Neurobiology and Behavior, Week 12

Now I think about it, I always knew that what we perceive is a construction of the brain and there is no absolute truth in the things we see (or there is, but we wouldn’t know). I knew about color blindness, illusions we experience, and that colors on objects are really the different rays of color bouncing off the surface and how we perceive. Yet, it surprises me every time I experience some illusion tests, like the blind spot test and checkerboard example, and can’t believe how unreliable my brain is. I think I expect something more than “informed guess based on presumptions” for our brains.

Since we talked about how our brains perceive color this week, I was wondering, can we tell how differently we each perceive color? One can say something is red and another can say it’s orangish-red. But maybe, their brains are perceiving the color exactly same, but their explanation of the color is different. If we ask them to choose a color on the paper that best matches the color they see, they might choose exactly same color. How can we then tell they are perceiving it differently or are they perceiving it differently at all? Unlike illusions, for example like checkerboard example, where there is absolute truth and there is way for everyone to see the “answer”, color is much complicated concept, because subtle difference in the hue or shades of the color is difficult to verbally explain.  

As we have been discussing visual perception, I am becoming more and more convinced that our interpretation of Emily Dickinson's poem is correct. However, the presumption that my experience of things is not the actual experience of things, but rather a brain construction, is still a challenging concept for me to accept.  I do not find the explanation to be wrong or insufficient in anyway, it just has raised a lot of questions for me about what actual capabilities and experiences I have, "I" meaning my I-function. I guess I can make it simple for myself and just say the I am my nervous system and nothing more. I guess I could say there is no actual mind, soul, spirit, I-function except that which my brain creates. I guess I could also be less pessimistic and say that while I am my nervous system, I at least have a nervous system that is able to construct an idea of an of me, I, and Tessa. I can look at it as if I have a highly imaginative nervous system, a nervous system "wider than the sky", that is continuously producing complex compositions of the world. However, because I also have this idea of "I" and this idea of mind and soul lurking about in my brain, I become maybe a little bit disappointed that I am all brain. Yes, I am still underwhelmed by the notion that it is all brain even though this notion in a way expands my possibilities and capabilities.  I can do so many things without even thinking about it - without even having an I-function. Without my nervous system taking precedent, there would be no color, no 3D, no visual experience. My compositions, even though they in fact are not reality, are still amazing given the fact that it takes very little effort to create them. I look outside right now. I see blue sky. I can sense that there is wind outside by the way the trees are moving. Pink cherry blossoms. Green grass. People walking around and about. In seconds, I have created a picture outside without stressing or thinking. Just observing. No felt energy expended. Knowing that I am not really seeing what is out there is quite a trip, but I guess it does not make it any less brilliant.

Another question that keeps coming to mind is why do I even need this I-function? It is kind of getting in my way...

Also, in terms of the color, we said that yellow is NOT 550nm of light but rather the activation of 2 cones. It is the result of color mixing and the relative activation of one cone to the other. We said that the color we are experiencing is NOT the result of the wavelength of light, but rather the arbitrary distribution of photo-pigments. But is it not possible that the "color mixing" or distribution occurs in a way that produces a particular wavelength, say 550nm that is perceived as yellow? If 550nm is not yellow, and if wavelengths do not actually correspond to certain colors, why are we taught this idea?  
 

            Learning the differences between the rod system and cones was very useful in understanding color. When we discussed the rod system in class, it made a lot of sense that we couldn’t see color, but only light. The same permeability changes and signals were occurring for different wavelengths of light, so the brain had no way of distinguishing these signals. I found the point about color being a construction of the brain also very interesting in class, but in particular that colors can be constructed differently in different brains. I have always assumed that my version for example green is the same for every other person, but since color is a construction of the brain, this can’t always be true. The idea that colors are a construction of the brain does make sense to me in certain situations when different people can’t agree on one color being for example purple. In this case, two different people perceive the color as two completely different colors.

It is also amusing to think about the fact that to this day there really is no exact way to describe colors specifically even though they are a part of our daily life. However, I don’t think there are concrete ways of describing a specific color anyways since we all perceive them differently.    I also found the point that colors are fully dissociable from wavelengths to be very interesting because I was always taught that a specific wavelength needed to be prevalent to see a particular color such as red. I would be interested in learning more about being able to perceive colors without having that wavelength of light available.  

            I was particularly fascinated by our discussion of color blindness this week. Like Lauren, I am curious to know more about some of the evolutionary aspects. Is there any advantage to missing certain photoreceptors? Someone mentioned in class that certain people with color blindness are more effective at detecting camouflage. I would be curious to know if there are any “natural” applications of color blindness. Also, how is this manifested in the animal kingdom? I would think that it could be a serious problem for certain wild species. On the other hand, if a certain species existed in a very colorful environment, perhaps an absence of certain photoreceptors would serve as a welcome simplification of their chaotic surroundings.

            We have discussed how our brain “fills in” lapses in sensory perception. If input is blocked (such as by the blind spot in our vision), then our brain can subconsciously plug in what is likely the appropriate missing link. This occurs without our conscious consent. This makes me wonder if our brain could fill in color in the case of color blindness. Is it possible that our brain could recognize certain shades or textures and “color it” such that we perceive color without the appropriate photoreceptors? Theoretically, if we can fill in shades and spots in our blind spot, then maybe we can fill in color as well. Is it possible that we could be color blind and not even know it because our brains are “picking up the slack” of our photoreceptors? This may be an extreme example of what the brain fills in, but it seems clear that our brain does indeed fill in small “blips.” Hence, what is the limit of what our brain could “fill in?” Could our brains be filling in more than we might expect? Maybe we’re not actually “seeing” anything but rather out brains are just filling in everything according to expectations.

            I am very interested by the mechanism through which our body fills in what we don’t actually input from the senses. What is actually going on when we complete the line in the blind spot? Like other bodily mechanisms, can it be impaired/enhanced through substances, disuse, or training?  If it is like the stitch-work that we are doing constantly with our eyes, can it be affected by damage to the nervous system or the brain? I’d be curious to look into how injury affects our ability to piece together missing sensory inputs…maybe a good web paper topic.

Well I was going to talk about vision, but then I came across this article by LiveScience which seems to shed a new light on human perception:  (http://www.livescience.com/health/shy-brain-process-information-differently-100405.html).  The study suggests that the input/output systems in shy individuals are notably different from that of the extrovert.  One really interesting part of the study found that shy/introverted people may pay closer attention to sensory input, with more activity happening in the part of the brain that sorts stimuli than everyone else; shy/introverted people are, according to the article, more sensitive to loud sounds, caffeine, crowds, and pain.  

Could shyness be so predetermined?  Does this study suggest that a lot of nature, and maybe not so much nurture, play into a person's shyness since it's very much to do with how our brains handle sensory input?  And is the shy person evolutionarily favored because of his inclination to process input more slowly before acting upon it?

I have to say that although I know that we perceive colors differently, at first I didn't want to believe colors are the construction of the brain. I used to think the wavelengths of the photons are the "physical basis" of colors, and our different perception of them is due to the limitation of our body structure. Our last class completely changed my vision. Now I do see the point, and it actually helps me understand the chromatics better. It's fascinating that our eyes can distinguish so many colors.  I do graphic design with computer sometimes, and I know there is a big difference between the color spaces on computer and in print - and the range of colors we can see is much wider than both systems'. People in the color space business are constantly expanding the color space by finding ways to show the colors we have never produced.

I also find the discussion about binocular stereopsis very interesting. My right eye has been shortsighted for a long time, but since my left eye is normal, I don't wear glasses. So I'm actually looking at things with one eye. Somtimes it does affect my sense of space (for example, I can't play badminton because I can't tell the distance very accurately), but for most of the time I'm doing fine. I wonder what the other ways we have to sense the depth. Also, what is the role of our experience in this? 

 First off, I just want to say that I love color, it fascinates me. Color vision is something beautiful we often take for granted. I understand how we all have different perceptions of each and every color (from crayon colors cerulean to macaroni-and-cheese), but it is hard for me to believe that people's color concepts vary SO MUCH. For example, I find it hard to believe that someone (who has no form of color blindness)'s "orange" could be my "green" because both of us describe "orange" to be "warm". However, it fascinates me to imagine what someone who is color blind sees as a color they are not capable of seeing. For instance, if they are missing their high range wavelength cones, do they notice a difference when someone else calls something red, and another calls something green? In Little Miss Sunshine, the brother wants to be in the Air Force, which you can't join if you are colorblind. He does not realize he is colorblind until some point on their road trip, which is several years into his life. What did he see?

Another thing that really fascinates me is electronic color. How can you program a computer, a tv, to produce a specific wavelength of light? One often thinks of color (the reflection/absorption of wavelengths) as an intrinsic property of an object...how are those lights created and how can they change?

I really enjoyed discussing vision this week in class, as it's something that we all take for granted without truly understanding it. The most interesting aspect of vision that we touched upon this week for me was the topic of color. It's interesting that color is not a physical property of the world, but instead a construction of the brain. This idea has plenty of examples that help support its statement. Dogs don't see in color, but humans do. Therefore, there must be some physical difference between dogs and humans in the brain that allows only us to see color. Also, in a dark room, it is impossible to distinguish different colors because no there is no light to reflect off the objects. This is a counterintuitive idea, but an easy one to understand because of the many examples in everyday life. We talked in class about how we only see color if our cone system is activated. I remember doing an experiment in high school biology in which an object was put in an observer's periphery vision, and the observer stated whether he saw the color first or the shape of the object first. I don't remember the outcome of the experiment, but either outcome would suggest that cones are more densely compacted in one area of the eye and rods in another. Is there some sort of evolutionary advantage to this? I found it truly interesting that we analyzed how we 'see' color, and I look forward to analyzing other senses.

 Talking about the eye I felt frustrated, I understand the eye, I understand it is important that we get a lot of sensory input from the eye. When talking about the eye I wanted to connect what we had learned so far about corollary discharge and central pattern generators, refractory loops, etc. to understand how the signals from the eye were used with the other parts of the brain. As we kept talking about the brain making a picture, making deductions, is this because of corollary discharge or is it more through the I-function? How do central pattern generators fit into the information we have discussed about the eye? I figure we would have a CPG for blinking, but what else? Could you have a CPG for colors and the names that go with the color you see? I know that when a person asks about what colors I'm seeing I use the words that were told to me by my parents and teachers. Then when I was able to read I would look at the crayons and read what color the crayon was. Did I form a CPG or amount of neurons that I use day to day to figure what colors I am seeing, or was the CPG always in my brain that recognizes the signals from colors and I just added on names. Does this even make sense? Is it right? I know that behavior can be greatly influenced by the eye, by the sensory input, like when I see an object flying at my face I will try to protect my face by lifting my arm. There is a connection between the eye and a CPG of movement of my arm. I feel that I am ready to explore more of these connections with what we first discussed and how to connect what we discussed about the eye to then figure out behavior. I'm ready.

 This week we started talking about color and how the way we perceive colors is all a construction of the brain.  This made me think of the countless number of times I have argued with my friends and family over the certain hue of a particular object.  So an object that I perceived as teal, so more of a blue-green, was just plain green to someone else.  I always thought the way I perceived the color was correct and didn't understand why we all saw colors differently.  Now I understand that our brains all perceive color differently and the "maximum" peaks in our photoreceptors may shift slightly from person to person.  Therefore, my brain may discriminate between more heavily between two colors than someone else's brain.  I know now that the color argument is not worth pursuing because we all have different views of colors and that should be appreciated rather than fought over.  It is interesting that something like color is a construction of the brain just like how opinions and ideas are a construction of the brain and they all vary from person to person.