Biology 202
Neurobiology and Behavior
Spring 2004

Forum 14


Name:  prachi
Username:  pdave@brynmawr.edu
Subject:  hallucinations
Date:  2004-04-20 08:48:22
Message Id:  9474
Comments:
One thing that I would find interesting is the relationship between visual hallucinations and sight. Do they have any link to one another or is the "visual" aspect of the hallucination entirely within the brain, a complete creation that is divorced from actual sight?
Name:  Emma
Username:  eberdan@brynmawr.edu
Subject:  thoughts
Date:  2004-04-20 09:17:42
Message Id:  9475
Comments:
Last year when I was up very late working on an Orgo project I hallucinated a giant spider on top of me. It is the only time I have ever hallucinated and I wonder what caused it, was it because I was so tired(It was about 3 am and we had been working for hours straight)? Or was it because at that point my brain was simply too over worked? In people who do not normally hallucinate what causes an isolated hallucination?
Name:  Chevon Deputy
Username:  Anonymous
Subject:  My Mind's Playing Tricks on Me!!
Date:  2004-04-20 09:34:54
Message Id:  9476
Comments:
I enjoyed the exercise of examining different ambiguous pictures, because everyone had their own interpretation of what was in the picture. Not only did people have their own interpretation, but they also tried to convince others to see what they saw. In some instances, it worked. We concluded that your brain is actually guessing what is in the picture. However, if someone convinces you of what is in the picture, is your brain still guessing or have you just "forced" your brain to guess what you want the picture to be? I understand that the second set of pews is to resolve ambiguity. Is this in combination with your brain guessing or is it independent?
Name:  Katina Krasnec
Username:  kkrasnec@brynmawr.edu
Subject:  
Date:  2004-04-20 09:50:45
Message Id:  9477
Comments:
Hallucination and voices are common side effects of mental illness, such as bi-polar disorder, schizophrenia. My questions is, as there are many different types of hallucinations, such as auditory or visual, what, neurologically, would this do to the function of these senses normally? Is there something within the brain that creates these vivid pictures or sounds? It must be, but what part of it comes from the subconcious, and being unaware?

As for dreams, many people cannot remember them. But what occurs when a visiual que, or something similar that may have occured in the REM state of dreaming, would occur in real life? Would it been seen as deja vu, or just a normal reaction?


Name:  Natalie Merrill
Username:  nmerrill@brynmawr.edu
Subject:  sense/see
Date:  2004-04-20 09:58:53
Message Id:  9478
Comments:
We seem to be talking about two different things: the abililty to SEE the world around us and the ability to SENSE the world around us. It seems to me that this SENSE is a much more intense, emotive and probably unreliable perception. But it is this SENSE from which we are able to detect social cues, observe expression, and probably respond to things such as music, art and nature. I wonder what part of the brain this might occur in, and how it is connected to vision.
Name:  Emily
Username:  ehayesro@brynmawr.edu
Subject:  Exceptions to Blindness
Date:  2004-04-20 11:16:21
Message Id:  9480
Comments:
Amy talked about the sharpened "other" senses of people with an impaired sense: Blind people with a heightened sense of touch, for example. I don't remember where I read this, but in these people, their "visual" brain centers (the primary visual cortex, for example) are actually "invaded" by information from other senses. I posted before on a study done on this phenomenon in infant ferretts. I suppose something like this must also happen in humans who are blind and need their senses of touch and hearing to create the world because their eyes, or rather their visual pathways, cannot.

This also makes me think of another case I've heard about. I believe it was on an episode of Nova, or on the Discovery Channel. Neurologists were studying a man who is totally blind, but who can sense motion. You can move something in his field of vision, and if the movement is great enough, he can "see" it. He can't tell you what it is, because he can't see the object itself. But he does "see" that it moves. How does this work? I know that there are different neurons devoted to the detection of light v. movement, but how are they getting their information? I'm pretty sure these specialized neurons lie in the brain, and isn't the only information going to the brain light information from the retina? This fascinates me. This man has no capacity for what we think of as sight: the detection of light. But he can detect movement. Doesn't this have to have something to do with light, because the object he "sees" moving are detected by his brain in some way by the light they reflect? I can't figure out how this would work.


Name:  debbie
Username:  dyi@brynmawr.edu
Subject:  
Date:  2004-04-20 11:44:10
Message Id:  9481
Comments:
I was just thinking about how color is an arbitrary construction of the brain. When I see the color Periwinkle on a Crayola crayon, I see the same color everytime, and I register the color as Periwinkle (after learning what Periwinkle looks like to me). Do different people see a different color than I see (since our rods and cones are presumably different)? It seems like they would and just like me, they see the same color each time and have learned to recognize it as Periwinkle.
Name:  Emily
Username:  ehayesro@brynmawr.edu
Subject:  Exceptions to Blindness
Date:  2004-04-21 23:02:24
Message Id:  9530
Comments:
I've been wondering about Debbie's color question as long as I can remember: Is my purple her purple? Or does what she sees as "purple" look to her like what i call "blue"?

As much as I would almost like the latter to be the case, just for the coolness of it, everyone seeing trees differently, but as totally normal to them, it musn't be the case. While there must be some variation in our rods and cones, color is a construction of the brain based upon wavelength of light. The wavelength going into the eye is the same. So it should be seen the same way.

....But, since I'm a good bio 202 student, I must say, "maybe not." Because we've determined that what we see and what's really there aren't perfectly equal...but it seems to me that as a principle of physics, color must be seen mostly the same by everyone. Otherwise color cooridnation would never work, right?


Name:  elissa
Username:  eseto@brynmawr.edu
Subject:  sight and color, etc
Date:  2004-04-22 09:43:22
Message Id:  9543
Comments:
I think that perceptions of color is different for people. I, for one, lack any ability to color coordinate. People's perception of color is based on how they learned about that color, but since they're seeing it only through their own eyes there is no basis for comparison for them. And what about color blind people?

And also going back to Emily's post, "You can move something in his field of vision, and if the movement is great enough, he can "see" it. He can't tell you what it is, because he can't see the object itself. But he does "see" that it moves. How does this work? I know that there are different neurons devoted to the detection of light v. movement, but how are they getting their information?" I don't think that he actually can see the movement, but it's something that you can detect with your other senses. With that, could it be that his skin is so sensitive to touch that it can actually feel the movement of an object with the change in air current/pressure around him? It's not surprising that this man can detect movement, even though he's blind.


Name:  Student Contributor
Subject:  The blind can "see"
Date:  2004-04-22 18:51:53
Message Id:  9557
Comments:
I was thinking about Elisa's posting. We all know that when a person looses one sense, the other four become heightened. This blind man might sense the movement of a certain object from the way it affects his other senses - as Elisa said, the moving air current, hearing the object move, et cetera.

In another class, we were talking about how blind people sometimes get restorative surgery to get their sight back, and then have a hard time adjusting. Their understanding of depth perception simply isn't able to extend to their sight. Many end up blind-folding themselves and using their walking sticks in order to understand depth perception. Just thought I'd contribute that ...


Name:  Jean
Username:  jyanolat@brynmawr.edu
Subject:  
Date:  2004-04-22 21:43:14
Message Id:  9562
Comments:
In response to Emily's comment, even though the same wavelengths of light are being sensed and the same sets of information are being sent to the brains of two people, their brains might interpret the given information differently. Therefore I would probably have to answer yes to "Or does what she sees as 'purple' look to her like what i call 'blue'?". I think this difference in interpretation is a definite possibility.
Name:  Liz
Username:  epowell@brynmawr.edu
Subject:  color blindness
Date:  2004-04-22 23:41:22
Message Id:  9563
Comments:
After the discussion in class today about color blindness, I was curious as to how those with different color definciences observe things differently. I found this link that shows how an image appears to those with different types of color deficiency...
http://webexhibits.org/causesofcolor/2.html#vissamp
Name:  Eleni
Username:  ekardara@brynmawr.edu
Subject:  Color comments
Date:  2004-04-24 00:08:01
Message Id:  9577
Comments:
First off, I was wondering about non-spectral hues (such as pink and brown). I didn't quite understand how they were created. I know all color has to do with the cone system, but are non-spectral hues also connected to the rod system and brightness? I was thinking that if pink was just a faint red, then it could have something to do with intensity/ brightness as well as color mixing from the 3 broad bands.

On the subject of the 3 broad bands, I found it interesting to discuss that colors are created by just altering the ratios of these 3 bands. I understand that this is how it works in our brain and why color is not an aspect of physical reality in this case. I am having a little trouble accepting this, though. In one of my Chem courses, we studied the colors of compounds and how color is related to electron transitions and ultimately energy. Energy is a very real concept that can be measured so I feel like color is not just all perception-or rather, it doesn't matter if it is perception in this case-because with the compounds, color just depends on the wavelength, not the actual color that you see. So, if you think of color as energy, doesn't it seem to be a physical concept without (much) ambiguity?


Name:  Dana
Username:  dbakalar@brynmawr.edu
Subject:  Childhood Color Theory
Date:  2004-04-24 21:45:59
Message Id:  9582
Comments:
I remember sitting with my friend when we wre 10 or 11, and discussing this color theory stuff. We were asking whether "blue" looks the same to each of us, whether we maybe learned to call the color of the sky "blue," but if I could see it through her eyes I would identify it as "green."

It seems that the answer is no, they arent the same, or you cannot show whether thay are or not. This is because of a lack of outside verification, of a truth. If color exists only as a perception then there is no "reality" to verify it against.

Daniel Dennet writes :    Vision involving spectral differences (not just luminance differences) turns out to be wonderfully strange, and I think there has been enough astute canvassing of the prospects so that we can be pretty sure that any theory "of color" will have some counterintuitive bite-the-bullet implications in one corner or another, but I am surprised at one particular bullet B&H decide to bite: unknowable color facts about, for instance, which chip is (really) unique green. For this to be a fact, there has to be some standard of correctness which isn't just majority rule or something like it. But it isn't just that we don't yet know any such standard; we have good reason to believe that there couldn't be one, any more than there could be an unknowable fact about the correct pronunciation of the word "controversy" (who really has it right, the Brits or the Americans?). B&H have a clear understanding, it seems,  of the coevolutionary coordination of color vision and reflectance properties, and it would seem to follow from this that the 'ideal' of a unique green independent of (human) physiology is as indefinable as the ideal of correct pronunciation of a word independent of human social practices.  Color isn't like distance or horizontality for the simple reason that distance and horizontality properties didn't co-evolve with spatial vision. Yes, people can make mistakes about unique green, and about how "controversy" is pronounced, but that doesn't mean that there is a people-independent way of fixing what is right in these cases.
 (Available: http://ase.tufts.edu/cogstud/papers/byrnehilbertbbs.htm)

This is really cool
 


Name:  Amy Gao
Username:  agao@brynmawr.edu
Subject:  on the subject of senses
Date:  2004-04-26 20:03:01
Message Id:  9611
Comments:
I think perhaps some of us have experienced something like this: our backs are turned, and someone approaches us from the back, but yet we are able to "sense" that person's approach even though the person was being quiet and did not make any noises that would have alerted us to their presence. How were we able to "sense" something like this? It must not have been the visual cues since the back is turned, and if the person was being very quiet no humanly audible sound would've been made.
Name:  Shadia
Username:  cbelhamd@brynmawr.edu
Subject:  Synesthesia
Date:  2004-04-26 21:14:44
Message Id:  9615
Comments:
Last week, a group of us were all cramming/studying for an Orgo exam when a friend casually mentioned that she found mechanisms with nitrogen easy to remember because of their "orange color". This surprised us—until she mentioned that ppl have told her she has "this thing called synesthesia"; i.e. she "sees" color in letters. She told us how she couldn't understand how other ppl could possibly remember things, without being able to remember their colors and started to tell us the colors of the letters of the alphabet. I had heard/learned about synesthesia before but hearing her talk really cemented the idea that color is not an aspect of physical reality. I have to admit I was a little skeptical but she went even went through the letters in our names—the same letter always corresponded to the same color. She explained that my name is "yellow" while say, Anna's is brownish orange and her own is blue. I now have no doubt that her "yellow" is quite different from my own—it might even be identical to my "black". The interesting (and scary) thing is she had always assumed that everyone else was doing this—it wasn't until she was 18 and learned of the "phenomenon" in a HS science class that she asked around and discovered she has a different way of seeing things.
Name:  Erica
Username:  egraham@brynmawr.edu
Subject:  
Date:  2004-04-26 21:38:34
Message Id:  9617
Comments:
Just a comment/question on the (non)existence of color. I was thinking that someone somewhere had to initially recognize the appearance of color in their world, and it pretty much baffles me how there exists such a universal concept as color. There is no way of fully knowing what is and whether it's called the right thing, but it's interesting to me that a majority of the people in this world can perceive one thing in the same way. If there is no agreement on the specific color of something, at the very least there is a general consensus on it's presence as color, be it a creation of the brain. But, the question still remains whether or not we would know the concept of color had we not been taught it. Would we just call it something else, and how would we know enough to know that it doesn't really exist, as the case may be?
Name:  Ginger K.
Username:  gkkelly@brynmawr.edu
Subject:  Further Color Blindness Musings
Date:  2004-04-26 21:57:10
Message Id:  9620
Comments:
I have been very impressed by everyone's comments regarding color blindness. I wanted to be able to contribute something, but had no idea as to what angle I wanted to pursue. After doing some googling I hit upon a site: About Color Blindness . The pages on the site were written by someone who is color blind. I was amazed by the way one's life can be changed by something so basic as not seeing red. The author mentions not being able to tell if your food is done, not knowing how you colored in a coloring book, not being able to read the weather channel maps well, ect.. You're probably wondering why I bring this all up. Not to seem dramatic, but it is important that we consider how the conditions we study impact peoples' lives. We are constantly considering the nervous system and the mind in terms of the big picture. Yet, in my mind, peoples' personal experiences are just as vital to neuroscience. Thanks to everyone in this class for contributing. I've learned a lot from you all.
Name:  erin
Username:  eokazaki@brynmawr.edu
Subject:  
Date:  2004-04-26 23:11:19
Message Id:  9623
Comments:
I find the notion of reality and its relation to what our nervous systems are detecting to be very interesting. Given our discussions about differences people have in the way their nervous system interpret difference sensory inputs, it would seem that "reality" must exist even though it is different for everyone. I happen to be one of the very few females that are colorblind, like most other colorblind people, I didn't know something was different. My reality is different from someone with color; yet, I can still function in the same environment – with some variation. With everyone's nervous system interpreting things differently, is there a common "foundation/thread" that allows us to function and interact one with another despite our differences? If there is such a "foundation" is it in any form rooted in our nervous system? Is there a point where differences are too great to allow us interaction with each other – are those differences possibly rooted in the nervous system? If so, are they in the I-function, or non-I function part of the nervous system?
Name:  Ariel
Username:  asinger@brynmawr.edu
Subject:  
Date:  2004-04-27 00:01:08
Message Id:  9628
Comments:
I think that the concept of personal perception of color is fascinating. While I was hunting around on the internet looking for information on color versus black and white images I found a website (kolorbar.com) set up by a couple.

This couple, Susan Larsen and Patrick Collentine, take photographs, with a twist. Every time they take a photograph one of the two stands in the picture holding a six foot long kolorbar (a strip of material that contains eight colors on it, used commonly in the printing and graphic design world).

It is really fascinating, they have a number of their pictures up and it is possible to see in each picture colors that relate to the colors on the kolorbar. For me all of the colors stand out a great deal more with the kolorbar present.

I was wondering what causes the colors to become more defined and brilliant in my mind when I see them next to a sample of a similar solid color? If there was no kolorbar I would not have noticed that the blues or greens or whatever are such specific colors, I would see them as a whole picture. I just thought that this was a really cool idea.


Name:  prachi dave
Username:  pdave@brynmawr.edu
Subject:  colour
Date:  2004-04-27 03:10:58
Message Id:  9629
Comments:
what i'm interested in is the representation of colour in the mind insofar as we seem to know the "right" quality of texture of colour as it exists in the real world even if the object we are referring to is not present at the time. when i paint, for example, i know when a colour is absolutely or subtly wrong and colour in turn is attached to other various details which enrich it and allow it to become "real". so there's another question, when is colour just a colour rather than the various features attached to the colour? for example, colours can have affective associations, cultural associations, physical associations etc.
Name:  Chelsea
Username:  clphilli@brynmawr.edu
Subject:  Chromatic Language
Date:  2004-04-27 03:56:47
Message Id:  9630
Comments:
This is in response to Erica's comment/question about the "learnedness" of color. I was reading (for another class) Linda Woodbridge's article "Black and White and Red all Over," which references and explores a series of studies done on the development of color language within a culture. The article is about 50 pages long, with only the first 15 being in any way academically relevant; BUT, the important point is a list- IN ORDER- of colors developed by any given culture.

The first color words to develop will always be black and white. If a third is developed, it will be red. The fourth and fifth will be yellow and green; the sixth will be blue; seventh brown; eighth, ninth and tenth: pink, orange, gray. Strangly, purple doesn't make an appearance in this particular set. A culture's color language also seems to be indicative of its cultural complexity. So, as a culture becomes more complex, it begins to develop language involving the description of shorter wavelengthed photons. As a culture evolves, is color language evolves and is found useful enough to be taught to the next generation.


Name:  Michelle
Username:  msamuel@brynmawr.edu
Subject:  Perception and Color Blindness
Date:  2004-04-27 04:15:15
Message Id:  9631
Comments:
A few weeks ago, we discussed our brain "filling in" what our blind spots could not see. We examined the various ways that the brain reacted to given experiments. With this in mind, could we possibly apply this to color blindness? After reading several postings concerning color blindness, I began to wonder whether those who were color blind could dream in color. Through a quick web search I found that color could be perceived in dreams. Visual and auditory sensations are essential to the waking state. They also play a key role in producing dreams, particularly the internal excitations of the retina. Although there is a relationship that exists between the mechanisms of color perception during a waking state and the color perception during a dream state, the idea of color centers in the brain account for color perception and the sensory organs involved in dreams not being subjected to the stimuli normally encountered in color perception and its related sensory organs in the waking state. Therefore, color, a perception that is a combination of both visual and neural processing, is able to be seen in dreams. With the neural cues received during the dream state, would it be possible to have a color blind man's vision in the waking state have "fill-ins" of color? Aided with the memory of dreams, could a color blind man gain a larger limitation of colors through which he perceives the world? Could techniques be established to improve color range among the colorblind? What sort of limits on the brain's "fill ins" would then be established?
Name:  Jean
Username:  jyanolat@brynmawr.edu
Subject:  
Date:  2004-04-27 04:16:59
Message Id:  9632
Comments:
Our recent discussions on color have made me realize how very different everyone's brains are. Different brains interpret wavelengths in a variety of ways which can be of little or drastic difference. The concept of one wavelength can lead to different interpretations leads us to think about how other inputs are interpretted differently by everyone. It is fascinating to think that one input can lead to a variety of different reactions/interpretations depending on the structure and functioning of a ceratin nervous system.
Name:  Allison
Username:  abruce@brynmawr.edu
Subject:  optical illusions
Date:  2004-04-27 08:21:04
Message Id:  9637
Comments:
With phantom limb syndrome there is a disconnect between the idea the nervous system has of our physical body and the reality of our physical state. In the case of the phantom limb, the nervous system hasn't evolved to handle this lapse between perception and reality. Comparing optical illusions to the phantom limb concept, these two notions seem similar. Just as sensing a physical state seems effortless, it is difficult to appreciate the sophisticated machinery involved in sight. Do optical illusions stem from some assumption the visual system is making, in the same manner as the nervous system assumes a complete body? Are illusions those stimuli that exist at the extreme of what our system has evolved to handle?




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