What I would like you to do is to find a topic from chapter 3 that you were interested in and search the internet for material on that topic. You might, for example, find people who are doing research on the topic, you might find web pages that discuss the topic, you might find youtube clips that demonstrate something related to the topic, etc. What you find and use is pretty much up to you at this point. But use at least 3 sources.
Once you have completed your search and explorations, I would like you to say what your topic is, how exactly it fits into the chapter, and why you are interested in it. Next, I would like you to take the information you found related to your topic, integrate/synthesize it, and then write about it. At the end, please include working URLs for the three websites.
By integrating/synthesizing I mean to take what your read/experienced from the internet search (and from chapter 1 if you like) organize the information into the main themes, issues, info, examples, etc. about your topic and then write about the topic in your own words using that information. This is hard for some people to do - many students write what we refer to as "serial abstracts." They are tempted to talk about the websites rather than the topic proper. They will talk all about website #1, start a new paragraph and talk all about web site #2, start a new paragraph and talk all about web site #3, and then write some kind of conclusion. Serial means one after the other...This what you DON'T want to do!
At first it is a real challenge to get out of the habit of writing "serial abstracts," but I assure you once you get the hang of it it is much easier to write using the integration method. And besides this is the way researchers and scientists write their technical reports and findings - many of you will have to be able to do this for other classes and for jobs that you may eventually be hired for so now is a good time to learn this skill. At this point don't worry about a grade, worry about doing your best to have fun with the topic and then integrate it into your own words to share what you found and now know. We will work on citing the sources later....
Let me know if you have any questions.
After reading chapter 3, I was left wanting more information on Strabismus. Strabismus is a condition in which one eye is turned so that it is receiving a view of the world from an abnormal angle. The text gives a brief description of this condition as well as explaining that if it is left untreated during the critical period (for humans it is 3-8 years) then it can never be reversed. I decided to research this topic because I want to know more about what it is, what causes it, and what vision with Strabismus would be like.
The first thing I found out was that the more common name for this disorder is crossed eyes, or wall-eyed. The text books definition of this disorder is "a misalignment of the two eyes, so that a single object in space is imaged on the fovea of one eye, and on a nonfoveal area of the other (turned) eye." According to a couple different websites, an easier way of understanding this is "a condition in which both eyes do not look at the same place at the same time". I know this may sound naive, but before doing any research on this topic when I heard the phrase cross eyed, I always thought it was just being able to turn your eyes in towards each other, or out and away from each other. I was not completely wrong, but I have learned that it isn't always something you can control right away.
It is estimated that approximately 5% of children have a varying severity of Strabismus. It will normally develop by the age of 3. Sometimes it may be easy to spot by looking at the children's eyes to see if they are looking in the same directions. Other times the child may complain of double vision. There is also the chance that the child has pseudostrabismus or false strabismus. This could be do to extra skin that covers the inner corner of the eye. The child will grow into it and then the false strabisums will disappear. It is important to recognize the symptoms of Strabismus so that appropriate treatment can be given to help reduce the damage on the visual system.
There are several different types of Strabismus. The most common/well-known being esotropia or the inward turning of the eye, exotropia or the outward turning of the eye, hypertropia or the upward turning of the eye, and hypotropia the downward turning of the eye.
There are a variety of things that could cause strabismus. A few of the most commonly believed causes are problems with the eye muscles, the nerves that transmit information to the muscles, or the control center in the brain that directs eye movements. As well as general health problems or previous eye injuries. There are other causes for each of the specific types of strabismus as well, some being prolonged farsightedness without treatment or correction.
There are four main treatments for strabismus. These are eyeglasses or contact lenses, prism lenses, vision therapy, and eye muscle therapy. Each of these treatments have their own pros and cons but I have found through most of my research that vision therapy seems to have the most recommendations.
I have included a link for a video series that I watched over this topic on youtube. It is a professor giving a lecture on strabismus and her experiences with the disorder. If this topic interests you at all, I would encourage you to watch at least the first part of the video (there are 3). She tells her story and what it is like to have something that messes with your vision.
http://www.aoa.org/x4700.xml
http://www.strabismus.org/
http://www.youtube.com/watch?v=aUzJogvB0Hc
*There is also a part 2 and part 3 to this video, however, they do not address much of Strabismus.
I guess I didn't catch that about being cross-eyed! That's really interesting to me. It makes me thankful that my eyes are normal for the most part!
I have known of many babies born with this condition. My cousin was one of them and she had to wear an eye patch. I am not sure how that helped but now her eye is fine. Very interesting to learn about.
I chose to further my knowledge on spatial frequency channels since I was a little confused on it when reading the chapter. The definition according to our text is; a pattern analyzer, implemented by an ensemble of cortical neurons, in which each set of neurons is tuned to a limited range of spatial frequencies. How we see today is explained by physical optics and retinal transduction, followed by feature detection, in the cortex, by a bank of parallel independent spatial-frequency-selective channels. There are three spatial frequency channels for hypothetical tuning curve. These include peak sensitivity of upper left grating, peak sensitivity of two right gratings, and peak sensitivity of lower left grating.
Furthermore, regardless of the distance from which a scene is viewed, images of naturally occurring scenes or objects (trees, rocks, bushes, etc.) tend to contain information at many different spatial scales, from very fine to very coarse. The textbook talks about the multiple spatial frequency model of vision which implies that spatial frequencies stimulate different pattern analyzers that will be detected independently, even if the different frequencies are combined in the same image. Gratings have four properties -- spatial frequency, contrast, orientation, and spatial phase. These properties are independent of one another, in the sense that any one of them can be changed without affecting the others. Orientation is pretty easy to grasp - it simply refers to the tilt of the grating: vertical, horizontal, oblique.
Spatial frequency" refers to the number of pairs of bars imaged within a given distance on the retina. One-third of a millimeter is a convenient unit of retinal distance because an image this size is said to subtend one degree of visual angle on the retina. To give an example, your index fingernail casts an image of this size when that nail is viewed at arm's length; a typical human thumb, not just the nail, but the entire width, casts an image about twice as big, two degrees of visual angle. The size (or visual angle) of the retinal image cast by some object depends on the distance of that object from the eye; as the distance between the eye and an object decreases, the object's image subtends a greater visual angle. The unit employed to express spatial frequency is the number of cycles that fall within one degree of visual angle (each cycle is one dark and one light bar). A grating of high spatial frequency -- many cycles within each degree of visual angle -- contains narrow bars. A grating of low spatial frequency -- few cycles within each degree of visual angle -- contains wide bars. Because spatial frequency is defined in terms of visual angle, a grating's spatial frequency changes with viewing distance. As this distance decreases, each bar casts a larger image; as a result, the grating's spatial frequency decreases as the distance decreases.
Example: An infant held on your lap will not be able to see fine spatial details visible to you. In this respect, the infant more closely resembles a cat. But unlike a cat, the infant does not have an advantage over you at low frequencies: you should be able to see everything that the infant can see. Also, even for spatial frequencies visible to both of you, the infant will require more contrast than you do. In a sense, these CSFs confirm what some parents have noticed: their very young infants seem oblivious to everything except very large, high-contrast objects. Incidentally, the lack of sensitivity to high frequencies does not stem from optical causes but from the fact that the infant's immature visual nervous system fails to encode high frequencies. In effect, infants are best suited for seeing objects located close to them (recall that spatial frequency is distance dependent), which makes sense from a behavioral standpoint.
Moreover, when it comes to the A B Cs, the alphabet's stroke frequency is defined as the average number of lines crossed by a slice through a letter, divided by the letter width. For sharp-edged (i.e. broadband) signals, we find that stroke frequency completely determines channel frequency, independent of alphabet, font, and size. Moreover, even though observers have multiple channels, they always use the same channel for the same signals, even after hundreds of trials, regardless of whether the noise is low-pass, high-pass, or all-pass. Stroke frequency completely determines channel frequency, independent of alphabet, font, and size. Moreover, even though observers have multiple channels, they always use the same channel for the same signals, even after hundreds of trials, regardless of whether the noise is low-pass, high-pass, or all-pass. This shows that observers identify letters through a single channel that is selected bottom-up, by the signal, not top-down by the observer.
http://www.youtube.com/watch?v=XaHZNBlXxiY
http://www.psy.vanderbilt.edu/courses/hon185/SpatialFrequency/SpatialFrequency.html
http://www.ncbi.nlm.nih.gov/pubmed/11997055
One of the topics I found the most interesting in chapter 3 was Robert Fantz's observation of infants' vision. Fantz observed that when infants have two objects in front of them, they will look at the object that is more complex. One example in the book was that if an infant was shown two pictures, one with stripes and one just a gray patch, the infant will prefer to look at the one with stripes. The catch, however, is that if the infant could not see the strips and could only see the gray picture, the infant would be equally likely to look at the gray picture as he would the striped picture. This is why preferential studies is an important method to study infants' vision. Another method to study infants' vision which has become more successful is by measuring VEPs, or visually evoked electrical potentials. This is done by placing electrodes on a baby's head and measuring the changes in activity when the picture or stimulus is changed.
I thought the topic of infant vision was very interesting, because I babysit a small child myself. One website stated that infants cannot see what adults see. Instead, their vision is blurry. The article stated that ciliary muscles automatically contract or relax the lens in the eye to help with focusing. In the first week of life, infants do not see very clearly. They have blurred vision and only see shades of gray. It takes several months for a baby's vision to mature to normal vision. This is because nerve cells in the baby's retina are not fully developed. They also have trouble focusing. This it because the ciliary muscles aren't as developed. What's interesting to me, however, it is shown that even a few days after birth, a baby prefers to look at the mother's face rather than a stranger's. After a week or so, a baby can start to see colors such as red, orange, yellow or green. It is harder for them to see purples and blues because the human eye has fewer color receptors in the retina. Blue also has shorter wavelengths as well.
It make take quite a while for an infant to be able to focus correctly. This is because it takes a while for infants to develop their visual acuity, or the ability to see detail. This relies on parts of the eye, but it also depends on the development of parts of the brain that help people to see detail. The part of the eye that helps with visual activity is called the fovea. I found all of this to be very interesting. I even came across a website that allows you to see what a baby can see at different ages and distances. It was very interesting!
http://www.ski.org/Vision/babyvision.html#are_black
http://www.allaboutvision.com/parents/infants.htm
http://tinyeyes.com/tinyeyes/tryit2.php
The topic that I would like to introduce about and get more information is infant vision. The textbook does not say a lot about this subject but there is bunch of stuff about in on Internet. One thing that our textbook introduces is that once we getting older, peak contrast sensitivity increases and it does shift toward higher spatial frequencies.
I found quit interesting website that talks about infant vision development. The author of the article says that when we get birth the most exciting first moment is when the child open his/her eyes and looks at us. Yet, that might not happen right away because the visual system of the newborn child has to develop with some time. The first look what the newborn have on world is in shades of gray and black and white color. Nerve cells in retina are not fully developed yet. They also don not have the ability to accommodate, so they cannot focus on near objects. Usually, it takes couple month to fully develop their vision. Studies showed that in the first couple days infants prefer looking at an image of their mother's face to that of a stranger. Also, interesting thing is that at birth the baby’s eyes are sixty five percent of their adult size.
Babe’s eyes are not very sensitive although the light detection threshold) is 50 times higher than that of an adult. After the first week of life they can see color such as red, orange, yellow and green, but it takes a bit longer for them to see blue and violet. It is because blue light has shorter wavelengths, and fewer color receptors exist in the human retina for blue light. Fully developed vision in babes is about six months old. Interesting study has been done on how and what babies can see. The researchers install a camera on the helm and put it on babe’s head. The video portrays the same thing what I read in the articles that babies do not look often at their mother’ faces, it is only about 15%. The babe was looking directly on the object that wanted to reach.
I wanted to know more about this topic just because having a better understanding what the babe can see can help me as a future mother and babysitter, open my eyes more open on their healthy childhood.
http://www.allaboutvision.com/parents/infants.htm
http://video.about.com/babyparenting/Understanding-infant-vision.htm
http://www.youtube.com/watch?v=aLWMFRvVed0
While reading the chapter I was interested in the lateral geniculate nucleus, so I decided to do some additional research into it. The lateral geniculate nucleus is the main processing center for visual information that is received from the retina. The lateral geniculate nucleus is located in the thalamus and is a part of out central nervous system. The LGN receives its information straight from ganglion cells in the retina through the optic tract; the LGN also receives feedback from the primary visual cortex. Our brain has a LGN for both the right and left hemisphere and the LGN consists of six layers which contain one million neurons; the first two being magnocellular layers which receive information from M gang lion cells, while the remaining layers are parvocellular layers and receive their input from P ganglion cells. The first two layers receive their information from the rods and are used in the perception of movement depth and difference is brightness; the response is quick, but is not sustained. The remaining layers receive their information from the cones and are used in the perception of color and form; the response is slow, but sustained. When the LGN gathers data is takes all the data from the left side of both eyes, then the right side, then from the bottom to the top.
Imagines to check out
http://en.wikipedia.org/wiki/File:ERP_-_optic_cabling.jpg
http://en.wikipedia.org/wiki/File:Gray683.png
http://upload.wikimedia.org/wikipedia/commons/c/c0/Gray722.png
Sources
http://www.ics.uci.edu/~majumder/vispercep/chap3_LGN_highvision.pdf
In chapter 3, I found the development of vision interesting. The book only discusses the development of spatial vision and contrast sensitivity so I decided to look up more information about other areas of vision and how they develop. Even in the embryo, a baby’s vision develops. They can tell the difference between light and dark. Right at birth, a baby can see shapes by following where light and dark areas meet. In the first few months of a baby’s life, they can only see things in black and white and shades of grey. They also have blurry vision and have trouble holding their gaze for more than a few seconds. Infants also haven’t completely learned how to use both eyes at the same time which can lead to crossed eyes but after a few months, this problem fixes itself.
After about four months, babies’ hand-eye coordination skills have improved greatly. They can also fully see in color – just as well as an adult. Sharpness of vision has also developed to 20/20 by six months. Between 6 and 8 months, babies develop their perception skills due to their ability to crawl and learn the relationship between their body and other objects. They’re also able to judge size, shape, and position easier. After 8 months, babies have developed visual memory and visual discrimination to help them learn and remember about the things that surround them. Although an infant’s vision will continue to develop and grow stronger, the first year is very important for growth of the ability to see and understand what they see.
http://www.childrensvision.com/development.htm
http://www.allaboutvision.com/parents/infants.htm
http://www.bausch.com/en_US/consumer/age/babies_eye_development.aspx
The Ch. 3 topic I am interested in is the condition called amblyopia. According to the book amblyopia is a develeopmental disorder that causes the person to have reduced spatial vision and acuity in one eye. It is often referred to as a "lazy eye". 3-6% of children under the age of 6 are believed to have a form of amblyopia. It is often diagnosed via a comprehensive eye exam and the use of cycloplegic drops (eye dilation). A theory suggests that if one of the child's eye is not seeing as well as the other, the better eye will develop stronger nerve connections and pathways than the other. The eyes compete with each other from birth to age 6 to develop connections and pathways to the visual cortex. The video I provided below suggests in order to potentially correct the problem you need to stunt (use a patch over) the better eye when the child is young (under the age of 6) in order to force the stronger eye to develop connections at a similar pace with the weaker eye. If the wiring connections are not fixed when a child is young then the amblyopia will remain uncorrectable. The most common causes of amblyopia are constant strabismus (constant turn of one eye), anisometropia (different vision/prescriptions in each eye), and/or blockage of an eye due to trauma, lid droop, etc. as stated in strabismus.org. According, to MedlinePlus there is often a family history of amblyopia.
In 2005 the National Institutes of Health sent out a press release stating that children over the age of 6 and up to the age of 17 can still benefit from amblyopia treatment. "Treatment (in their study they used an eye patch, medicated eye drops, and near vision activities) improved the vision of many of the 507 older children with amblyopia studied at 49 eye centers." Although there is hope for those who are diagnosed later in their childhood it is still very important for children to be screened before the age of 6 as it is the prime years to correct the problem.
In elementary school there was a girl that was older than myself who had strambismus and I also assume she had amblyopia. She had to wear an eye patch in order to correct her lazy eye. I felt really bad for her because she was constantly ridiculed by her classmates for something that she obviously could not help. It is amazing to me how we can correct for this when children are young and again it shows how our brain and vision can adapt if we work to correct it early enough.
http://www.youtube.com/watch?v=0kHCHvFhzWc
http://www.strabismus.org/amblyopia_lazy_eye.html
http://www.nlm.nih.gov/medlineplus/ency/article/001014.htm
http://www.nei.nih.gov/news/pressreleases/041105.asp
Nice video! It is crazy how simply covering up the dominant eye can help improve the eye with weaker vision.
The disorder I found interesting in Chapter 3 of the text was amblyopia which the author defines as a reduction in depth perception due to one eye perceiving the world from an incorrect angle. Having one eye pointed in the wrong direction is called strabismus, but if this disorder is present during a critical period of development in cannot be reversed and will develop in amblyopia. There are critical periods for many things in human development such as language development and ear development, but the period of development for the ocular nerves is the first 3 to 8 years of life. This loss of spatial vision is due to the face that the cortical neurons rewire themselves during the critical period to account for the misalignment, and that change cannot be reversed.
The original cause of the misalignment can be due to childhood cataracts, severe astigmatism, far sightedness, or near sightedness.
Available treatments (if detected early enough) include putting a patch over the working eye to force the lazy eye to work and speed up the correction process. This treatment must begin by at least 5 years of age to have any effect. If not corrected soon enough the only options are to wear corrective lenses. Doctors insist children with only one functioning eye wear shatter resistant glasses to avoid total blindness due to a future accident.
https://health.google.com/health/ref/Amblyopia
http://www.strabismus.org/amblyopia_lazy_eye.html
http://familydoctor.org/online/famdocen/home/children/parents/special/birth/460.html
I found the fact that there is a critical period of vision development to be particularly interesting. The author explains that if a child has a condition such as cataracts that causes them to see the world from a different angle and when that condition goes untreated beyond the critical period it is uncorrectable. It is very strange that even if what is physically wrong with the eye is corrected, the child will still not be able to see normally because the information the eye receives cannot be understood by the visual system in the brain. Apparently accommodation, muscle coordination, and ability to see in stereo are fully developed by the age of six months! It is currently recommended to have infants (even those with no apparent problems) first examination sometime before they turn two years old. This is because research suggests that the critical period of vision is at maximum two years of age. However, fairly recent studies on critical periods have challenged the predominant view on the phenomena. A fair amount of case studies have arisen recently of patients who were born blind developing sight far beyond the critical period raises some questions. After experiences with such cases some researchers at MIT are suggesting that perhaps acuity is subject to a critical period but other parts of vision are not. In fact these researchers were recently featured in an interesting article from Psychology Today. The group of researchers work is called Project Prokash and has provided evidence for the idea that blind children can see later in life (after cataract removal). When reading the book I found the critical period interesting but after further research I find it even more interesting. It feels somewhat overwhelming how much material there is to learn in these chapters, but these recent studies on the critical period of vision are evidence of how much more even experts have left to earn about the visual system.
http://www.strabismus.org/critical_period_Hubel.html
http://www.medicalnewstoday.com/articles/60249.php
http://www.psychologytoday.com/blog/you-illuminated/201011/can-blind-brain-learn-see
I find Ganglion cells to be particular interesting and complex, and am still trying to grasp the notion of on- and off- cells as well as our cortex cells. First, we cannot respond to any visual stimuli in our world with the help of individual ganglion cells. In class we learned, that ganglion cells compare the visual signals they receive to other ganglion cells. Furthermore, another function of the eye according to the article “Protecting Retinal Ganglion Cells: CFC Science Update” individual retinal ganglion cells change the light rays that enter the eye (picked up my the rods and cones) into electrical impulses and send them through the optic nerve to the brain(visual cortex) where images are perceived.
As the retinal ganglion cell has a center and a surround. If the light hits the center of the cell it will excite, and if it hits the surround it will be inhibitory. Furthermore if the whole cell does not fire and the surrounding cells do, the brain will interpret this as an edge. The axons leave the retina to the cortex, however there is a middle point between, the LGN. The LGN responds to form, motion, and color. Furthermore, it receives information from both eyes individually and starts to merge the visual fields according to “Struture of the visual system” website ran out of Waterloo University.
From there, information is sent to the primary visual cortex. In the book, the LGN includes the thalamus. I have always associated the thalamus with automatic movement and functioning, so it was interesting to learn it was so connected to our visual system. According to the website Buzzle.com the thalamus is in charge passing a lot of information on the brain like about sleep and alertness, as well as auditory and somatic systems.
The article “Visual Attention: The Thalamus at the Centre” talks about how the thalamus is correlated with both “fluctuations in visual attention and visual awareness”. The article states that our thalamus is probably very important in directly our visual attention. The axons connecting the thalamus to the brain pass through the thalamic reticular nucleus (TRN). The TRN formulates the small region of the topographically organizes thalamocortical maps through modulating LGN responses to visual stimuli. However, the website sciencedirect.com claims Topographic organization happens mainly in the visual cortex. In which perception visual stimuli are organized and put into coherent shapes. This area of larger system which sends information to areas in the temporal lobes that store visual memories to create a better idea of what we might be seeing
http://www.sciencedirect.com
http://www.glaucoma.org/research/protecting_reti.php
http://psychology.jrank.org/pages/1475/Mental-images-in-brain.html
http://www.ncbi.nlm.nih.gov/pubmed/19278639
When I read Chapter 3, I was really interested in levels of spatial frequencies and how high and low differed. I started snooping online and found articles about high and low spatial frequencies dealing with schizophrenic patients. I liked getting different views on the topic and how it effects different groups(babies and patients).
One of the experiments looked at the patients recognition of facial expressions and high and low frequencies compared to healthy participants. They found that the schizophrenic patients needed more definition of the faces to distinguish between expressions. It is harder for schizophrenics to identify facial emotions because they don't use their spatial frequencies like healthy people would. They use more low frequency more and is harder to comprehend high frequency. The other article I discovered discussed that schizophrenics have a malfunction in the right side of the brain that causes them to use lower frequencies. I also found an image that is an other example of different frequencies. I really liked the figures in the book about the different frequencies and wanted to find more. I think its interesting on the preference we have for images compared to patients with schizophrenia.
Sources:
http://dpss.psy.unipd.it/iclab/images/FRMF4.jpg
http://schizophreniabulletin.oxfordjournals.org/content/early/2010/02/15/schbul.sbq006.full
http://psycnet.apa.org.proxy.lib.uni.edu/index.cfm?fa=search.displayRecord&uid=2002-06065-009
I wanted to know more so I chose this as my topic.
The tilt aftereffect is the perceptual illusion of tilt, produced by adaptation to a pattern of a given orientation. There are many ways to test the tilt aftereffect and the staircase method is more efficient for estimating the threshold, because the level samples are adaptively clustered around the psychometric threshold. The psychometric threshold is usually unknown and a lot of data has to be collected at points on the psychometric function that provide little information about its shape. See How well you test with this method.
Look at me, Look at me...
http://jn.physiology.org/content/94/6/4038.full
We have been discussing how the beginnings of sight are on the retina since the beginning of the semester, but we know that parts in the brain are required to interpret the stimuli and create the image that we hold in our mind. An article from nature.com features a study in which scientists caused blindness in a sample of macaqua monkeys (the scientific name for these is MACACA MULATTA...ha ha) by cutting lesions into the primary visual cortex of the monkeys. Using fMRI techniques and behavioral observations they determined that the blind monkeys still were able to process some visual information. The article terms this "blindsight" (yes very imaginative) and holds that the structure responsible is the lateral geniculate nuclei. Basically the scientists exposed highly contrasted (in color and light) stimuli to the monkeys and witnessed a response in both behavioral terms as well as cortical activation. (observed using fMRI) When they inhibited the area of the thalamus known as the lateral geniculate nuclei (by injecting GABA-receptor-agonist-THIP) and exposed the monkey brains to the same stimuli the response was absent. This implies that at least some small level of practical processing occurs in the lateral geniculate. It would be an advantage evolutionarily. I mean the monkeys are blind but they can sense that highly contrasting stimuli are present, even if they cannot make out details. They probably don't even have any sort of mental image, they probably just have a vague unconscious sense that the lighting has changed or some shape has moved. But even this low level of sensation allows a blind monkey to survive. Change in light probably equals run. The lateral geniculate is attached to the part of the midbrain known as the thalamus. Although the midbrain is not cortex it still is involved with some processing that is represented in unconscious ways. For example our ability to access old and store new memories is affected by the amygdala and hippocampus and the amygdala is also responsible to the sudden change in bodily arousal as it initiates the sympathetic nervous system.
An article on a psych website (of laymen quality at best) describes a study that set out to investigate the architectural myth that a ceiling with a lighter color than the walls will appear higher than a ceiling with same colored walls. The psychologists found that although it did indeed appear that lighter ceilings were percieved as higher, the phenomena was not a function of contrast between wall and ceiling. Rather a lighter room in general was perceived as being taller. Perhaps this has something to do with what spatial frequency our receptors are tuned into. A lighter color is sending more light, more energy into our eye. Perhaps this increase in energy causes our receptive fields to be over stimulated and this exaggerates the height of the room.
I want to write more on this but I gotta go so I will post more later.
http://www.nature.com/nature/journal/v466/n7304/full/nature09179.html
http://www.physorg.com/news197550986.html
We have been discussing how the beginnings of sight are on the retina since the beginning of the semester, but we know that parts in the brain are required to interpret the stimuli and create the image that we hold in our mind. An article from nature.com features a study in which scientists caused blindness in a sample of macaqua monkeys (the scientific name for these is MACACA MULATTA...ha ha) by cutting lesions into the primary visual cortex of the monkeys. Using fMRI techniques and behavioral observations they determined that the blind monkeys still were able to process some visual information. The article terms this "blindsight" (yes very imaginative) and holds that the structure responsible is the lateral geniculate nuclei. Basically the scientists exposed highly contrasted (in color and light) stimuli to the monkeys and witnessed a response in both behavioral terms as well as cortical activation. (observed using fMRI) When they inhibited the area of the thalamus known as the lateral geniculate nuclei (by injecting GABA-receptor-agonist-THIP) and exposed the monkey brains to the same stimuli the response was absent. This implies that at least some small level of practical processing occurs in the lateral geniculate. It would be an advantage evolutionarily. I mean the monkeys are blind but they can sense that highly contrasting stimuli are present, even if they cannot make out details. They probably don't even have any sort of mental image, they probably just have a vague unconscious sense that the lighting has changed or some shape has moved. But even this low level of sensation allows a blind monkey to survive. Change in light probably equals run. The lateral geniculate is attached to the part of the midbrain known as the thalamus. Although the midbrain is not cortex it still is involved with some processing that is represented in unconscious ways. For example our ability to access old and store new memories is affected by the amygdala and hippocampus and the amygdala is also responsible to the sudden change in bodily arousal as it initiates the sympathetic nervous system.
An article on a psych website (of laymen quality at best) describes a study that set out to investigate the architectural myth that a ceiling with a lighter color than the walls will appear higher than a ceiling with same colored walls. The psychologists found that although it did indeed appear that lighter ceilings were percieved as higher, the phenomena was not a function of contrast between wall and ceiling. Rather a lighter room in general was perceived as being taller. Perhaps this has something to do with what spatial frequency our receptors are tuned into. A lighter color is sending more light, more energy into our eye. Perhaps this increase in energy causes our receptive fields to be over stimulated and this exaggerates the height of the room.
I want to write more on this but I gotta go so I will post more later.
http://www.nature.com/nature/journal/v466/n7304/full/nature09179.html
http://www.physorg.com/news197550986.html