to know more, from lots of points of view. Not the least of them is the contrast (?) between what I assume are your own experiences and your simultaneous presumption that things look the same to all people. Can you describe what writing looks like to you? I wonder if it looks different to someone who's not dyslexic (and whether such a difference could come out from "describing what it looks like"?). I'm equally intrigued by the test anecdote. One of the problems (so far as I'm concerned) with categories like "dyslexic" is that they are created in recognition of a "deficit". My guess, though, is that virtually all variants of nervous system organization (of which "dyslexia" is presumably a set) have more wide spread effects, so that there are probably enhancements associated with them as well. It would be very interesting to look into that by trying to define more precisely what the "enhancement" might be that your experience suggests exists. PG


Name: jenny sabo
Username: jsabo@brynmawr.edu
Subject: Pictures in the Head
Date: Tue Apr 14 14:41:55 EDT 1998
Comments:
I associate pictures in the head with imagination and daydreaming in which you don't necessarily have to "see" something. Furthermore, in order to see you don't have to have a picture in your head. What about when you dream? During a dream, you are not seeing anything but you definitely have pictures in your head. These 3-D pictures in the brain have a great impact on behavior--I know sometimes my dreams influence my behavior. Also, in my daydreams I create scenarios and how I would behave in them. Anyway, at the moment, I really don't have anything else to say about these pictures...

You've said plenty to take us to the next discussion. Yep, pictures without optic nerve activity, which influence behavior, and in which you are involved. Let's see what we can do with all that. PG


Name: Daniel Casasanto
Username: dcasasan@brynmawr.edu
Subject: Weekly Essay #8
Date: Tue Apr 14 18:10:08 EDT 1998
Comments:

The bilateral tectal outflow model proposes two sets of descending pathways capable of generating visually elicited prey orienting turns: crossed pathways responsible for turns contralateral to the lesioned hemisphere of the brain, and uncrossed pathways responsible for turns ipsilateral to the lesioned hemisphere. The relevant articles (Kostyk and Grobstein, 1986) defend rigorously the existence of bilateral uncrossed descending pathways. The existence of crossed tectal outflow pathways, however, was documented half a century earlier, and required no defense.

Although I have known since elementary school that animals, including humans, process visual input in the hemisphere of the brain contralateral to the eye that receives it, I still do not understand why. Light coming from the one side of an eye is refracted so as to stimulate the retina on the opposite side of the eye. So what? This observation seems insufficient to explain pathway crossing in the visual system. Furthermore, crossed pathways are not limited to the visual system. It is common knowledge that the right side of the brain controls limb movement on the left side of the body. It seems unlikely that this organization is somehow related to the refraction of light by the eye's lens. Perhaps the crossing of pathways is a means of interconnecting otherwise remote anatomical regions. This might result in a sort of neuronal "hybridization." Disparate neurons often display differing intrinsic functional characteristics. Perhaps their interconnection engenders emergent properties which would not result from the interaction of more proximate neurons that display similar functional characteristics.

Alternatively, crossing pathways may enable the brain to capitalize on the sensory information it receives via "cross-referencing." Already in our study of neurobiology we have seen several illustrations of the brain gathering information on a single phenomenon by various methods, and then comparing the data to construct a coherent interpretation. In the visual system, examples of this information-synthesizing process include distance perception via binocular parallax, and color perception via the comparison of the distinct yet overlapping spectral sensitivities of specific photopigments. Whatever the cause, the crossing of pathways must result in some beneficial property of the nervous system which would be impossible via uncrossed pathways alone.

As I said when we talked today, crossing is a problem that's been on my mind for fifteen years or so. "Neuronal hybridization" is interesting, but I'm not sure enough what you mean by "engenders emergent properties which would not result from the interaction of more proximate neurons ..." to give up another fifteen years of thinking about the problem. Glad you're interested though. PG

.


Name: RIT
Username: rtrimiew@brynmawr.edu
Subject: The same isn't the same.
Date: Tue Apr 14 20:00:55 EDT 1998
Comments:
I can't seem to get it out of my head that when all of the experiments are carried out (from the Harvard ones on crickets, to those done on frogs, to our own experiences), that there is a fundamental difference through each trial. Each time a trial in the experiment is done on an animal, the animal has had x amount of experience in the same situation. So even if all of the variables do not vary 8), the animal has. The first time a worm is presented, it is a new experience, the second time, the animal can remember what happened the last time and change/not change accordingly. The more experiences with the worm, the more memories. As we learn our nervous system changes. Each time we experiment with the frog, their nervous system is different and thus the frog is different. There is no way to avoid this.

You told me that the important part was the input and the output (I think that was part of what you were telling me), but it is essential to put the same input into the same thing and measure the output, not outputs of different things. The animal may always want to accomplish the goal (get the worm) every time, but may differ the means to learn. With your driving example, you drive a different way because the day before you went a certain way already. I wonder if there is a pattern in the progressive hops/rotation of the frogs, if they hop in a systematic fashion to discover the best way of doing something. OK, I think that we are talking about the same thing. But, does the Harvard Law essential say that an animal will change over time so that their actions can not be predicted because we do not know all of the data of their lives? Although, I thought that you said that even if we had all of the data, we could not predict their next move. But, if we had information on all of the connections in the NS, the properties of everything (molecules, cells, etc.), and knew all of the alterations made over the life, couldn't we predict the actions? We can predict the behavior (get food) with reasonable accuracy. If we had more data, couldn't we predict the move?

Does this relate to humans? You must combine the experiences in life (alterations made to the NS), with the genetic information? What is the I-function in relation to this? Can it override the normally predestined response? I remember playing Find Serendip. I started at the first level and once I understood what was going on, I could guess correctly with only a few guesses. As I moved up the levels, some I got on the first try, while others took 3 or 4 times. However, no level took more then 6 or 7 guesses. The game was supposed to be random though. I think that if we knew everything about the computer, we would be able to predict the next hidden serendip location. When I play tetris, after awhile I can predict what the next move will be, though it is random. Are animals the same? Does our I-function allow us to know what we should do(based on our knowledge of our lives and everything) and not obey it and do what ever we darn well please? I was thinking of how we could test this. I was just reminded of twin studies and how two twins that had grown up together (and sometimes apart) could be taken into different rooms and asked to say something random. The thing that I read said that a lot of times, that random thing would be the same thing that the other twin said in another room. I wonder, if the twins were told what was being studied and that they should pick something random that their twin would not say (to rely on what they know of themselves and the other twin and what the twin would be likely to say) if they could pick something different from the other twin or if it would still be the same. I think that they could use their I-function to pick something different. I wonder if other animals could.

Sorry, I did not think through this essay as I usually do before I wrote it. These are just thoughts I had about it.

No apologies needed at all. Very interesting thoughts, wrestling with very real and significant issues. My guess is that we and frogs are NOT predictable, even if we knew all inputs, and that's important but that's very hard to prove (see my replies to Rachel and Jonathan above). Twins are indeed are interesting case for thinking about all this, and we'll talk more about that. And about your intuition that the I-function plays a role in increasing unpredictability. PG


Name: Alicia
Username: aebbitt
Subject: "Deaf-Hearing"
Date: Wed Apr 15 20:53:41 EDT 1998
Comments:
While thinking about "blindsight", I started to wonder if our nervous does something similar with all of our senses, particularly hearing. Is there such a thing as "deaf-hearing"? Is it possible that sometimes our nervous system "hears" something, that our I-function does not. When we are asleep, or when someone is unconscious, there are definitely still sound waves travelling around. If our nervous systems, specifically our ears and the mechanisms in our bodies that pick up sound waves are working properly, then do our nervous systems "hear" sounds even when we are not aware of them? Taking "blindsight" into consideration, this makes perfect sense to me, but what I wonder is why are we not aware of these sounds and when do we become aware? Why are some people deeper sleepers than others? What goes on in the nervous system of people that wake up easier when they hear sound, that makes allows their I-functions to be aware of sounds more easily? Another question that comes to my mind is what goes on in a deaf person's system? Do they actually "hear" sounds and their I-functions are simply not aware of these sounds? I guess this comes under the same realm of the unanswerable question about whether a paraplegic can feel someone touching their foot. Yet again I have no answers to these questions, but found them quite interesting. I hope you all find them interesting as well.

Very. And yes, I'm quite sure there is "deaf-hearing" in real life. Whether a comparable clinical syndrome (following a brain lesion) has been described I don't know and is an interesting question. There are though a variety of other comparable syndromes outside the visual realm, including anosognosia, a denial of a deficit involving parts of the body. You might enjoy an interesting finding suggesting there may be, in addition, denial of deficits in corresponding parts of the bodies of other people. We'll take more about some interesting possible implications of this in class. PG




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