Oremeika's Weblog

Final Blog Entry

oremeika — Mon, 28 Apr 2008 01:28:35 +0000

One of the most interesting parts of this course for me was actually not something that we directly covered, nor something that we even discussed very often, yet it is one of the most crucial parts of all the sensory systems that we have been learnig about: efficiency. We’ve spent this term talking and reading about the intricacies of the central nervous system, and how vital its use is to our everyday lives. From a rabbit seeing a predator approaching, to a baseball player hitting a pitch, we perceive things at an astonishing speed, and with incredible accuracy. This is what I think made this course so interesting: learning about how complex our brain is and how it allows us to see, feel, smell, taste and touch, while keeping in perspective that all of the information is obtained, processed, and interpreted in a fraction of a second. Seeing is one of the best examples of this, and in my opinion is the most fascinating of all the senses (and the one that I have already said I would least like to loose: see blog entry “hearing vs. vision: the showdown”). Imagine you are the third baseman for the Boston Red Sox. The pitcher hangs a curveball, and a hitter hits a hard linedrive down the third base line. From the moment the pitcher releases the ball, to when the batter makes contact, to when you make Sportscenter’s top playes with a diving catch, is less than a second. Consider now what this third baseman needs to see in order to make the play. First, he needs to see the pitch. Assuming that the baseball is travelling 90 miles per hour, that means that from when the pitch is released to when it reaches the hitters bat, about 0.46 seconds have gone by. In this time, light must reach the retina, be absorbed by photoreceptors, get through the horizontal, amacrine, and bipolar cells, have an action potential from the retinal ganglion cells travel along the optic nerve to the LGN, where motion is picked up, then the LGN must transmit information to the V1 area for local motion detection using direction sensitive cells, then information must be passed to the MT area where the motion of the ball is further analyzed, and finally the information from all of these calls and areas must be processed in the MST area, where not only the ball is registered, but the pitcher’s bosy position, the runner on first breaking to steal second, and the batter taking swings in the on deck circle. And this all takes place in less than one half of a second. The situation becomes even more complicated once the batter hits the ball. According to Jonathan Drobnis (http://ffden-2.phys.uaf.edu/211_fall2002.web.dir/Jon_Drobnis/bmb.html), if a player swings his bat 70 mph and connects with a ball going 90mph, the resulting speed, is close to 160mph. For the third baseman, this mean that he has less than 0.4 seconds until the ball reaches him, and there’s still a lot to be done to make the play. First, the ball must be seen. All of the connections just described would have to occur, as well as all of the necessary analysis of information, and the command impulses that would have to be sent to muscles in order for him to dive to his right, stretch his arm out, and close his glove around the ball, and remember, all of these commands, from pitch to catch, are occuring in less than 0.9 seconds.

Seeing is just the example I chose to use to show how efficient and accurate our sensory systems are. Touch hearing smell or taste are all extremely efficient, and would all provide excellent examples of the speed with which we process the events in our lives. If we were not able to perform these functions as fast as we do, or if our brain did not evolve in exactly the way it has, our lives would be drastically different from the way they are now. There are simply too many examples of how impressively fast our processing centers receive and interpret information, but I hope the one I used is a good one to give an idea of how fast everything that we have been learning about this semester happens. This blog entry was supposed to be about the most fascinating this we learned this semester, and I wrote about something we rarely, if ever, discussed. Why? Because evev if it was never explicitely stated, and no matter how long it took us to learn the pathways required for pain sensation, or color perception, the actual events that we were discussing happen every moment of the day, and happen faster than I can really appreciate or understand.

April 27, 2008

where to place the eyes?

oremeika — Mon, 21 Apr 2008 04:38:46 +0000

I have been trying to imagine what life would be like if humans had eyes on the sides of their heads like prey animals pretty much since we began our study of the eye. Obviously from a simple “predator/prey” point of view, it makes evolutionary sense to have our eyes on the front of our heads rather than the sides, but given our extreme dominance on the food chain, if we now had the choice, which of the configurations would we choose? From an aesthetic point of view, it would be ridiculous looking for a person to have eyes on the sides of their head rather than on the front of their face, but looks aside (no pun intended), would humans benefit from having eyes on the sides of their heads?

For the most part, humans are untouchable on this planet in terms of evolutionary dominance. There is not even the slightest chance of our being challenged by anything else for control of the food chain, so thinking of us as either a predatory animal or a prey animal doesn’t really matter. My question, is what would life be like with eyes on the side of our head, and if we were able to choose, would our visual life be richer or more useful if our eyes were moved to the sides of our heads, rather than the front? The negatives of having eyes on the sides of our heads seem clear: a significant decrease in binocular vision; however, I think that the benefits of having eyes on the sides of our heads outweigh this negative. Animals with eyes on the sides of their heads simply see much more of the world. Think about how hard it is to sneak up on a rabbit. Because they can see much more of the world around them, it’s nearly impossible to get to them without you knowing that they’re coming. Now think about how many car accidents are caused every year by people who do not see cars that are in their “blind spot,” with eyes on the side of your head you would be well aware of the other car and would not get into one of those accidents. While the loss of binocular vision is a concern, we look at everything we pay attention to straight on. Think about reading this blog entry. You are staring straight at the screen, and while you are able to see the 3D form of the water bottle sitting to the right of your computer, if you are going to pick it up, you are going to look directly at it before you try to grab it (in most cases). My point is that the objects its most important to see with binocular vision are objects that we are staring straight at, and with eyes on the sides of our heads, we would still have binocular vision for these objects. I do not know what living with eyes on the side of my head would be like, and I probably never will. From an evolutionary standpoint it makes sense for us to have our eyes positioned where they are, but from a conceptual position, I wonder if we wouldn’t now, all other things remaining constant, be better off with eyes on the sides of our heads.

April 20, 2008

I’m color blind, and that makes you better than me…

oremeika — Mon, 14 Apr 2008 03:06:02 +0000

I was first told that I was color blind when I was about 12 years old and got glasses for the first time. I was at the eye doctor’s and they gave me the Ishihara test for color blindness…I got 1 of 20 right, and it was more or less a guess. The funny thing about it is that I had been living for 12 years, and until that point I didn’t know that I was color blind. Since then, every time that I go to the eye doctor’s I get tested, and every time I fail in spectacular fashion, but if I had never been tested, I would probably never have known that I was severely color blind. I don’t see the world in black and white, and if someone were to ask me tomorrow what color their shirt is, I would be able to tell them without hesitation. I do not see the world in shades of gray, and I am able to appreciate a sunset or garden as much as anyone else, essentially, my color vision is not really that different from anyone else’s. As it was explained to me, since I was a child I have been learning what to call the colors I see, whatever they may be. When I was a kid, I was told that the sky is blue, grass is green, blood is red, and the ocean is blue (or a murky shade or garyish-brown in the case of my home town of Boston). I see all of those colors as shades, what shade I cannot really be sure, but a specific shade, unique and identifiable from other shades. I also began learning at a specific age the locations of certain colors. I know that when the bottom light of a stop light is illuminated, that that is a green light, yellow above that, and red above that. I also learned that my house is painted a light shade of blue, and that when I grab an orange, that the color I am seeing is orange. While all of this may seem confusing or hard to do on a day to day basis, I have been learning to distinguish different shades, or know the locations of certain colors since I was so young, I don’t even know that I am making the associations I am making when I perceive a color. The only time that I really know I am color blind is when I go to the eye doctor’s, or when Professor Boucher puts displays up in class that test for color blindness, normally, I don’t even know, or think about the fact that I am color blind.

There are occasional times that I am aware of my colorblindness. Colors that are similar to one another are very hard to tell apart, and I occasionally run into problems when I match clothing that I am subsequently told clash horribly (although this might just be a lack of fashion sense more than an effect of colorblindness). There are also times when I will mention the color of an unfamiliar object and am told that I was way way off on the actual color, but aside from these times, none of which really have drastic consequences, my colorblindness has not had a major impact on my life, its more of a conversation piece than anything else. So while everyone else might have “better” color vision than me, if I hadn’t told you that I was colorblind, you never would have known.

April 13, 2008

evolution and prosopagnosia

oremeika — Mon, 07 Apr 2008 04:20:30 +0000

Of all the disorders we have covered and discussed in class, prosopagnosia has been the most difficult for me to imagine living with. While I understand that different areas of the brain are used in different stages of vision and recognition, but I cannot imagine what the evolutionary benefit is of having such important and necessary processing centers relegated to one are of the brain only. In an evolutionary sense, the ability to recognize faces seems to be paramount. It would be crucially important to be able to recognize a friend from an enemy at a distance if you were living in a hunter-gatherer world. This ability is so important that it seems foolish to have the location or locations necessary for it to all be located in one area of the brain.

While it is not concretely known which area of the brain cause prosopagnosia when damaged, it appears that damage to the right inferior temporal lobe is closely associated with the condition, as most patients who suffer from prosopagnosia also have damage to this area of the brain. While it might seem somewhat strange to consider the evolutionary benefits of planning for brain damage, it strikes me as strange to isolate such an important system to an area that can be damaged. However, back to my original point: what would living with prosopagnosia be like? What would it be like to see your mother, or roommate, walking towards you, be able to see and identify their ears and cheeks and facial features, to even be able to tell what color their eyes are, but to not be able to remember their name. Try as I might, it seems to be an impossible thing to do, there’s simply no way that I can imagine not being able to remember that anyone’s face looks like. One of the most interesting aspects about prosopagnosia, is that it does not alter your ability to remember a person’s voice. If you were suffering from prosopagnosia, and your mother and a complete stranger was standing behind you and called your name, you would turn around and expect to see your mother, but instead you would see two people who as far as you could tell were both complete strangers.

I find prosopagnosia to be a fascinating condition, in part because it is one that I cannot possibly imagine living with. While we have moved on to development, I wanted to use this blog entry to briefly talk about what I find to be one of the most interesting items that we have covered this term.

April 6th, 2008

Gestalt theory and Geons

oremeika — Mon, 31 Mar 2008 03:36:44 +0000

Two of the theories that we have been discussing regarding object recognition are the gestalt theory and geometrical ions, called geons. I have heard of both of these theories before, and both have always struck me as overly simplistic. We are able to identify by sight countless objects that we encounter in our everyday lives. Even in the absence of color and markings that might give us additional clues to an objects identity, we are able to quickly identify so many objects, of such varying shapes, that I find it hard to believe that either of these views accurately describes the incredibly complex processes that our visual brain must go through in order to properly identify objects.

The geon theory is the less plausible of the two for me. The world we see is made up of so many objects, of such varying shape and complexity that I find it difficult to believe that it can really be broken down into a number of goens, that can be distorted to form any object that we see. Obviously the world is made up of different shapes, and certain objects like a phone, mug or briefcase like we looked at in class can be broken down into only a few geons, but in order for the theory to be relevant, the world would have to break down into a reasonable number of geons. This is where the theory breaks down for me. Considering the complexity of the objects in the world, I cannot imagine that anything less than several million geons would be able to cover every object that we are able to identify, and with so many, the point of the theory, that the world is easily classifiable, is gone.

The Gestalt theory makes more sense to me, but even it makes the process of object recognition seem too simple. The Gestalt theory says that objects are grouped by proximity, similarity, closure, good continuation, and common fate. This makes sense to me because when we see a complex scene, we are able to see most things as different objects, or belonging to a group, like different people walking in a crowd, or a flock of birds flying through the sky. I think that especially with regards to good continuation and common fate the Gestalt principles make some very good points about our object recognition systems, however, even though I think the theory makes some good points, and makes much more sense than the geon theory, I still think that the gestalt theory is too simple. I have a hard time going from identifying a general object in a certain area to being able to identify your cousin in a picture of his third grade class.

All in all I think that both of the theories have pros and cons associated with them. While I do not have a better suggestion than either of these for how we are able to recognize and identify objects, I think that other theories, perhaps incorporating aspects of both, would give a better general description of how our visual system works.

March 30, 2008

bionic eyes and cochlear implants

oremeika — Mon, 24 Mar 2008 03:46:34 +0000

At the beginning of chapter 3, the text book says that in order to appreciate the complexity of the eye, you should try to build a bionic one. Obviously this would be an incredibly challenging thing to do, but how much more complicated would it be to design a bionic eye than a cochlear implant? Obviously I am thinking about these two devices in a conceptual way, as I have no engineering background and no idea of how complicated the mechanics of what I am talking about would be, but that being said, I an surprised that bionic eyes have not become as advanced or common as cochlear implants are.

The reason that I am surprised, is because I don’t see how the two would really be that different. Cochlear implants transform sound waves into electrical impulses, which the brain can interpret as noises. Why would a bionic eye be able to do the same for the energy waves that we interpret as light and color? A video camera is able to transform light entering the lens into electronic signals, that are able the be interpreted and either recorded to a tape, or projected onto the camera’s lcd screen. I do not see why a bionic eye would not be able to transmit the electrical signals that a video camera can produce via specifically placed electrodes to the vision centers of the brain. Obviously the visual system in a human being is incredibly complicated, and the science involved in actually placing the electrodes into the brain would be phenomenally complex, but after our study of the auditory system, I’m not convinced that the electrodes in cochlear implants are much less intricately placed. However, despite the seemingly similar conceptual aspects of bionic eyes and cochlear implants, cochlear implants seem to be far easier to make and implement into patients than bionic eyes are. What makes the electrode design and placement so much more difficult in the visual system that bionic eyes are years behind of the advances that have been made in cochlear implants? As we continue to study the brain systems involved in vision, I will be interested to see if there is anything about the location of these systems, or the mapping of theses brain areas that would make the placement of the electrodes so hard, it would account for the difficulty of construction of bionic eyes, or if it is something else about the device itself that makes them so much harder to make than cochlear implants.

Sunday, March 23

Color Vision

oremeika — Mon, 17 Mar 2008 01:48:45 +0000

As we enter our section on vision, I find myself again considering what exactly color vision is. Several years ago, one of my friends offered a view on color vision that still botheres me to this day: how do I know that the color I see as blue is the same color that everyone else sees as blue? Obviously when someone asks me what color the sky is, I do not say it is purplr, or orange, but what if another person were able to view the world through my eyes, and actually did see the world in different colors than what they were used to. I don’t know if this will make much sense to anyone else, or if I am describing the question well, but the core of the question essentially comes down to what is a color. A science teacher will tell you that a color is light of a certain wavelegnth reflecting off an object. They will then go on to tell you that each specific wavelegnth in the visible spectrum is associated with a certain color. However, is there any way to prove for certain that every person’s brain interpretes these wavelegnths in the same way. For instance, when I was a very young child, younger than I can remember, someone told me that grass was green. Everytime I see grass I know it is green, and anytime I see a similar color I know that it is also green. However, I was dropped on my head just hours after birth. What if some of the connections in my brain that associate colors got switched around, and what I see as green was actually the color that everyone saw and called red? If i were able to view the world through someone elses eyes, would a cut on my arm start leaking “green” blood? I know that this is a far fetched concept, and usually it comes up as a topic of conversation between me and my friends when were writing papers at 5am and are deleriously tired, and the concept of switching bodies seems plosible, but colors are just our interpretations of certain wavelegnths of light reaching our retinas, and how can we be know that our brains interpret these wavelegnths the same way? If we could experience life through someone elses eyes for a day, how different might the world look?

On a similar, but much less far fetched train of though, I will be interested to see if we cover color-blindness during this section of the class. I am color blind, as is almost every other male in my family, but as far as I am concerned, I see most colors just fine. If you asked me what color shirt you were wearing, I would be able to tell you. I can tell you what color a car is, or what color backpack someone is wearing, but if you hold up a piece of paper with colored dots and a number in different colored dots, I would never be able to find it. As we continue with this section of the course, I will be interested if we cover color-blindness to see, how it is possible for someone who is color-blind to differentiate colors, if “black-and-white” color-blindness is possible, how anyone can be sure, short of dot-tests, that they are not color blind, and how you can know you are saying the grass is green because you can see that it is green, and not simply because when you were a very young child, someone told you that grass is green.

March 16, 2008

auditory illusions: ventriloquism

oremeika — Sun, 24 Feb 2008 03:11:30 +0000

After our experiment in which we experienced hearing loss, I became increasingly interested in the ability to localize sound. We can tell where a sound is coming from incredibly fast. When we drive a car and we hear another car’s horn, we can tell where it is without even looking, allowing us to swerve to avoid a crash. When I play golf and I hear “fore!!” coming from another fairway, I can tell without seeing the golfer who yelled, where the ball is coming from and which way to run. The experiment made me even more interested in the ability to localize sound, after I walked through campus with only one earplug in. I thought that my ability to localize sounds would be completely shot with hearing limited in one of my ears. But it wasn’t. Sure it was effected by the earplug, but in general, if a fried who was across the quad called my name, I would still know where the sound was coming from.

All of this got me thinking about ventriloquism. If having an earplug in one ear was unable to have an effect on my ability to localize sounds, how are ventriloquists able to make people hear their voice coming from a puppet on their lap? I have always been interested in ventriloquism, as one of the creepiest forms of performance in the world, and this experiment made me finally hop on the internet and find out how it works. While the Wikipedia article I read goes into considerably more detail about the brain functions that make ventriloquism possible, it turns out that ventriloquism is nothing more than a visual illusion. We are so used to associating speech with a moving mouth, that when we hear the words, and see the puppet’s mouth move, our brains tell us that the sounds are coming from the puppet’s mouth rather than the ventriloquist’s. Ventriloquism is nothing more than merely training so that you can speak words without moving your lips, tongue, or throat in a noticeable way.

I was disappointed that there was nothing more impressive behind ventriloquism, but if nothing else, this experiment and our discussions in class lead me to finally answering a question I had had for a long time.

FEBRUARU 23, 2008

Vision vs. Hearing: The showdown

oremeika — Wed, 13 Feb 2008 09:53:36 +0000

“Blinness cuts me off from things; deafness cuts me off from people” -Helen Keller

This quote which Professor Boucher put up in class got me thinking about blindness and deafness. If I had to lose one of those senses today, which would I choose? Would Helen Keller’s words ring true for me? Or would the opposite be the path I would choose if faced with this unimaginable choice? This blog entry is not so much about the science of sight or hearing, but about its effects on my world, in my analysis of the choices, I considered how losing either sense would change my world:

Deafness: there’s no question, deafness would change almost every aspect of my life. Right now I’m sitting in my room, listening to a song that I would never again be able to hear. A shout from a friend across a room, or on the paths would go completely unnoticed. Driving a car would become impossible and illegal. I would never be able to hear a friend’s laugh, or a cry for help. Being plunged into a world of complete silence would be terrible. Beyond the simpler sounds, not being able to hear would make going to class extremely difficult, and i would probably have to leave Vanderbilt for a special school for the deaf. I would not be able to listen to instructions from a teacher, or boss, making normal employment impossible. And all of this is without the mention of the inability to hear fire alarms, the screeching brakes of a car hurtling towards you after it ran a red light, or the “fore!” that a golfer hears when an errant 9-iron is heading at them. I believe that Helen Keller felt that this was the sense that separated her most from the world, because for someone who has never been able to hear or see, this is the sense that would lend the most immediate information about the world. being able to hold a conversation with another person would be able to give her insight into the world that she has never had before. However, I believe that had she grown up with all of her senses intact, and only lost them abruptly, as would be the case with myself or anyone else in the class, she would not find her deafness to be the most dabilitating, or isolating sense to lose.

While I do not in any way mean to suggest the deafness would be easy to deal with, or that I could quickly adjust to it and live a normal life, I think that losing the ability to see would be far worse, far more devastating, and far more isolating to me. I spent the last day paying attention to all of the facial expressions I saw on my friends’ faces, and how much information I gathered from them. The smile that told me my friend thought his randwich was particularly mediocre that day, or the worried look that told me my friend was having a hard time with his statistics homework, and every other thing that I am able to read about people from facial expression or body language, without a word being spoken, are so important in my life, that i think losing the ability to see these things would cut me off from people much more than not being able to hear them. While normal conversations with most people would obviously be extremely difficult to have, sign language and lip reading would be able to make up for a portion of the personal conversations I would have if I were deaf, but not being able to see what a person looked like, or to never read a book, or see a painting again, I think would be much more isolating than not being able to hear a song, or listen to a person talk.

Obviously I have no idea what either sensation would truly be like, and I hopefully will never have to experience either. I think that our upcoming experiment involving earplugs will be very interesting, and will give me a better idea of what living with deafness would be like, but I also believe that it will only reaffirm my feeling that if faced with the decision I would sooner give up my ability to hear than i would give up my ability to see. I believe that Helen Keller felt that hearing was the sense that cut her off from people more than vision, because it is the sense that would provide her with more immediate information about the people she knew, but after careful thought, I believe that for a person who has lived their whole life with both senses intact, like me, the loss of the ability to see would cut us off from the world and the peole in it much more than losing the ability to hear would.

FEBRUARY 13, 2008

Remember that smell…

oremeika — Sun, 20 Jan 2008 17:18:09 +0000

When we started talking about our sense of smell this week, I began thinking about all of the ways in which smell affects our lives. Smell can protect us from eating rotten food, entering areas with potentially harmful, noxious odors, and alert us to other dangers in our environment (fires, gas leaks, etc..) long before any of our other senses alert us to them. But the aspect of smell that I find the most interesting is the connection between smell and memory.

Almost every memory has an aspect of smell to it. When I think about my dog, or my house, or my parents, or my dorm room, or the golf course that I play when I’m at home, I can almost always associate a smell with them. With the exception of particularly strong smelling things, like my dog or dorm room, the smell might not be a major factor in a memory, it often is something that I have to think specifically about, but it is always there. Smells can also conjure memories unintentionally. How are memory centers in the brain connected so that if I pass a complete stranger who is wearing the same perfume that my mother wears, I have to turn around to make sure that my mom isn’t in Nashville? And why, for that matter, is smell the only sense that can do that? No other sense has the ability to evoke a completely random memory like smell can. The other day I was having dinner with a few of my friends, and the smell of the food suddenly made me think about my grandmother’s funeral, which happened my freshman year of high school.

As we continue to look at the olfactory system, I will be interested to see how the memory centers in the brain are connected, so that a smell, even a faint one, can evoke strong, sometimes long-forgoten memories so quickly.

Feb. 2, 2:32pm