Serendip is an independent site partnering with faculty at multiple colleges and universities around the world. Happy exploring!

Neurobiology and Behavior, Week 11

Paul Grobstein's picture

Welcome to the on-line forum associated with the Biology 202 at Bryn Mawr College. Its a way to keep conversations going between course meetings, and to do so in a way that makes our conversations available to other who may in turn have interesting thoughts to contribute to them. Leave whatever thoughts in progress you think might be useful to others, see what other people are thinking, and add thoughts that that in turn generates in you.

As always, you're free to write about whatever thoughts you add this week. But if you need something to get you started ... 

Science, as we have defined it, is a summary of observations constantly informing itself through new observations. What does it mean that these observations are subjective? What if a variety of constructions can fill one blind spot? Which one is correct? It seems that developments in neurobiology may be problematic to science as something sterile and calculable ... drichard

Is it so that all "observations" are subjective? that there are always "blind spots" that can be filled in in a variety of ways? What would be the implications of this for science? for life? What new questions about the brain would follow from it?
OrganizedKhaos's picture

photographic memory

The house simulation was intriguinng and left a lot of questions. I am one who often likes to consider myself as one with a photographic memory. This is where it seems to become tricky. When taking an exam or remmebering things I often see the page of notes and the words that are present etc. I cant see the position and all. But in a sense I do not see myself as having a photographic memory because of the I-function. Can it be that it is filling in blanks and making a likely story? I am often very accurate in my delivery of information but often is not always. I would like to do more research about photographic memory and what qualifies one to identify as an individual with this aspect.

I also find that the house simulation could have been done a number of ways without photographic memory capabilities, but is that possible outside a sense of direction? maybe I being optimistic?

ilja's picture

Our brain is a distributive

Our brain is a distributive system. It does not have one picture or one essence that determines our functioning. It is a large system of connections and cooperation in which all parts are important but in which not one is ‘vital’ in the sense that there is not one specific structure that contains our identity. Learning this was not difficult because I did not understand it or did not appreciate its positive effects. The reason why it is so hard to understand it is because from my day to day life I DO see one picture. I DO experience myself as a singular essence, ‘a me’ who is there in a reality that accepts what is out there to be the truth. So now my question is: where does this sense come from? We have a structure that actually works pretty well so why not experience it that way? I can’t really imagine what this would be like but why do we create the experience of one picture if it is not there? Where does this sense come from and why does it overrule the actual input from the different systems that we get?  The I-function seems to miss a lot and not to have a physical place in the brain, so then why is it the only way in which I can think about myself?

bbaum's picture

I don’t necessarily agree

I don’t necessarily agree with the notion that only humans,who are fully self-aware, are the only organisms that could have completed thetask in the house simulation. I think that humans have developed the neocortexbecause they lack other senses and processes that other organisms have. Forinstance, a dog, who doesn’t have a fully developed neocortex, could haveeasily found its way out of the house because of smell and certain types ofbugs could have found their way out because of community relationships (ie. antcolonies). Humans don’t possess the extraordinary skills that some of theseanimals use, so they have had to develop other ways to get themselves out oftricky circumstances. If, along the course of human evolution, we developed asense of smell akin to dogs, do you think the neocortex would still havedeveloped? Or is it possible that being self-aware is simple another “specialskill” that humans have because of an evolutionary fluke? If humans onlydeveloped a neocortex to compensate for failures in other areas of the nervoussystem, our seemingly amazing skills are not so amazing. I think it’s humannature to look at a dog sniffing the air for a squirrel and attribute thisskill to the animal’s nature, but look at our own skills and see something thatis out of the ordinary, something that is way beyond anything that any other organism could possibly do. The neocortex allowshumans to complete certain specialized activities, just as the dog’s noseallows the animal to sniff an animal from across a field.


Leah Bonnell's picture

Benefits of Ambiguity

In class we discussed visual ambiguity and how ambiguity is never eliminated. It briefly came up that ambiguity is connected to the "crack" in understanding, referring to the loopy science model we established earlier in the semester. The crack is what allows us the see from a new perspective in order to create a new summary of observations. Visual ambiguity can provide this new perspective; if we see something differently we can create new observations. 

From what we learnt in Week 12, I would say mood is also a source of visual ambiguity and mood fluctuation is a reason why ambiguity is never eliminated. 


nafisam's picture

More Color

I found the question of whether color is an aspect of physical reality or just made up by the nervous system to be really interesting. Although color is a function of the overlap of different wavelengths, it does seem as though it is a physical reality. When we open our eyes, we generally see the same colors as we saw yesterday, without too much deviation. Colors are just like edges when helping us to define different aspects of our world.
eglaser's picture

Seeing color in white

One of the questions that this class sparked in my mind is one that I have heard before, if we all see things differently, how do we know that what one person thinks is red is the same as what another person thinks is red? Is there any way to have a standard in terms of color? Or to determine that what we see is the same?

One of my friends is a fine arts major who is currently taking a painting class, one day she said to me, "I don't see white anymore, when I look at a wall it is never just white. Everything is full of color." When I look at a white wall, I see a white wall. We both look at the same object and see different colors, a perfect example of the subjectivity of sight and how the brain processes input. Is her ability to see color in white because she has more sensitive cones in her eye, or has she just trained herself to see it because of her painting class?

jwiltsee's picture

Yesterday I read an article

Yesterday I read an article in the paper about a legally blind man who is a so called "wizard" as a hitting coach for baseball.  The man said that he is able to see his pupils swing out of the corner of his eye.  And out of the corner of his eye he said he is able to just see a triangle between the hitters chin, the end of the bat, and the players elbow/torso.  He then said he is able to fill in the rest of the image and he even went on to say he is able to see what will happen next in the swing. 

This got me thinking about the conversation on edges and how we fill in the pictures.  One of the interesting things in the article was that there were many people who believed his hitting instruction was nonsense because he was blind.  On the other hand he was contracted by pro-baseball teams, sent 30+ players to D1 schools, and coaches many youngsters.  It seems that a man who has been legally blind for 35 years is able to create the correct image in his brain more times than not.  This may be from the fact that putting images together in the brain is not only a function of seeing, but the man may use his other senses to piece together the swing.  Maybe since his eyesight is week, the inputs from his other senses are stronger?

redmink's picture

thank science

The role of science is to provide us with a firm ground on which we can actually stand together.  We, coming from a different background and having a different brain from each other's, have different opinions and view of the world.  But if we did not enroll this class, or learned about objective theories taught in science courses, we would not know how our brains construct different worlds and how the truth of each individuals varies. 

Indeed, I think science with its certain objectivity bind us together and put us in the situation where we feel that we need to share our own stories and make new observations to add onto the pre-existing human knowledge.  Just like the Bible, i think sciecne is one example of good textbook that we all look at and make argument for/against.

Anna Dela Cruz's picture

Schizophrenia and Optical Illusions

"We don't see with our eyes, we see with our minds"

At the time I heard this in class, I was intrigued by the implications--that perhaps reality as we know it/perceive it is subjective if we are operating under the idea that no two brains, and therefore, no two minds are the same. I then came across an article from Medical News Today (link provided below) that disturbed me. The article, Hollow Mask Illusion Fails To Fool Schizophrenia Patients, concerned a joint British and German study on the effects of optical illusions on patients diagnosed with Schizophrenia. With the "hollow mask illusion" (youtube link provided) as a test example, both control (non-Schizophrenic) and experimental groups were shown a series of images containing hollow (mask) and normal faces while inside an fMRI machine. The aim of the subjects was to distinguish between which images were of the hollow, concave insides of masks and which were normal, convex faces. As expected a staggering divide was established: all 16 control subjects percieved the hollow mask as normal faces (99% error rate) while all 13 of the experimental group better identified which faces were of hollow masks with only a 6 error rate. As mentioned in the article, Schizophrenia has been attributed to the disconnectivity between the parietal cortex, reponsible for spatial perception (a top-down control) and the lateral occipital cortex, responsible for processing visual information (a bottom-up control). This was evidenced by the fMRI scans of the experimental group. If the aformentioned two regions of the brain are not talking to each other yet these patients are unfooled by optical illusions while non-Schizophrenic people are duped, what does this say about our realities? In the way we percieve the world, is it that our brains are playing tricks on us? And far more disturbing, do Schizophrenic patients see more of the truth than we, non-Schizophrenic people do?

Hollow Mask Illusion Fails To Fool Schizophrenia Patients

Hollow Mask Illusion


bbaum's picture

In chemistry we are taught

In chemistry we are taught that colors are created bydifferent wavelengths of light hitting the retina. The different colors arecreated by excited electrons releasing energy as they fall to lower energystages. I never thought that there was any difference between the way in lightin produced and the way in which the human perceives color. When I look at arainbow it seems impossible that a very limited types of cones are actuallyinterpreting all the colors that I perceive. This concept is akin to the brainactually seeing all objects as the boundaries of edges.


Again, I was also surprised by how much the brain just“makes up” as it goes. The fact that humans have two eyes is veryevolutionarily favorable because it allows humans to have better depth perceptionand a better range of vision. But, on the other hand, the fact that we have twoeyes means that the brain has two conflicting views of the world every secondof the day. Because of the conflicting views that the two eyes present, we haveto make a view of the world that is the “best” compromise. The most frustratingpart of this is that we will never know what reality really looks like.


I’m also interested in what makes certain colors moreappealing to people. For instance, I’ve heard that American’s prefer the colorblue. Is color favoritism simply a cultural phenomenon? (the colors of the USAare red, white, & blue) Or is there a neurobiological component to this? 

Max86's picture


i've been preoccupied with the concepts of lateral inhibition and corollary discharge lately. My concern: How does understanding these terms in a neurobiological sense shed light onto seemingly analogous, broader socioloical issues.

Lateral inhibition and the checkerboard seem to imply that our vision and the way we conceive of others is based off of a primal, edge-biased mode of perception.

as a means of distinguishing between self-generated and external stimuli,  Corollary discharge seems relevant to meditations on time and memory in art and philosophy. For example, Hollis Frampton's film, "Nostolgia,"demonstrates the impossibility of pure recall. Any time one recalls the past, one must simultaneously be of his present. Memory seems to function as a corollary discharge mechanism that must attempt to salvage data while futilely asserting that data as distinct from the perceptual realm of the present. With all its all its concomitant stimuli, the present is always already slipping away itself as memory just as another memory was called to mind. 

Sam Beebout's picture

dreaming in color

On Friday my alarm went off early because I forgot to reset it. When I woke and walked across the room to turn it off I remembered our discussion about seeing color. If I didn't think too hard about it, I realized that I wasn't really seeing color. I looked at my pink bedspread and though about how it shouldn't look pink. I was making it that way because I knew it was. 

I don't think it matters whether I am really seeing it a certain way or whether I am remembering it. Even though there is a difference for my eyes, my mind makes it so. I'm not sure whether I dream in color or not, I can't be sure. Supposing that I do dream in color, where is that color coming from. How do we remember what we perceive?

It seems like what we perceive must be heavily linked to what we remember. It is practically impossible to feel like I'm seeing something for the first time. How does our brain know when it is seeing something for the first time? 

Are we seeing differently all the time or are we always seeing what we expect to see? Are we made to ignore subtle differences?  We are so programmed to construct cohesive images in our mind. While memory would seem to operate like a photograph, what we have discussed about the brain's constructions so far makes the mind more of a storyteller. Our perceptions are easily fooled and easily adaptable, so much so that it becomes hard to notice differences in what we perceive against our expectations and assumptions.

ddl's picture

Perceiving Colors

I too have always wondered about the idea of color perception varying between different individuals.  The idea that one person could describe a certain color that they associate with the term red as “red” while another could perceive a totally different color as their “red” is not that farfetched to me.   Since a given individual has routinely, since their first experience of a particular color, associated their perception of that color with a given descriptive term, what is to say that these constructions have to be consistent for each and every individual?  Due to the uniqueness of a person’s nervous system connections and the layout/productivity of their photoreceptors and other light sensing components, why would be a stretch to think that different individuals inherently perceive the color spectrum in different ways?
drichard's picture


It is interesting to think about certain visual art forms (like painting) in terms of our conversations concerning the perception of colour. If colour perception is a function of light, then the painter, in a sense, becomes (among other things) a manipulator of wavelengths. Does this idea edify our consumption of art?

Differing aesthetic judgments about art could be accounted for by the fact that people percieve colours differently, especially when it comes to relationships between colours.


Also, this week got me thinking (once again) about how individual our experiences of reality truly are. We discussed how head position, eye position, object position, distance from object, and whether or not one eye is closed affect how and object is percieved. In this way it is highly unlikely, if not entirely impossible that two people will ever see the same exact thing upon looking at the same object.

Adam Zakheim's picture

week 11

 In class, we discussed the idea that what we see is not "reality" but a "story", an informed guess about what is out there. If the brain is capable of making these types of visual estimates, does this mean that psychics can really predict the future? Fundamentally, it takes time for our visual cortex to process and interpret information from visible light reaching the eye in order to build a picture that we “see.”             Our visual perception starts when the lens of the eye focuses an image of its surroundings onto the retina. The retina, via the foveal structure, serves to convert patterns of light into neuronal signals which are then carried, via the optic nerve, to different parts of the brain, including the  lateral geniculate nucleus, to the primary and secondary visual cortex of the brain.            It was interesting to learn that evolution has endowed our brains with a slight degree of prognostic capability. Given the complexities of visual perception as well as the constant bombardment of light on our eyes, it makes sense that the brain would try to create a picture of what one “needs” (i.e. a picture of what something will be when one needs it). This mode of perception relies on one’s past experiences to construct the necessary picture. This instinctual quality with in the visual cortex of the brain constantly tries to predict the future.        This brings me to psychics. Out of cynicism and skeptikism, I have never believed psychics could actually predict the future. We have shown, however, that our brains have the ability to contruct and fill in the gaps with in our visual perception and also predict the future to some degree. So, is it possible that someone might have an over-active visual cortex, which nature has endowed with the ability to “acurately” contruct future events?
Bo-Rin Kim's picture

The idea that colors are

The idea that colors are made up by the brain is indeed an interesting concept. This idea has always fascinated from when I first learned about color blindness in 7th grade. If colors are made up in the mind, does this mean that everyone can potentially have a different idea of what "red" or any other color looks like? Could I perceive a certain light intensity differently than someone else but we would still be calling it the same color of "red"?

Also, the idea of color being constructed in the mind can also be confirmed by what we know of synaesthesia. People with color-grapheme synaesthesia see colors that are not physically present when they see a certain letter/grapheme that does not appeared to be colored to non-synaesthetics. Thus, this shows that the mind is fully capable of creating colors that appear to be of the physical world. 

aybala50's picture


The idea that colors are a construction of the brain makes a lot of sense to me. In high school I remember one of my science teachers had said to us 'it's possible that everyone sees colors a little different from each other'. It does seem possible that since everyone has an individual brain that we can see colors differently. 

Also on the thought that different colors can produce different does that work? Is it all about what colors are associated with in culture? Such as black and death?  

ilja's picture


What we see is not what is out there. We saw some examples of the brain making different guesses of what could be out there. What interests me is how the brain can combine guesses and information from different structures to create new ways of seeing. I find it amazing that by having two eyes that create different images the brain simply concluded that thus there should be dept and looks for information to support that guess in other senses as well as monocular evidence. When talking about these observations that the brain makes and how it uses them in comparison to each other I also think that learning is an important factor. When I was small I could never see the images hidden in the stereogram. It would drive me crazy; I would stare at the book for hours trying to see the hidden images. When I look at a stereogram today I do however see the images appear. It takes me some time and effort but in the end I can see the images coming out to me. It is as if you look into a different world or dimension that was not there before. Learning and practice thus do seem to have an impact in creating new guesses that the brain can make.  

jlustick's picture

Seeing as Revealing

We learned this week that what we see is not the only image out there, but one of many guesses that the brain has. I am interested in the way that the brain decides which image is the best guess. Why was it that some of us saw a scull while others saw a woman in a mirror? How much does what we see reveal about who we are? According to proponents of the Rorschach inkblot tests, image identification is quite psychologically significant- what we see says much about the "demons" lurking within our unconscious. So are those who saw a scull more morbid or plagued by fear of death? Are those who saw a woman in a mirror obsessed with appearance and beauty? Or is that going too far? Why are the Rorschach tests more revealing than our interpretations of our ever-day world? To what degree can a person be blind to certain aspects of the world and how can such blindness be overcome when it proves problematic? In other words, is seeing a learned behavior rather than a simple input, and can it be re-learned? Does a person undergoing psychological treatment, whether therapeutic or medical, exhibit a change in vision?
Sarah Tabi's picture

What if all observations were subjective?

I admit there are some scientific observations that are subjective.  Yet, the advances that had been made in science are done with the assumption that they are rooted from objective principles.  For example, an observation made that a particular chemical is highly colored is based on the fact that the chemical compound that comprises it is conjugated.  If all scientific observations were assumed to be subjective, then "facts" would cease to exist.  Scientific theories would all simply be suggestions.  There would be no concept of a "right" or "wrong" answer.
Lisa B.'s picture

Week 11

The subjectivity associated with relations of power shape our lives.  Although there are blind spots, social rules determine how they are filled. For example, Bryn Mawr would not be an elite academic institution if it had no standards of evaluation. Although grades are often a distraction to learning they provide important admissions criteria for graduate school, law school and medical school admissions committees. If an applicant and application reviewer do not share similar social configurations, in this case the subjectivities of education, then the qualification of a student may be difficult to determine. It would be interesting to explore if numerical evaluation required in our educational system changes brain chemistry? Maybe our physiology is regulated by the social behavior required to succeed in an environment of criticism?  
hlee01's picture

colors and the brain

I thought it was really interesting how we only have three cones that allow us to see infinite number of colors. My question is then what happens when you only have two cones or just one? My guess would be that you would be able to see only limited number of colors. Another question is how color blindness works? Also, are there people who cannot see yellow but see two separate colors instead?


Brie Stark's picture

When we discussed the

When we discussed the optical illusions -- for example, the skull that could also be seen as a woman with a mirror (but was, in reality, just light and dark) -- I was intrigued by the fact that each of us perceived the image differently, and also perceived the changing of the image differently.  I personally saw the skull first and could not see the woman until it was pointed out.  As soon as it had been pointed out, however, I could unconsciously switch between seeing the two images.  This lead me to think: is this how social norms/ideals are contradictory?  Society seems to have a conception that we must all conform to a specific ideal -- example, skinny in terms of body weight -- and yet, with this simple optical illusion example, we see that everyone perceives the world differently.  Therefore, a "social norm" or an "ideal" can't possibly exist; each person perceives their surroundings because of their beliefs, expectations or experiences.  There isn't "one way to see it," because constructs (as we discussed) depend upon the aforementioned things, like experience.  Following this line of thought, if everyone perceives the world differently, there doesn't seem to be a clear-cut line between "right and wrong" or "incorrect or ideal" or even "disabled or able-bodied."

Percival52's picture

More similar then Differrent

I think what i have learned from our discussion about vision is that we are more similar then different. As we saw the optical illusions, almost everybody could see the different images (skull and the lady, the flashing lights going one way and then the other) but no one saw some crazy third option. I think when given two equally valid options the brain's subjectivity is a huge factor, but for the majority of life this is not the case. We tend to see things in absolute terms, and when a situation is ethically murky, we wish we could see it in absolute terms. If our brains weren't similar enough to interpret the same data in a highly correlated manner then as a species we would have never agreed upon anything. It is important to have an orginal point of view but it is better to be able to agree on things.

On a less related note, I was wondering if it is possible to see time. We understand that what we are seeing is always delayed because of the time it takes for light to reach our eyes, but just how aware we are of this effect is unclear to me. There have been times when I have seen something far away, flinched and then looked again only to see that what i thought was going to instantly harm me, hasn't even reached me yet. i certainly flinched out of anitcipation but as that ecperience happens more often, i begin to flinch less. Does this mean i can see time better? Maybe if we had some other optical molecule like cylinders or pyramids to go with our rods and cones, we might be able to better percieve time.

Crystal Leonard's picture

constructions of senses

The discussion today about color reminded me of a physics lab I did a few weeks ago involving light waves and vision. In the lab my partner and I proved to ourselves that most of the colors that we see in the world do not actually correspond to specific light waves and are fully constructions of our brains. For example there are no wavelengths of light that correspond to magenta, brown, etc. Yet it is still incredible to me that with only 3 types of cones ("red", "green", and "blue" cones) the brain is able to create an infinite number of colors, shades, and hues. I know that every single possible ratio of absorbtions for these cones will cause a separate constructed color, and if I actually did a statistical analysis of all the possible permutations I would find that it does indeed make sense. But it is still amazing and a great example of the creative power of the brain. Also, because color is such a fundamental part of life, and we have a very difficult time grasping that no those leaves aren't truly green, it makes me wonder what other "truths" we are taking for granted. I'm most interested about this idea in the context of touch. Touch has always been my favorite sense, one because in my opinion it can lead to the greatest amount of enjoyment and pleasure, and two because it has always seemed like the most reliable and "true" of the senses. However, I assume that the brain can construct the sensation of touch just as easily as it can construct vision. The question is then how it would do that, how often it does, and why. Are the things that we "feel" real?
jrlewis's picture

touch as a construction...

When my father was taking a drug called sinemet for Parkinson's Disease, he hallucinated? (is that the right word here?) the feeling of a light material resting on top of his clothing.  It distracted him during conversations and meals.  Actually, it drove him crazy; he spent hours picking the imaginary material off himself.  His doctor commented that this was a common side effect of the medication.  He had seen and heard of other patients experiencing the same thing.  I’m not sure whether his symptoms were caused by the medication or the disease.  The main medication prescribed for Parkinson’s disease is sinemet, a combination of levodopa and carbidopa that is converted into dopamine in the human brain.  Dopamine is a neurotransmitter.  Excess amounts of dopamine in the brain cause all sorts of interesting symptoms.  So maybe there is a chemical explanation for hallucinating touch? 

Articles that complicate the sense of touch in interesting ways:


BeccaB-C's picture

Mental Images

Today, we briefly touched on mental images and what mechanism allows them to be seen/by what process are they seen, and whether they are seen in the same sense that what we physically percieve with our retinas is seen. This lead me to wonder about people with varying types of blindness, and their ability to "see" mental images. I would imagine, as I think we discussed, that someone who has blindness caused by some damage to the eye, retina, or early stage of the geniculo-striate pathway would still be able to "see" mental images, as their brains still maintain  the capacity to formulate perception, with images as the output derived from thought as the input. People with cortical blindness, however, or any type of blindness that affects V1 (the primary visual cortex), might not have the capacity to formulate mental images, as the part of the brain that allows for conscious perception and creation of visual images has been damaged.

Does the process by which mental images are formulated reside solely in the primary visual cortex or is there some element of this process residing in the tectopulvinar pathway, or another part of the visual system that might be able to supplement a damaged V1?