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Nervous system architecture: from the input side
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. You're welcome to post here any thoughts that have arisen during the course this week (and to respond to thoughts others have posted)
Among the issues that have come up this week is the affect that imaging has on our conception of "reality" and explorations of retinal structure suggesting that we did indeed see things both without input, and without intending to.
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A Random Walk
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back to daydreaming
What's there and not there?
Sleep Walking
When I was young, I used to sleep walk from my room to my parent's room which was quite far down the hallway. My parents used to tell me that I had my eyes open and would engage in long conversations. However, I have absolutely no recollection of these events. Is this because I wasn't using my "I" function? Also, I was wondering how I was able to walk safely from point A to point B (the hallway twisted). Were my eyes "seeing" objects and transmitting the message to my brain which told my legs to move in another direction? Was it due instead to "muscle memory?" Because I had walked on this path before, did my body recognize which way to move?
The Ghost in the Machine
I came across this article while reseraching for my 3rd webpaper, I found it to be a good summary of our studies and also asks some interesting questions. Take a look if you want!
Anne
http://www.nimr.mrc.ac.uk/millhillessays/1998/consciousness.htm
Reading
I don't know if this happens to everyone when they read a novel, but when I'm reading, sometimes I can't tell the difference between reading and imagining what is going on in the book. I have this "mental" image of what is happening as I read, but at the same time the images are clear and I "see" what is happening as if watching a movie inside my head. When we watch a movie, say "Harry Potter" some people may say "it's not as good as the book". But why can we say this if we're comparing text with images? I think it is because of the way we interpret the text into images in our brain that allow us to compare how we thought the book should be perceived in our mind to what it is like on a screen.
Maybe "reading" is similar to "daydreaming"? In both situations you have your eyes open yet you are less focused on what you are actually seeing, and more focused on another environment.
Puzzle
After reading some posts, I agree with Emily's comment about the brain being able to compensate for what "reality lacks or our senses lack in picking up. I see this as almost a large puzzle with the conscious contributing a majority of the pieces, but the subconscious contributing the critical ones, for example like when doing a puzzle of a sunset over the ocean, I imagine that the subconscious finds the pieces of water that are ususally just lost until the end of the puzzle. This is not to say to undermine the conscious mind because without the conscious, I do not think that the subconscious could be capable of everything I am currently crediting it with because in the same puzzle metaphor, without the conscious perceiving the picture and the sizes of the pieces, the subconscious would not be able to contribute its key portions.
No answers, many questions
Angel brought up the mind-body medicine philosophy, which makes even more sense in the context of the inextricable link between mind and body we have been discussing in class. If sight, pain, etc. are an interplay between mind and body, are the limits we experience self-imposed limits? Do hope and optimism as states of mind change our perceptions? Do we “see” the world through a pre-determined (genetic) set of lenses or do we have the “power” to shape our perceptions by involving our I-function consciously?
In terms of dreaming, how is that, at times, we are able to wake ourselves from dreams? Sometimes dreaming is like watching a movie of one’s own life and when there is a scary or dissatisfying part, one can get up and leave the theater (or in this case wake oneself up). Is there a way to involve the I-function more? Would that make us more or less aware? Dreams, also, at times, are cryptic and full of symbolism and fragments of our unconscious intertwined, if we were more attuned to our dreams, would our perceptions be enhanced, or does the I-function have no role in the unconscious?
Dreaming and Seeing
While I like the discussion about day-dreamiing and not really "seeing" while we're distracted, I really think a good example of how the nervous system contructs "seeing" is dreaming.
When you go to sleep, your brain calms down and fires in a synchornous pattern for most of the night. However, every few hours, yours eyes began to dart back and forth and your brain appears neorologically awake "The dreaming brain employs all of the same systems and networks [as the waking brain]... but with a few differences. Input from the outside world is screened out. Selfawareness ceases. The body is paralyzed. And everything that the dreaming brain sees, hears or feels is generated from within." (1)
But how can you be "seeing" so much with your eyes closed?
Just before REM sleep, neurons in the pons begin to wake up and fire for no apparent reason, sending this information to the geniculate cortex and on to the occipital lobe, forming what is called a "PGO" wave or spike. This random information is, in turn, processed by the occipital lobe any way it can presumably leading to the bizarre, incoherent imagery of dreams. So your brain is actually quite capable of "seeing" with your eyes closed - of seeing even with no discernable input at all.
PS. PGO spikes released during "daytime" hours might be a neurological correlate of LSD-based hallucinations (2).
1. http://query.nytimes.com/gst/fullpage.html?res=9E05E7DD123FF931A25754C0A962958260&sec=&spon=&pagewanted=print
2.
http://www.erowid.org/references/refs_view.php?ID=3116
Seeing is believing…
First of all, Im really glad no one used that catchy title before I got to! Second, I’ll get to my actual point. Although I was unaware of the “faking” that our nervous system pulls in order to allow us to not see “holes” (whatever those might look like), I don’t think this means that the nervous system is tricking us or is misrepresenting “reality”. What is reality anyway? And does it have to equate with what is “real”? I think we established the fact that because our senses only sense so much, what our brain translates that into is only a proportion of what is “reality” outside of our senses. It seems that “real” is what we make of it, and reality is something we just simply don’t have access to. While this is all really interesting and sort of creepy, I’m not sure I see the relevance to consciousness. A few people mentioned daydreaming, imaginary friends, etcetc, all these things we see, or imagine, when we want to. Similar fill-in-the-blank studies have shown that our brains will use contextual situations in order to help our cognition so we don’t overload on trying to figure out everything for what it truly is. This seems vague, but that’s only because I can’t recall the actual studies. I learned about them in Memory & Cognition with Professor Boltz at Haverford. What I can remember, though, from that class is pretty much a whole semester of mind tricks where the brain “makes things up” so you don’t have to. For example, if a sound is deleted from a word, and the participant hears “I slammed on my b__akes”, the brain won’t even realize that the R was deleted from the recording because it fills it in for you. So this brain trickery occurs in lots of different domains of function. Again, I’m not sure the relevance of this to our consciousness debate. This seems like something that is a constructive adaptation of our brains, and it occurs without our I-function being aware of it.
Another train of thought I had during class on Tuesday was the idea of borders and edges, and I don’t know who else has seen the move I Heart Huckabees but there is a really great quote that is somewhat relevant and just kinda cool to think about: “If you look close enough you can't tell where my nose ends and space begins.” Just something to think about…is this statement true, based on what we discussed in class?Fantasy or Reality
I think Anne makes a very interesting point, we know that our nervous system limits us greatly, exactly how much we do not know. I know that it may seem silly but I have always thought that the saying 'where there is smoke there is fire' is generally pretty accurate. So many people throughout the centuries have claimed to see ghosts or spirits or other such things that the main stream population has insisted are fabrication, but what if those select few who claim to have seen such phenomena have in fact a more acute nervous system. I often times wonder where to draw the line between reality and fantasy, if in fact our nervous system are limiting what we are able to experience then what is reality? Is our perceived reality a fantasy? How much are we missing out on? Is there any way an individual can fine tune their nervous system?
I remember reading an article about a man who was very active in the martial arts, this man was able to teach himself not to feel pain. Can it be assumed therefore that pain was not reality for him, and the notion of pain was fantasy?
I also watching one of the James Bond movies where James Bond is able to lower his own heart rate past what one would consider a 'normal' spectrum can one teach their own nervous system I guess is my question?
Fantasy=Reality?
I have always believed that reality transcends what I perceive to be real. Many elements of my own upbringing have lead me to these conclusions, and while I've always been on a quest of sorts to uncover the "real" and the "delusions" in my perception of the world, I'm slowly coming to realize that it doesn't matter. Reality is simply the sum of our perceptions, real or not. Fantasy or "reality--"who's to say that one is more real/false than the other? Perhaps its all one big trick of the mind. In the end it's really all quite irrelevant. Knowing more about what "reality" really is doesn't change the fact that I still have to go class, so I can make the grades to go to grad school, get hired, and make money to support myself and a potential family. Fantasy or not, it is still very real to me. My question in a nutshell: is the pursuit of that which is true "reality" really meaningful to us? If it is, perhaps we should invest more energy in trying to understand different ways in which others understand the world from a more validating standpoint as opposed to comparing the "abnormal" to some sort of "norm."
Interesting stuff
This is a really interesting discussion...I especially liked Jackie's question about day-dreaming. Is it associated with the I-function? I'm not sure since day-dreaming often occurs unconsciously, kind of like driving or any other activity that our brains are accustomed to carrying out without our conscious effort. (which i realize now is exactly what Caitlin was driving at!) To take it a step further then, it is interesting to consider that although day-dreaming is an unconscious process, it involves the daydreamer in a very active way. We imagine ourselves in different circumstances and so on some level, we must be participating in the creation of these daydreams. I wonder if it is similar to what we talked about in class-an example of something the I-function is involved with, but does not actually control. What is the i-function good for?!
Another interesting tidbit from class has to do with the conception of reality. It seems like we were getting to the conclusion that reality is dependent on the perciever of that particular reality-if what we "see" is an amalgamation of constructions of the mind, then perhaps there is no definitive reality. And if that is the case, then what is this thing we call reality? Is it all an illusion? That then makes me think about "mind-body" medicine, and the belief that things like pain are a product of the mind and so can be overcome. If each individual percieves a different reality, then is there no qualitative thing such as pain, or emotion? That seems unlikely since we all understand the experience of both, although it is often difficult to describe to other people...
See next
invisible people
If seeing both light and image outlines depends on the refraction of light as well as a physical picture implanted on the back of our eyes on the retina, then how would an invisible person see? This consideration will seriously impede my enjoyment of stories involving invisible people since they wouldn’t be able to see. Perhaps that is why they have cartoons with eyeballs floating around. What we learned in class also really helps me to see how our processing of any input is really dependent on the physical realities of our bodies and nervous systems.
Observations: Charles Bonnet Syndrome
To respond to the connection between imaging and our conception of reality, I think we need to further explore the process of input from retina, the journey to brain, and the brain’s output of visual information. Is the brain always capable of releasing these fantasy images (that patients with CBS experience)? How do we inhibit this? Do we?
Seeing while daydreaming
One topic I have been thinking about that is semi-related to our discussion to optics and 'seeing' this week is daydreaming. I find this phenomenon really fascinating. Maybe this is not the case for everyone, but when I day dream, my eyes are opened (I am likely staring), but I am not really seeing...that is, not until I snap out of it. It is not that I perceive blackness when I daydream (that is not the case at all!), but somehow what I am 'seeing' in my daydream or thought overrides my ability to actually see (the kind that involves light sources, the retina, etc). My eyes are still gaining input from light sources and sending messages to my brain (they're open!), but when I am in my daydream, as far as I am aware, I am not perceiving what is around me.
I realize that the 'seeing' of daydreaming and the 'seeing' that is associated with the bending and perceiving of light can definitely be viewed as two different entities, but I do find it interesting that the 'fake' seeing competes with the 'real' seeing in some circumstances...or does it? Maybe I am leaping a bit too far with my assumptions...but I think to some degree the brain monitors both forms of seeing, and that sometimes there is interference between the two. Does the I-function do the daydreaming?
Daydreaming
Wow! This is so interesting-I never thought about it before, but I also daydream with my eyes open, and I definitely zone out and “see” things other than my actual surroundings. I am inclined to say that the I-function is at least participating in the daydream, although maybe not creating it. I say this because the brain is also capable of generating regular dreams, many of which we do not consciously remember. I agree that daydreams are particularly interesting in that, while we are daydreaming, we seem to be ignoring actual visual input (whereas during regular dreaming our eyes are closed and the level of input from our surroundings is minimal).
This topic reminds me of the discussion we had in class about people being able to perform habitual activities such as driving, seemingly without paying attention to what they are doing; they arrive at their destination with no memory of the actual process of getting there. I often have similar experiences when I get takeout from Haffner, and then walk back to my room in Brecon. The walk is fairly long (at least 10 minutes for me), and frequently, I will start thinking about work that I need to do for my classes, my summer plans, etc…and before I know it, I am standing in front of Brecon. Would this be considered daydreaming as well? If so, then I think there must be some part of the brain that is processing the “real” visual input from our eyes (the rest of the nervous system depends on the visual input in order to perform activities like walking or driving), as well as another portion that is generating and participating in the daydream. Before, when I thought of daydreaming, I always pictured someone sitting still, staring off into space. Now, however, I think that it is possible to daydream while performing complex activities! I wonder how the brain decides when it is ok to just go on autopilot and when the I-function needs to be engaged in the surroundings.
Vision and Reality
The seeing Tongue
"You don't see with the eyes. You see with the brain," Dr. Bach-y-Rita contends. An image, once it reaches an eye's retina, "becomes nerve pulses no different from those from the big toe," he says. To see, people rely on the brain's ability to interpret those signals correctly. All of this information makes me think how important the nervous system is and the possibility of restoring lost vision in the future.
Seeing as a function of both visual and tactile senses
Our discussion in class reminded me of a passage about sight that I read in another class in Pilgrim of Tinker Creek by Annie Dillard. She mentions and quotes from another book, Space and Sight by Marius von Senden, which describes the experience of people with cataracts, previously been blind from birth, once the cataracts was removed by an operation. She writes:
‘For the newly sighted, vision is pure sensation unencumbered by meaning: “The girl went through the experience that we all go through and forget, the moment we are born. She saw, but it did not mean anything but a lot of different kinds of brightness.” Again, “I asked the patient what he could see; he answered that he saw an extensive field of light, in which everything appeared dull, confused, and in motion. He could not distinguish objects.” Another patient saw “nothing but a confusion of forms and colors.” When a newly sighted girl saw photographs and paintings, she asked, “‘Why do they put those dark marks all over them?’ ‘Those aren’t dark marks,’ her mother explained, ‘those are shadows. That is one of the ways the eye knows that things have shape. If it were not for shadows many things would look flat.’ ‘Well, that’s how things do look,’ Joan answered. ‘Everything looks flat with dark patches.’” […] In general the newly sighted see the world as a dazzle of color-patches.’ (28-29)
I think that these observations agree well with the class explanations for the way that sight works. It now makes sense to me that one would experience color-patches or dark marks when first introduced to sight because things like distance, depth perception, and shape, have a tactile component to them. I guess the way that we learn the concept of space and distance is by putting together our visual input with our tactile input. It must be incredibly disorienting to have a concept of space based solely on the tactile component and then to have to try to integrate that with vision.What do we see?
So after class on Thursday the issue that has made me think is that our nervous system actually makes up the things that we see. I have heard this before, and have even done the blindspot test, but what is interesting to me now is that we have been trying to figure out the things that we do not see, but now it seems that there is an issue of what we do see. If our eyes are constantly working to imagine what is probabaly in or periphery, but it is not really sure, then what do we actually see?
I do not mean to get into the same conversation from Tuesday that Lindsey mentions, but for me there is a new question of reality and what we actually are seeing. I agree that there are such things as hallucinations, although now it seems harder to distinguish a hallucination from a real object. Also, what do we think a blind person would think of this discussion? Would she agree, that every human has scewed vision, or would she be angry that those of us that can "actually see" are sitting around discussion the things we perhaps, hypothetically, maybe cannot see?
Also, why do so many people need glasses?
I have to agree with Zoe's
I have to agree with Zoe's comment about hallucinations and real objects. After class on Thursday, I definitely learned a lot about "seeing" and how the nervous system plays a role. However, I am having a hard time distinguishing between real objects and hallucinations. How do we know what we see is "real" (does it have to do with the sudden brightness of pixels? does our central pattern generator play a role?) How do we know it is not simply a figment of our imagination?
Why my vision sucks!!!
Well...as some one who has relied on prescription glasses and other types of corrective lenses for the majority of her life....many people need glasses because for some reason the curvature of the eye...i.e. the curvature of our "lens" is not as "optimal" for certain distances considered normative in human vision (sometimes very small distances or very large ones). meaning that due to too little or too much lens curvature the ability to curve light appropriately so that a point light source converges fully at a photoreceptor is somehow off (i.e. the convergence of the bent light does not occur where it is supposed to) thus, images becomes increasingly blurred. Also, instances where astigmatism is present indicate a situation where an aberration or other topographical situation has arisen in which different parts of the lens and cornea focus and bend light rays differently (i.e. the curvature and focusing ability of the optical components of the eye are not necessarily uniform) creating two different areas (versus one) of sharp focus in one's vision (i.e. the eye focuses on two different points in space at once). Of course there are many other reasons why an individual may lose eye-sight some of them are congenital conditions (probably stemming from genetic makeup) while others may be influences or caused by life experience and/or environmental factors which may affect other parts of they eye. However, one of the most interesting things, for me, is how plastic eye-sight can be and how eye-sight is so quick to change at times. For instance, while I know some people with degenerative eye conditions in which they slowing lose eye-sight, I also know other people, such as my cousin, who (albeit with the help of eye-surgery) have obtained near 20-20 vision after being nearly legally blind for the majority of their childhood.
Where am "I"?
We've been referring to boxes (and boxes within boxes, and boxes within boxes within boxes...) in this class, and most of the time these boxes have proved to be actual physical boxes in the brain. (For a very loose interpretation of the term 'box') But is the I-function or the subconscious the sort of phenomena which a manifestation within a physical box? If we want to say that we are brains (the way Emily Dickinson has) then it seems like we should be able to locate "I" or even the "unconscious I" the same way we can locate the pituitary gland, but I don't feel like the I-function is a spatially extended phenomenon. I know we've been playing around with the term 'emergent phenomena', but I guess I'd like to look further into what that really means.
The "I" out of the box...
Maybe the "I-function", like long term memory, is not confined to a single, particular box or group of connected neurons but is spread-out in bits in pieces throughout the brain...in a sort of matrix of boxes in the over-arching architecture, after all, Professor Grobstein did describe a situation in which if one half of a person's brain was damaged (the example I belief was the experience with a stroke or brain aneurism in which the individual did not recall "having" the stroke but was nevertheless aware of something happening in her body even if it was non-specific per- say) and yet the quality of "I"..."I" saw, "I" felt, etc. was still present. Yet, in other cases where the other hemisphere of the brain was damaged in another person that same quality of the “I” persisted. Perhaps the "I" function is a redundant feature as well that exists in multiple areas of the brain whose influence, functionality, etc. can fluctuate depending on what specific processes is being monitored or occurring and in cases where emerging circumstances render one piece non-functional the redundancy or the plasticity of the system can compensate for damage that is done to another part.
im just not seeing the whole "seeing" argument