Reading Activity Week #3 (Due Monday)

I found the part of the chapter where they explained the way the eye works by explaining the different parts of the eye to be interesting and very helpful in understanding the way the eye works. The Cornea is the outside layer of the eye that protects the eye from things that could hurt the eye. It has no blood supply because it needs to be transparent in order for us to be able to see. Then there is the aqueous humor is the fluid derived from blood that fills the space behind the cornea. Then there is the pupil, which is a hole in the iris that light passes through. The Iris will expand and contract to let the right amount of light in. Then the light enters the vitreous humor where the light is refracted once again. The light then enters the retina. The retina tells the brain where objects are in the room by interpreting the light.
I also found the part in the chapter about the blind spot to be very interesting! I didn’t know until last week that we all have a blind spot in our perception. I did what the book instructed and found where my blind spot was and it pretty much blew my mind.
I found the part of the chapter that discussed the way our eyes adjust to the dark and light conditions to be interesting because it is amazing the way our eyes can adjust to different levels of light. First of all our pupils do their best to control how much light can get in by contracting in adjustment to the light. Our ability to see in various lighting conditions has to do with the way our photopigments are used up and replaced in our receptor cells. If the level of light increases too quickly the eye can not keep up so it just throws some of it away and uses the left overs later. So basically our pupils regulate how much light gets in and the different photoreceptors in the eye throw away stuff we don’t need. Our ganglion cells do their best to deal with contrast by ignoring variation in light level left over.
I think the most useful thing in the chapter for understanding sensation and perception is understanding the way the eye works and how light enters it and what happens when it does.
The part of the chapter about convergence and divergence information and the different cells in the eye was confusing to me therefore I didn’t find it as interesting to read about. These are topics I would like to learn more about.
Terms: Cornea, aqueous humor, pupil, iris, vitreous humor, refracted, retina, blind spot, photopigments, receptor cells, ganglion cells

This chapter was hard for me to complete and pay attention to. For some reason, I have never liked learning about the eyes or really cared for that matter. However, for this class, I have to emit a reacting behavior to the book by answering the asked questions. It was interesting to read about the pupil and the iris and to distinguish between the two. The pupil is what the light passes through into the muscular hole, the iris. The iris is also known for giving us our specific eye color. For instance, mine is an ugly blue when I would rather it be a light brown. Anyways, everyone knows about how when you come into a light room after being in a dark room, your pupil gets smaller and vice versa. What really stuck out to me though was the fact that sometimes when we emerge from a dark room, you may also have a sneeze reflex, known as the photic sneeze reflex. In the book, it discussed how Aristotle thought it was the heat from the sun that set of the sneezing reflex but was proven wrong by Francis Bacon. Currently, they just believe that the sneeze is simply caused by crossed wires in the brain.

Like I mentioned, I find the eye very boring to learn about, but at the same time it can be interesting to think about how each and every part of our eye has a different function and makes it so that we see the things we see the way we see them. Cataracts is a common eye condition that is heard of, but my guess is that most people don't know that the cataracts consist of crystallins and that when there is irregular crystallins, it causes cataracts. Another known term is myopia aka "nearsightedness". Which is what I have. In this case, the light that enters the eye focuses on the front of the retina so distant objects cannot be seen sharply. Therefore, I have glasses to read/see things far away, although I hardly use them. To find out if you have cataracts or myopia, eye doctors will look at the back surface of the eye, which is called the fundus. Arteries and veins from the eye meet where the retina enters the eye and that is the purpose of the fundus.

I especially enjoy having rather good eyesight and being able to see things clearly (even though I do have glasses). If I were blind, or even partially blind, I think it would definitely suck because there is so many beautiful things that you are missing out on. One thing I would definitely miss is the view of nature. I enjoy looking at trees, landmarks, houses, the stars and clouds, etc. The book talks about a man who was unable to see the stars because his eyes could not adjust to the darkness. This condition is known as retinitis pigmentosa. This condition usually will start early but not be recognized until the age of 20 or later. You slowly start to lose your peripheral vision and it can eventually lead to total blindness. Like I mentioned, the thought of having RP and not being able to see would freak me out, especially since there is no cure for it. This happens because the rods are being effected before the cones.

The rods and cones are imporant parts of our eyes, but that's all we focused on in my science class in highschool. I fully understand that the rods are used for night vision, cones used for day and color vision. Not only did the book explain the rods and cones, but went on to explain the outer and inner segments and everything else that has to go along with it. I find this information tidious to learn about and rather boring. I enjoy learning more about what people can or cannot see, than the actual biopsy of the eye. That's why I enjoy learning about myopia and hyperopia, which is light entering the eye focusing on the back of the retina.

Even if I don't enjoy learning about the eye it is still a big part of sensation and perception. Although we do have five senses, without one sense, our lives would be drastically different than those who have all five senses. So yes, I am grateful for having two working eyes and should be more interested in learning about them. The eyes focus more on the perception part than the sensation, at least thats what I believe. We do use our eyes as a sense, but the way we perceive things are more commonly used by our eyes than any other sense.

The eyes are even a cool sensation while we are sleeping because of our dreams. Our eyes are obviously shut while sleeping, but when we dream, are we dreaming in black and white or in color? I always wondered this so before bed I would tell myself that if I remembered my dream, I would try to remember if it was in color or not. Lately, I did find out that I do dream in color, or at least my last couple dreams have been. I think it would be interesting to learn more about that and the studies that have been done, even though that was not mentioned in this chapter. It would also be cool to see more pictures of eyeballs that are not "proper" but have something wrong with them, such as RP or myopia. I found the pictures to be very intruiging and awesome.

Terms: pupil, iris, photic sneeze reflex, cataracts, crystallins, myopia, retina, fundus, retinitis pigmentosa, rods, cones, outer segment, inner segment, hyperopia

This chapter consisted of a lot of definitions of parts of the eye. I never thought that such a small area could consist of so many parts and processes. I had a couple of interesting things come by me while reading the textbook. The first thing I found very interesting was presbyopia. Presbyopia is the loss of near vision because of insufficient accommodation. Accommodation is when the eye changes its focus. This is when our lens adjusts its shape to focus on objects. What I found interesting about presbyopia is that it is inevitable. As we grow older our vision slowly losses the ability to accommodate. This happens because the lens hardens which causes the elasticity of the lens to diminish. This is something that I never knew and it explains why as we grow older our vision starts to decline.
Another topic I found interesting was the section about rods and cones. Rods are photoreceptors specialized for the night. Cones are photoreceptors specialized for daylight vision, fine visual activity and color. These receptors are located in the retina where they convert light energy into neural energy. I didn’t really know the purpose of rods and cones until reading this chapter. I found out that rods operate best under lighting conditions that are dim or dark. Animals with all rods are nocturnal, which I had no clue was the reason for that. Cones on the other hand, help us detect color. I thought that a cone was just a cone; I didn’t know that there were 3 different types of cones that detect different wave lengths. S-cones detect short wavelengths, M-cones detect medium wavelengths, and L-cones detect long wavelengths. These different wave lengths help us to determine differences in color, which rods cannot do because they have the same wavelengths.
One last thing that struck my attention was the fact that light goes through a rigorous filtration process before we actually process an image. Our rods and cones are intercepted by bipolar cells which passes that information on to the ganglion cells. The ganglion cells receive either and on or off bipolar cell. I found that to be cool because these on or off cues provide information about the change in illumination. We are able to detect whether we are in a dark or light area from them.
One thing I didn’t find that interesting was mach bands. I didn’t really get the whole concept on how of we are able to tell the difference between light and dark receptive fields. It’s not that I didn’t find the material interesting; I just thought it was a little bit difficult to understand.
The thing that will be most useful for me in understanding sensation and perception would probably be the whole process our eyes go through when detecting light. I didn’t know it was so complex and had so many stages just to detect light or dark areas that we view.
Things I would like to go over more in class would be Mach Bands, ganglion cells and bipolar cells.

Terms: presbyopia, accommodation, mach bands, ganglion cells, bipolar cells, neurons, m-cones, L-cones, S-cones, rods, cones, photoreceptors, and lens.

Chapter 2 was all about the eye. The biological components that made the eye not only function but allow how we actually see and what all are involved; right down to the different cell types of the same cell. There was a lot of information in this chapter, but majority of it relatively interesting, more interesting than the previous chapter. With biology being one of my least favorite classes is saying something.

One of the interesting things I found in this chapter was the “photic sneeze reflex”. The sneeze reflex is in response to being exposed to a bright light. It’s a phenomenon that isn’t fully explained even today, which considering such advances that we have, was interesting. The sneeze reflex thought to be due to crossed wires in the brain, probably due to that sudden expose of light. I was interested more due to the fact that I don’t sneeze quiet like that, rather the opposite. If I’m having problems being able to sneeze, then I look at the sun or relatively bright light. The same concept but the motive to engage in that sort of behavior is different. Second interesting thing I found with this chapter was that each eye has its own blind spot, one that isn’t even noticed till tested. I had never been aware that there was a blind spot in the eyes till I did the test in the book and sure enough there it was. The third interesting thing I found was the Retinitis pigmentosa or RP disease. Retinitis pigmentosa, is a hereditable disease characterized by the progressive death of photoreceptors and degeneration of the pigment epithelium. The hallmark of this illness of the eyes being the “bone spicules” inside the fundus of the eye. As we all live life with sight, suddenly finding yourself losing it would be severe lose. The fundus being the back layer of the retina, what the eye doctor sees through his machinery to look into a patient’s eyes.

Probably the least interesting thing in this chapter was the concepts of convergence and divergence of information shared via bipolar cells. I understand that bipolar cells are retinal cells that synapse with either rods or cones and with horizontal cells, and then pass the signal on to ganglion cells. I know the process includes further other cells and result in sensitivity and visual acuity to occur. However, the whole general process sort of eludes me. So this would a topic I’d like to further discuss in lecture along with some clarity in the Horizontal and Amacrine cells.

The topic I think is probably useful fro this class, other than the whole concept and biology of the eye, would be the rod and cones. Rods are photoreceptors specialized for night vision. Cones are photoreceptors specialized for day-light vision, fine visual acuity, as well as color. I believe without these more specific cells that vision would be impaired and play a part in sensation and perception as without cones we wouldn’t be able to perceive color at only or it would be impaired; like in color-blindness. Rods are helpful when we’re walking around in the dark in unsafe circumstances. There is certainly more to the eye that could be affected if impaired as the eye is an intricate piece of the human body. I feel they do play a part however in this topic, because if they weren’t, they wouldn’t be in the book.

Terms: horizontal and amacrine cells, rods, cones, sensation, perception, RP, convergence and divergence, bipolar cell, fundus, sensitivity, visual acuity

The main idea of this chapter that I found interesting was the idea or how our eyes adjust to light and dark. The one idea that I was particularly interested in was the how the pupil and iris adjust to the light and dark. This idea was interesting to me because the chapter discuses how this could also be related to when we sneeze. I do believe that sneezing is related to the eyes because I have experienced going into a very bright area and having to sneeze. Also many times when I feel like I have to sneeze and need a little help getting it out I look at the light for that push. This idea about sneezing is also something I would like to learn more about because the chapter doesn’t really get into the details about it, the chapter just mentions that we haven’t really found a reason why the eyes and sneezing are related.

Also going along with the eyes adjusting to the light and the dark, I found the light and dark adaptation to be interesting. This concept was interesting to me because our eyes and our brains are working so quickly to do this. There is so much to the process of our pupils dilating, like our rods and cones and how each of them reacts to the light differently, and our photo pigments and receptor cells. It is amazing to me that all of these parts work within seconds for our eyes to adjust and adapt to the light or dark.

One other idea I found to be interesting was accommodation and presbyopia. Accommodation was interesting to me because it is how we see items that far and close and our eyes adjust to what we are looking at. I also found it interesting that our accommodation declines with age. It becomes harder and harder for older people to see items that are close to them, known as presbyopia and this is inevitable. This was interesting because I always make fun of my parents because they have to hold their cell phones or the news paper further away so they can read them, but just like my parents this will happen to me as well.

Along with wanting to know more about how our eyes and sneezing are related, I would like to know more about the hereditary disease known as retinitis piggmetosa. I would like to know more about is because there has not been a cure found for the disease and because the text in a way describes this as a slower developing disease. And it seems we know that it is something going wrong with the rods to begin with and our peripheral vision. I would like to know more about how fast it develops, why it develops, and why it is hereditary.

The one area I found to be uninteresting was the cones and rods photoceptors. This was mainly uninteresting to me because it was harder to understand it the text. It seemed to me a lot or the terms at this part in the chapter were one after another and it would have helped if they could have explained in more detail what exactly they do, as I got more into the chapter I understood it a bit better.

I believe the concept that will be most useful in understanding sensation and perception would be the retinal information processing and the retina just because it is so complex and I believe it has to a lot with how our eyes and brain perceives things.
Terms: Iris, pupil, adaptation, rods, cones, accommodation, presbyopia, retinitis piggmetosa, peripheral vision, retina

I found several things interesting in chapter two. In particular, the functions and processes of the components of the eye, as well as how the eye adjusts to different gradients of light. Before reading this chapter, I had never given much thought to how exactly my eyes went about seeing the world. Now that I have read through the pages, I realize that this is certainly not a simple process. The eye goes through approximately 9 different processes before the information is actually sent to the brain to be registered. Light first enters the eye through the cornea, which the book describes as the eye’s “window” to the world. This first process was particularly interesting to me because when I was young, I fell as cracked the cornea of my eye. I remember being in excruciating pain, and yet somehow I was still able to see out of that eye (even though the image was blurry). I now know that I was in so much pain because the cornea has strong sensory nerve endings and fibers, thus meaning that this particular part of my eye is particularly sensitive to pain. I also learned that the cornea produces tears to protect its transparency, which is why I was still able to see out of my cornea, even though it was cracked. There are no blood vessels in the cornea, which is why it is able to remain transparent and still allow for images to be seen and processed.
Another process that I found interesting was the retina. Essentially, light that is entering the eye begins with the cornea and ends with retina. The basic role of the retina is to interpret what the light is and where to send it. I found it interesting that only about half of the light actually gets to the eye. This can be the result of a few different variables, one being absorption. Absorption is when light interferes with dust and other particles in the air, or when the environment is too dark. In addition, after the light hits the eye, even less of the light makes it back to the retina. This is due to the long process of registering the incoming light and information being lost from the front of the eye towards the back. This was interesting because it makes me wonder what our eyes are missing out on.
The retina is also involved in a process of adaption. This is when the eye has to adjust to different levels of light. Once the retina interprets the image it receives, the information is then sent to one of two main photoreceptors; rods or cones. Rods are quite sensitive, which is a useful trait for seeing in low light situations. The sensitivity is important because it can be very difficult to see in a dark space, and with sensitive photoreceptors, it becomes easier to find the small pigments of light in poorly-lit circumstances. I notice this when I walk into a movie theater. At first I can’t make out any detail, but once the rods in my eyes adjust to the darkness, I am able to see individual seats and I can even recognize people. The book mentions that it typically takes 30 minutes for the eyes to fully adjust to the dark. Thought there are several positives of having a high sensitivity to light, there are also some negative aspects of this trait. Once there is too much light in an area, the sensitive rods become overwhelmed and are unable to decipher small details. This is why there are photoreceptors called cones. The cones are much less sensitive and are therefore quite useful in well-lit circumstances because they aren’t intending to find small pigments of light, but rather to focus on the big picture. Cones are also sensitive enough to see color. To elaborate on my movie theater example, I experience this when I leave the dark theater and I feel blinded by the bright sunlight after sitting in a dark theater. My eyes then adjust quickly as the cones take over and help to focus in the bright light.
I felt that this chapter had more terms than content because I found myself too distracted by the terminology to focus on the content. I wish the book would have taken more time to go in depth on some of the descriptions of the terms. I suppose this isn’t necessarily a bad thing because not having detailed definitions made me feel compelled to look up the answers for myself, which is ultimately more beneficial for me. I find this chapter relevant to sensation and perception because I was able to come up with an example of how my eye adjusts to different lights. Now that I came up with my own example, I know it will be easier to remember these terms and I will be aware of them when I am experiencing difficulties with my eyes adjusting. Instead of wondering why I go blind when I walk into a dark room, I will know that it only last a short while and that it is just my retina trying to make sense of the image that I am supplying.

Terms: components of the eye, cornea, sensory nerve endings, fibers, transparency, Retina, absorption, interference, adaption, photoreceptors, rods, cones, sensitivity.

The first thing that I found interesting was not the parts of the eye but my ability to recall them from years ago. Once this chapter got into the parts of the eye, the only thing I could think of was the model of an eye that I had to make back it high school (middle school?). I would have gotten a perfect score but I didn’t really do anything for the vitreous humor, I left it as an open space. I guess I could have put a water-balloon in there since my space was big enough. Anyway, the second thing I found interesting (because things are when you can relate them to yourself) was myopia. Mostly because I have it, if I take my contacts out everything turns into blurs of color. Since I know myopia, I have both contacts that I wear daily and glasses that I wear if I can’t get my contacts in (like the fire alarm going off at 12:10 at night and everyone has to leave the building). What interests me is that when I wear my glasses, everything looks like a playhouse mirror. I know my glasses are the wrong prescription because I’ve had them for years so they are close but not good enough for me to want to wear them all the time but for everything to looked so bowed is really disorienting. I can only tell when something is amiss when it is three feet from me (like a door or bookshelf). The third thing I found interesting was how colors only take up 300 nanometers of the wavelength spectrum of electromagnetic energy. It’s almost weird how colors are what is being reflected and not actually on the colored surface itself. There are several ways to play around with this: colored light shining onto a same colored wall, paints and colored lights fixed on one location. The first one is kind of obvious, shine a colored light on a different or similar or multicolored surface and see what colors you can still see. The second one is more fun if you have kids (did in middle school). Try to make white paint out of colored paints by combining the colored paints. Let me tell you, it is impossible! Even when you are going on the idea that the color ‘white’ is all of the colors of the rainbow being reflected back into your eye. Unfortunately if you try to combine all of the colors of the rainbow with paints then you will be left with one sickly green color. But it you combine many colored lights, then you can get ‘white’.

The different cells in the retina and their functions had me really struggling to stay focused. I know they are important but I always struggled with retaining information when I have not deep interest in the subject of biology.

How we perceive colors. Colors play a really big role in our world and I think it would be interesting to see how color fits into our society like the way it does in the animal kingdom.

Blind spots would be the first one, but not just how the eye doesn’t send data due to the blind spot but how the brain can fill in something that is simply not there. And also more about how the eye sees in the dark. When I went to the planetarium show here at UNI, the ‘tour guides’ told us that they used red lights to lead the way so that when you look back up at the stars you can see them because it takes your eye less time to adjust from red light than any other color light.

Terms: eye, vitreous humor, myopia, contacts, colors, nanometers, wavelength, spectrum, electromagnetic energy, reflected, retina, and blind spot.

I enjoyed reading chap 2 because it had good diagrams that made understanding the terms much easier and that it also had interesting stories. One story that I enjoyed was the story of the photic sneeze reflex. This happens when you move from a very dark area into a bright area. I have never noticed (or recall it happening), but I know I will definetly notice if it happens to me. I think it would be a sweet way to impress your date if it happened to you as you were coming out of the movies. Learning about presbyopia was something that disappointed me. I always knew that people's vision gets worse as they get older, but I never knew it was something that was inevitable. It surprised me that your lens become harder and that the capsule the encompasses the lens are less able to change shape causing peoples leaven of accommodation to decrease. I have noticed that my parents have had trouble seeing as they got older, but I didn't understand that it was due to presbyopia. I have seen both of my parents get bifocals. Learning about how the eye works is something that I have been learning about for years but this chapter went into way more detail than I had ever done. I had never learned that the eye had photoreceptors that specialized for day (cones) and night (rods) vision. The examples of rats, owls, and lizards that have mostly cones, didn't make sense to me. These animals spend most of there time awake at night or in dark spaces, why wouldn't they have more rods for night vision? These topics I found to be the most interesting to me because I understand them and I can think of examples from my own life.

The thing that was most difficult for me to understand was all the terms. I frequently had to go to the terms on the side of the text to dry and decifer what the authors were trying to say.

I would like to learn more about different cells in the cells. I would just like some good clarification on this section so that what I read I am understanding correctly.

Terms: presbyopia, lens, accommodation, photoreceptors, rods, cones

I found the information regarding the two photoreceptors, rods and cones, to be interesting because of the functions they serve for the retina of the human eye. Certain animals have more rods while others have more cone retinas. We as humans have more rods than cones, by around 85 million. It’s fascinating to learn how complex something as small as the naked eye looks. Furthermore the work done by Austrian physicist Ernst Mach introduces the idea of illusion. The Mach bands in his visual image appeared to be present but are in fact illusions from the visual system. The brightness of the light and dark visual image varies where physical intensity doesn’t. Mach proposed that this was due in part to lateral interactions within the retina. Retinitis pigmentosa, as seen in the man who could not see stars, is a very interesting, but awful condition. This particular disease is hereditary in nature and leads to the deterioration of pigment in the eye. This disease may take many years before it slowly starts to take notice in individuals. The ultimate cause of the disease is complete blindness. This is an interesting disease because of what we often times take for granted. Our perception of how the world looks is because of the complexity of our eyes with rods and cones, and millions of photoreceptors. Along with this information, I believe one of the most important topics used to understand our sensation and perception in the eye are how we see light, and the importance that light has on our vision. Rods and cones are essential for the detection of wavelengths and cones are important for our vision of color. It is also interesting to note the differences in people with color blindness. This was a difficult chapter to grasp because of how complex the eye is. There are two bits of information that I would like to learn more about and how they affect the sensation and perception of our visual process. Those two concepts are bipolar cells and midget bipolar cells.

Terms: photoreceptors, rods, cones, Mach band, retinitis pigmentosa.

I have to say. I am having kind of a hard time picking only three things that interested me to talk about. There were so many things that piqued my interest in this chapter. I will admit that it was somewhat hard for me to grasp some concepts in this chapter. I am definitely a visual learner, so I had kind of a hard time visualizing things especially when it came to reading the descriptions of the interaction between the different neurons:Rods, Cones, Amacrine cells, Bipolar cells, and Ganglion cells. Something that I noticed as well, which is a coincidence considering the chapter, is how light glares off of the book page unless you have it at the right angle or with the light coming from ahead of you rather than behind you.

Well now that I finished my little rant. I think my favorite part of the chapter, hands down, was the section on the fundus and optic disc which causes there to be a blind spot in our eyes. I really loved doing the two activities in the book that had to do with showing the blind spot in my eye. One involved closing your left eye and focusing on the letter F while looking at a red dot in your peripherals and moving the book closer and further away until you cannot see the red dot any more. The other exercise showed how your visual system fills in the blind spot based on the surrounding area. It showed two lines separated with a space that seemed to be one line when pulled into your blind spot. I enjoyed this section so much that I went and showed one of the roommates the exercises.

I found the differences between Rod and Cone Photoreceptors very interesting. I liked learning about the fact that there are way more Rods than Cones, and the different functions these Photoreceptors carry out. The fact that no Rods exist within the center of the fovea, and the fact that the Cones are spread throughout but are concentrated in the fovea.

The section on Mach Bands was interesting. It is crazy the illusions your visual system plays on you. I think the description of it looking like a ramp was really interesting. I did like this section a lot, but I did find some of this section to be kind of confusing. Maybe this is just because this section was towards the end of the chapter.

The least useful part of this chapter was the section titled "The Man Who Could Not See Stars." I found it interesting, but it seemed kind of out of place. It presented a visual disorder, but I am not sure that it was all that necessary. I think it was just simply a convenient story to put at the end of the chapter. I really want to learn more about the Rod and Cone cells and the third Photoreceptor that scientists think might exist. I also want to learn why the Rods and Cones are distributed throughout the retina the way they are. This chapter as a whole was just mind blowing to me.

The first topic that I found interesting was the physical properties of light. Even with many different experiments trying to understand and classify light, it still remains somewhat confusing and an anomaly in physical science. How can some facet of nature have properties of a wave and a particle? The book subtly dismisses the complexity of the photon, but to me it still seems very odd.

The second topic that sparked my interest was the vitreous humor. More specifically, how biodebris can remain floating in it. Biodebris is responsible for the snake-like "floaters" that you may see throughout the day.

However, the most interesting topic in the chapter (and one I would like to learn more about) is the arrangement of visual cells and how the arrangement creates analysis of the complex visual world. Examples of the specific layout would be the lateral cells that inhibit one another and the "vertical" cells that converge and diverge information. Much like the example you showed last class period by creating a simple visual system by just three neurons, the structure of the visual system is just a very advanced and complex system of this type of pattern. The visual system makes up a complex hierarchy, which each advancing level filtering and selecting specific stimuli that eventually creates a finished product by the time is arrives at your occipital lobe. Not only is the visual system hierarchical, but cells in the same "level" work together enormously. Using the "center-surround receptive fields" as an example, neurons are excited by either light or the lack of light in their specific area. The complex map that these sensors send to the bipolar and ganglion cells.

The least interesting part of this chapter, to me, was the anatomy of the eye. The reason for this is not because this section isn't interesting, but it's just I already know most of the anatomy. However, this is an integral part in the chapter for giving students and spacial representation of the eye.

The most important lesson that I learned in this chapter about sensation and perception is that seeing is not always believing. Or, more scientifically put, what you perceive is not a very accurate representation of the actual world. This can be shown by mach bands, and how the structure of the visual system makes edges and sharp contrasts look more sharp than they really are. This most definitely has evolutionary reasons, but the point remains: your perception is not very accurate of reality (very Cartesian).

As expressed early in the post. The two topics that I would be interested in learning more about would be the physics of light and convergence & divergence / lateral inhibition (or the structure of visual neurons in general).

Terms: photon, vitreous humor, biodebris, occipital lobe, bipolar cells, ganglion cells, mach bands.

Chapter 2




1. The first thing I really enjoyed reading about Chapter 2 is the history of the physiological approach. I thought it was interesting that in 4th century B.C. many Greeks believed that the mind and soul was the heart. So in historical history the greek genius’s did not believe the brain was responsible for the health, thoughts and emotions. The heart was said that the spirits flowed in the cavities. I thought this was interesting because it wasn’t until 1664 that a Physician studied animals and concluded that the brain was responsible for the mental functioning. I never knew that it took so long for anyone to realize that the mind functioning was not controlled in the head. 



2. The second topic I enjoyed reading was reading about how signals travel in the neurons to the brain. I thought it was interesting to learn that neurons is a large network and transmits signals to the brain. This is activity used to see, hear, and use our other senses. Without this powerful network signals, sensation or perception would not be able to take place. The brain uses the signals to recognize how to interrupt the environment around us. There are different parts to a neuron like a cell body, and nerve fibers that allow the process of electricity to take place.



3. Receptive fields was interesting because it is the area in a neuron that influences the firing rate of the neuron. This step is important because it increases the cell response to send signals to the brain. A diagram in the book shows that when the stimulus size is increased and illuminated there is a decrease in the firing rate. The diagram shows the cell starting with faster receptive fields and ending in slower firing rate when the stimulus is increased.



*One thing I did not enjoy about this chapter was all the technical terms and trying to understand the process of the cells. The diagrams showed adequate drawings, but I had to look up videos to completely understand what Chapter 2 was taking about with face coding from neurons and how a signal is transmitted to the brain and what part of the brain it goes too.



*I really enjoyed the face coding section in the chapter that shows how each stimuli neuron is detected for a different face. I would like to learn more about face recognition and how we perceives “attractive people.” 



*I think everything in this Chapter is useful in understanding how sensation and perception works in everyday life. Once again, many people do not understand that there is so many little networks working together to see one object or hear a crowd of people. This chapter shows the technical electricity in the brain and how cells and nerve fibers work together.



In future chapters I hope to learn more about disorders of perception and sensation and more easier examples on how the brain processes pleasurable perceptions versus aversive objects?