For me, the most intriguing topic we discussed in class this semester was phantom limb syndrome. It is understandably a painful and emotionally traumatizing experience for those who suffer from it, but it is also fascinating to learn about and study. I cannot imagine experiencing the physically agonizing pain associated with the syndrome, mainly because of the pain itself but also because of the negative consequences it would have on your brain. Your eyes usually provide the most reliable sensory information available, and for them to perceive no appendage, but for your brain to feel a somatosensory response coming from that area–it would be almost impossible to convince yourself that your brain was providing you with false information. The pain has reportedly even driven some patients to insanity. The challenge of overriding information your brain communicates to you is extremely difficult, even when it is not information about excruciating pain. Therefore, I can only imagine how strenuous and difficult the rehabilitation process for phantom limb is.

An article published in the New England Journal of Medicine (http://content.nejm.org/cgi/reprint/357/21/2206.pdf) discusses the option of mirror therapy for patients with phantom limb syndrome. It was theorized in the study that the pain is a result of crossed signals from visual feedback and proprioceptive feelings from the amputated appendage. Therefore, by creating illusions of the amputated appendage, the therapy might be able to trick the visual system into visualizing the source of the pain, and with time and training, uncrossing the mixed signals in the brain. In this study, 100% of the patients who underwent mirror therapy expressed a decrease in pain, while only 15-30% of patients undergoing alternative therapies expressed a decrease in pain. Its very clear that mirror therapy is a successful way to decrease the amount of pain, even if it is impossible to eliminate.

Dr. Ramachandran has researched, discovered, and written so much about phantom limb pain and the cortical plasticity that occurs in phantom limb patients. He has even written about the occurrence of phantom genitalia after sex change surgery! He was one of the first to discover the somatotopic reorganization that occurs in the cortex after amputation in what he calls “the remapping hypothesis” (http://archneur.ama-assn.org/cgi/content/full/57/3/317#REF-NNR8257-10). He has used mirror therapy on patients with phantom limb, hemineglect, and hemiparesis. In his research on the effects of mirror therapy on phantom limb patients, he has found that when many patients experience pain in the phantom limb, it is most likely due to non-existent propioceptive feedback. In other words, there are no signals telling the brain that he/she is clenching his/her fist too hard, but pain is still experienced. However, when a mirror is placed so that the phantom hand appears real, simultaneous opening of both fists relieves the pain (http://www.nature.com/nature/journal/v377/n6549/pdf/377489a0.pdf).

Extensive research on phantom limb has only been going on for about ten years now, and I expect that due to the increase of research dedicated to this syndrome, we will know significantly more about it in the near future.  However, as we learn more about the neural mechanisms of phantom limb syndrome, we must not forget the pioneering work of Dr. Ramachandran and others, for they laid the foundation for further research into this area.

Pre-Renaissance painting struggled to portray a three dimensional world on a two dimensional canvas. Some examples include

http://commons.wikimedia.org/wiki/Image:Altichiero_da_Zevio_001.jpg

http://www.mos.org/sln/Leonardo/PaintingBeforetheRen.html

http://upload.wikimedia.org/wikipedia/commons/thumb/4/46/Merlin_(illustration_from_middle_ages).jpg/550px-Merlin_(illustration_from_middle_ages).jpg

All of these paintings use some kind of occlusion or painting of one object partial blocking another in an attempt to convey a sense of depth. Instead of using multiple depth cues, such as linear perspective, aerial perspective, shading and size principles, or texture gradient, these artists relied almost entirely on occlusion. For small illusions, occlusion is an acceptable, albeit unsophisticated, style of portraying depth, but by no means was it the most effective. It was not until the Renaissance that artists started to incorporate these alternative depth cues into their paintings along with occlusion, and it is from these paintings that the modern principles of depth painting emerged. A good painter could manipulate the addition of these depth cues to convince the brain that it is in fact observing a three dimensional world, while it was merely observing a flat piece of canvas. The primary development during the Renaissance was the mastering of shading techniques, which provide a source of light and can really provide depth, texture, and feeling in an artistic work, especially in folds of cloth.

Artists can also use color and linear perspective very effectively to create depth. Bright, vibrant colors in the foreground followed by medium tones in the middle and cooler, less saturated colors in the background really make you think the scene is real and three dimensional. Linear perspective is very often used, especially in landscape scenes where lines can run all the way to the horizon and converge at the vanishing point. This provides a fantastic sense of depth and really lengthens the image.

You can see examples of color and vanishing point at work in these images:

http://www.mydigitalnoise.com/images/20051031212952_vanishing%20point%20-%20small.jpg

http://www.la-art-tutor.com/wp-content/uploads/2007/10/oppd11.jpg

Personally, I think having synesthesia would be really cool.  In a way, I think it would be similar to what I think the effects of psychedelic drugs would be, but without any of the horrible health aftereffects.  The mixing of the senses like that can almost provide somebody with a “sixth sense” of perception that nobody else can duplicate.  Artists and musicians can use their synesthesic abilities to pioneer new forms of their art or to enhance previous methods.

Reading how each person affected with synesthesia experiences things differently fascinates me, also.  On this MIT website (http://web.mit.edu/synesthesia/www/), various firsthand accounts of synesthetic perception are given, and it is so cool to hear that someone naturally associates pain with the color orange, or that to another, the word linguistics appears “grayish-purple-blue”.   This website also has several simulated synesthesia demos, where you can try to approximate the effects of the disorder.  The coolest part is the Music Animation Machine, where we can attempt to get a glimpse at what synesthetes would see when they listen to different classical composers.  Although we can’t really know if this is what synesthetes actually perceive when they listen to music or not, its still fun to imagine that it is in fact what they perceive, and that this mix-up of the senses can be completely biologically healthy and not harmful at all.

This week I was inspired to write about change/inattentional blindness that occurs during movies. Obviously, the entire movie can’t be shot in one take, so there are going to be discrepancies and errors, but I enjoy trying to find them and pointing them out. The one I always remember the most clearly occurred in the movie Anchorman. Will Ferrell was sitting in his office drinking a beer talking to some of the other guys that work at the news station, and every time they cut to one of the other characters and then cut back to Will Ferrell, the amount of beer in the bottle is different. Sometimes there is more foam, sometimes less. Its fun to try to rearrange the takes in my mind to see what order they actually filmed the scene as he is supposed to drink his beer continually. There are often similar errors in movie fight scenes, where a character gets a slash across the face one minute, and then in the next shot, his face looks perfectly fine! I guess the filmmakers didn’t grab my attention well enough with the fight scene to get me to ignore their mistakes…or maybe I’m just that perceptive!

Another time that you can really notice these errors occurs in video games, especially in sports games. There are glitches in the game where all of a sudden, you’ll be dribbling down the court, turn to your right to pass to somebody on your right, and the ball appears to shoot out your back and go to the guy on your left. Sometimes these glitches can be advantageous.  For example, sometimes in role-playing games, if you run into a certain spot on a wall, you will magically travel through the solid wall and onto the other side! Whether they are intentional or not, these somewhat meta-physical moments are always good for a little chuckle.

Cortical magnification has its advantages and its disadvantages. Predators benefit from cortical magnification because the high-detail vision in the fovea allows them to identify camouflaged prey or to keep it in sight while chasing it. For prey species, it is definitely a disadvantage, because they have the greatest need for sharp peripheral vision in order to identify predators. However, due to cortical magnification, peripheral vision isn’t too sharp, and they might not be able to detect a predator sneaking up on them if it is not in the center of their focus.

For the most part, however, cortical magnification is a good thing. It allows to closely analyze the things that we are focusing on, which can preventing us from harming ourselves, whether its eating a moldy strawberry or noticing the thorns on a bush that we were about to reach into. Our ability for high-detail vision has greatly enhanced consumer products, making them more appealing to look at because of their detailed beauty. Cortical magnification also helps us focus. If we didn’t have one area of high-acuity vision, and photoreceptors’ input was distributed evenly in the cortex, we would lose the ability to read, to avoid the deer standing in the middle of the road, and many more.

To be honest, if at some point in evolution we did not have cortical magnification, I believe that we would have developed it, because it is truly necessary for our survival. Now, we depend on our high-detail vision so much that about 25% of our cortex is devoted to the central 2.5 degress of our visual field (according to this study: http://psy.ucsd.edu/~sanstis/PDFs/Blurry.pdf) That number is mind-boggling to think about, and really demonstrates the importance of our high detail vision and cortical magnification.

“Transformers…more than meets the eye”

That’s for sure.

I can be pretty sure that the writers of the Transformers theme song did not intend for this lyric to have quite as much meaning as it does. Obviously on the outside it refers to the fact that Transformers aren’t just trucks or planes or tanks, but in fact crazy destructive robots. It can also be inferred that the writers were not psych majors, because then the lyric would probably be, “More than meets the photoreceptors, bipolar cells, ganglion cells, optic nerve, lateral geniculate nucleus, and visual cortex.” That probably wouldn’t fit into the song, anyway. Nonetheless, we who know the anatomy and neural pathways of the visual system know that in fact, everything is more than what meets the eye. The only thing that is just what meets the eye is a photon, because that hits the photoreceptors and initiates the chemical/neural pathway that encodes light in the brain and allows us to watch trucks morph into larger-than-life robots. Everything we see is the result of the complex process of vision, the trademark sensory system of the human race. If things were in fact exactly what met the eye, where would we derive our uncanny sense of irony?

I like to consider optical illusions and how they “meet the eye”. In fact, they do quite a lot more. An illusion such as this (http://web.mit.edu/hst.723/www/ThemePapers/Images/esch2.jpg) calls into play our sense of vision as well as a deep interpreting portion of our brain. We are forced to recall our past experiences with staircases (which evokes the part of the brain which deals with memory), analyze whether or not we ascended the staircase and got where we needed to go, or just climbed in an endless loop, and then apply this past knowledge to the image at hand. This is not easy to do, especially since our visual system and corresponding analyzing part of the brain is being tricked by the illusion.

Maybe the writers of the Transformers theme song should have studied a little about the visual system before they wrote those lyrics…maybe then they would have realized that their lyric doesn’t just apply to mutating robots, but to everything that our visual system processes.

Over the break I did a little research on contact lenses, because I wear them and was curious how an object with the same shape could correct for so many different vision disorders, including myopia, hyperopia, astigmatism, and more. I stumbled upon the all-knowing website howstuffworks.com (http://health.howstuffworks.com/contact-lens2.htm) and read a nice little article on the different types of contact lenses (there are more than just one!) and how they work.

I suffer from myopia, and knew that the number of the contact prescription referred to the strength of refraction of the lenses (my lenses are -3.25 and -3.75), but I never knew what the - sign meant. After reading the article, I learned that the - sign refers to lenses that correct for myopia, and + lenses correct for hyperopia. I also learned that minus lenses, even though though don’t appear to be, are in fact concave. I tried to examine my contacts to see the concavity for myself, but I couldn’t really see it, so I’ll have to assume that since my lenses work, they are in fact concave and thinner in the very center than around the edges, thus refracting the light like a normal concave lens like we see in the book.

I was also astonished to learn that there are contact lenses that replace bifocal glasses! Called translating lenses, they correct for myopia at the bottom and hyperopia at the top, just like bifocal glasses. However, the most amazing type of contact lenses I learned about about called corneal reshaping lenses, which do precisely what their name says. You wear these special “ortho-k” lenses at night, and they gradually reshape the cornea, correcting the focal point of the cornea and enhancing your vision! One doctor said they can correct up to 2-3 diopters in just a couple weeks! This is all, of course, a non-surgical alternative to LASIK, and the results don’t seem to be quite as good as LASIK, but for those who are afraid of putting their eye under a laser, this could be a valid alternative.

Our auditory sense serves numerous purposes, helping us to both survive and enjoy aspects of life. Crucial auditory elements to survival are such things as sound localization, communication, detection of imminent dangers (such as the hiss of a snake), and of course, recognition of sounds. Our auditory system also serves recreational purposes such as listening to music. I think one of the coolest features of our auditory system is when it ties in with our cortex and limbic system to provide unique memory-related and emotional reactions to certain audible stimuli. The fact that humans are able to hear a sound and immediately associate with a certain situation or a certain memory–much like what occurs with the olfactory system–truly mesmerizes me and makes my life so much more enjoyable. The fact that people can listen to the first note of a song and immediately know what it is truly shows us the magnificence of the human body and its design.

One of my favorite auditory activities is listening to classical music. As a former cellist and orchestra member, I love listening to orchestral music and using my auditory system to “tune out” certain sections of the orchestra and highlight other sections. This ability is similar to the ability of the eyes to focus on what they want to and not on other visual stimuli. We are very fortunate to have this discerning ability and be able to enjoy the things we are interested in while simultaneously ignoring the auditory stimuli we are not interested in. As a very musically inclined person, I find it very tough to listen to music while I study, because I find myself unable to tune out the music while I study, because I am so interested in listening to the music. This is why I greatly prefer going to the library to study rather than staying in my room, where my roommates may be playing guitar or listening to music, which would greatly distract me.

For this week’s post I am choosing to write about the effects of chemotherapy on gustation. I am able to write a fair amount on this subject because my girlfriend underwent chemotherapy and radiation during her senior year of high school on path to ridding herself of Hodgkin’s Lymphoma. I didn’t know her until last year, and in the year since, have definitely noticed some strange eating habits of hers, but I had never really thought to connect the chemotherapy with her eating habits. For example, she LOVES limes, and other citrus fruits too, which fits in perfectly with the point that chemotherapy causes a sort of bitter taste, and patients try to overcome the bitter taste with sweet/sour things, like limes. She also loves to add salt to her food, which I assume also has something to do with her efforts to overpower her desensitized taste receptors.

Likewise, during her stint of chemotherapy, she developed an extreme aversion to pizza. This was because one day after chemo, her parents took her and some friends to get pizza, and as was pointed out in class, you’re not supposed to eat for a couple hours before and after chemo. She took one bite of pizza and said like she felt like throwing it up right away. Her dislike for pizza continued until about a year after her chemotherapy ended! Now she can eat it just fine…in fact, we just had some for lunch! I find her taste peculiarities very curious, and it’s very interesting to watch her eating habits. One thing I’ve noticed is that her umami taste receptors seem like they weren’t damaged, because she loves sushi and we go to sushi bars all the time. It’s very interesting that her other taste receptors would have been desensitized due to the chemotherapy, but that her umami receptors remained mostly intact.

I am a sucker for good smells. I almost instinctively smell things in a store, and if smells good, it definitely makes me more inclined to buy it. Popcorn at the movies, deodorants/shampoos/soaps in the store, and fries at a fast food restaurant are all examples of products whose smells definitely affect my willingness to purchase them. I enjoy a good scent–it pleases me and even comforts me at times. Certain scents evoke some of my fondest memories; for example, without smelling it, I can envision the smell of my grandma’s house and remember all of the great times my sister and I had there. I think that the subconscious connection between the olfactory system and the limbic system is stronger for me than a lot of people, and I consider myself lucky for this. I do have seasonal allergies–mainly pollen–so I have been trained by my body to not smell flowers, because although they may smell great, they make me sneeze without fail. For this reason, I can hardly ever walk through the department store perfume section, because the way they waft the scents out into the aisles makes it impossible for me to walk through them. Other stores’ smells, however, are very pleasing to me. There is a store in our nearby mall called Wilson’s Leather, and not everything they sell is leather, but the majority of it is. Anyway, you can be walking on the other side of the mall aisle and smell the leather that they waft out into the mall, and even though I have never bought anything from there, I still love to go in and smell around.

I used to work at an amusement park, at the carnival games, and right across the walkway from our games was a Subway store, and every morning, before the park was even open, they would make their bread, wafting the scent of that fresh-baked bread out into the park, and it drove me crazy because I could never leave my post to go get something, although I always wanted to.

I find one of the most peculiar things about smell to be that things that smell good in small or moderate quantities smell absolutely awful when you inhale them deeply. Gas and paint are two examples of these objects that affect me like that. I love the mild aroma of gas in the air at a gas station or the smell of paint in a room when the window is open, but if you get too close to the gas pump or you forget to open a window in the room you painted, the smell can completely overpower you and your body repulses it. It seems peculiar to me that your body would learn not to let so many receptors bind odorant molecules, and thereby limit the intensity of the odor.