What we would like you to do is to find a topic from this week's chapter 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 a video clip that demonstrates something related to the topic, etc. What you find and use is pretty much up to you at this point. Please be sure to use at least 3 quality resources. If you use videos, please limit it to one video.
Once you have completed your search and explorations we would like you to:
1a) State what your topic is.
1b) Discuss how the topic relates to the chapter.
1c) Discuss why you are interested in it.
2) Next, we would like you to take the information you read or viewed related to your topic, integrate/synthesize it, and then write about the topic in a knowledgeable manner. By integrating/synthesizing we mean taking what your read/experienced from the internet search 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 the information you have about the topic.
3) List the terms you used from the text and from your reference websites.
4) At the end of your post, please include working URLs for the three websites. For each URL you have listed indicate why you chose the site and the extent to which it contributed to your post.
1a. The topic that I have decided to do further research on is akinetopsia, a rare neuropsychological disorder that is characterized by the inability to perceive motion. It is often times an acquired deficit that results from antidepressants or trauma to the brain and it most frequently effects the medial temporal region of the brain.
b. This topic relates to chapter eight because it exemplifies the importance of motion perception and the consequence of damage to the part of the brain that is involved in perceiving motion. It goes into further detail explaining the motion parallax and the specific parts of the brain that are involved in visual processing. It also uses akinetopsia to present the effects of damaging the parts of the brain associated with motion as previous chapters do with other associated visual deficits.
c. I am interested in this topic because I think visual disturbances provide fascinating information about the parts of the brain that process motion perception. I am also interested in the causes of these deficits as well as treatment options that are available.
2. Zeki found that cerebral akinetopsia is a deficit that results in the specific inability to perceive visual motion following cortical lesions outside of the striate cortex. The recent discovery and acceptance of this deficit as a neuropsychological syndrome has influenced many studies on the qualities that make this disorder specific to movement perception. This research article explained the clinical definition of akinetopsia and the aspects of it that result in the loss of motion perception in humans. It is frequently the result of trauma to the brain from strokes or brain surgeries in the progress of healing. Patients who experience this loss of ability to perceive motion view the movement of objects as blurry pictures that appear and then reappear in a new place instead of the unfiltered instantaneous movement that we perceive without the presence of the disorder. Another article by Cooper et al. focused on two case studies of patients who suffered from akinetopsia for different reasons and experienced different outcomes as a result of the damage they experienced. The first individual was a woman who experienced sudden visual disturbance after experiencing a migraine located in the mid part of the brain. After a day or two of visual disturbance she realized while driving her vehicle that she was unable to perceive the movement of other cars and pedestrians. Instead of perceiving smooth movement she was only able to perceive broken up images that were freeze framed. The second individual was a man who suffered a left posterior hemispheric stroke resulting in issues detecting motion. This deficit became clear when the man realized that images presented in his right visual field did not move smoothly but instead jumped around as blurry images. These patients were some of the first to document their experiences with akinetropsia. The first patient exemplified the disorder as an isolated visual disturbance that effected the entire visual field while the second patient was an example of the visual disturbance being presented in only one visual field until the stroke symptoms subsided. Both of the case studies provided information about causes of of akinetropsia and aided researchers in discovering the location of motion perception in the brain. It also provided evidence to suggest that it is possible for the disorder to heal without medical intervention. Lastly, an article by Tsai et al. found a relationship between the presence of akinetropsia and alzheimer disease. Two case studies were done to assess the presence of the disorder as a variant of the development of alzheimers. The researchers found that both patients had akinetopsia located in the posterior cortical or visual variant that is correlated with alzheimer disease. This finding is very interesting because it finds a relationship between two horrible diseases that could result in new treatment options as well as new hypotheses regarding causes of the disorders. It also provides critical information about the location of the diseases in the brain and the important role they play in perceiving motion.
Research is still being performed to discover more details about akinetopsia and possible treatment options for patients that do not experience healing without medical intervention. There is also work being done to assess the parts of the brain that are involved with motion perception beyond the medial temporal lobe.
Terms: motion, perception, akinetopsia, medial temporal lobe, visual cortex, left posterior hemispheric stroke, Alzheimer disease
http://www.ncbi.nlm.nih.gov/pubmed/2043951 I chose to use this article because it gave a great description of akinetropsia and the appearance of it in the human brain.
http://web.a.ebscohost.com.proxy.lib.uni.edu/ehost/detail/detail?vid=3&sid=8c077944-a4a8-4510-bee6-bb6b19dbeb46%40sessionmgr4005&hid=4212&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=psyh&AN=2012-07138-024 I chose to use this research article because it gave examples of case studies that exemplified the result of damage from akinetropsia as well as the parts of the brain involved in these damaged areas. It also documented recovery from the disorder without medical intervention
http://web.b.ebscohost.com.proxy.lib.uni.edu/ehost/detail/detail?vid=5&sid=b0f1f0f3-87c9-4b5b-b998-470a2bd5e3e1%40sessionmgr111&hid=109&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=psyh&AN=2009-13335-014 I chose to use this article because it found an interesting connection between akinetropsia and Alzheimer disease as they relate to motion perception.
1a) State what your topic is.
Avoiding imminent collision by using time to collision, tau, and modern technology.
1b) Discuss how the topic relates to the chapter.
This topic relates to the chapter because it discusses estimating the time of collision and tau. Including a bit of technology information I thought would be beneficial.
1c) Discuss why you are interested in it.
This topic was interesting to me because I was curious to see what was the best estimator of imminent collision. I was also drawn to the topic to see if technology will someday be as responsive and accurate when predicting collisions.
In my first source, in 2012 a disastrous collision between three jets carrying 192 passengers was narrowly averted by the air traffic controller with only 1650 yards of separation between planes racing towards each other at speeds of 436 MPH. This near disaster highlights something that can be easily overlooked about our unconscious mind. Our brain constantly monitors ours surroundings automatically and acts to prevent collisions as we dodge obstacles in our path without giving it thought. Complex systems, special communication efforts, and certain protocols guard collision problems in transportation today. But effortlessly, our cerebral guidance system solves our little problem of possibly running into each other on the sidewalk. A study was done to observe two power walkers approaching a blind corner at the same time, variables such as behavior, change in speed or direction was not a factor. A reciprocal interaction between both people mattered the most, the mean predicted distance. If the MPD was less than 1 meter, both subjects altered course in a way to increase separation. If MPD was greater than 1 meter, neither person altered their stride. By mutually making a correction we avoid a collision.
My second source provides information on tau and TCC. As an object approaches, tau approximates the time to collision. Tau is defined as the inverse relative expansion rate of the objects image on the retina. Studies have shown that humans us TTC, but evidence for the use of TTC by tau remains inconclusive. This study presented observers with a visual of two sequentially approaching objects and observers were asked to compare their TTC’s when these objects vanished. Results showed that observers were most sensitive to TTC information and less sensitive to non-time variables such as distance to collision, speed, and object size. TTC specified by tau also weighted much more than TTC from distance and speed. So when other information is given, observers still use tau when making TTC judgments. In my eyes tau is an accurate unconscious strategy when estimating TTC, measuring tau in animals and humans would differ in my opinion. But when making TTC decisions, in all the different experiments in my source, tau always was favored.
My third source explains how car companies are utilizing technology. Ford, Honda and Volvo are rolling out the best technology in automotive technology to the prevention of an accident before it even happens. Automakers are installing pedestrian detection and braking systems in their new vehicle designs. Using special radars and cameras allows their vehicles, whether it be day or night, identify the pedestrian, warn the driver and usually brake in time. There is just one major problem, they like to use the word USUALLY so the technology always working and being reliable is still questionable. Will technology soon be able to react and make judgment calls as accurately as the human brain visualizes? You don’t really know, but then again having just the technology present might be a good thing to give drivers a “jump” I guess you could say before the accident arises. Technology seems to impress me more and more everyday, its incredible automakers and other tech gurus have the ability to manipulate actions you as a human only thought you were capable of.
https://www.psychologytoday.com/blog/the-new-brain/201208/avoiding-collisions-the-unconscious-mind-work
This source provided me with information on how accurate our unconscious mind avoids collision compared to transportation technology.
http://www.journalofvision.org/content/11/12/7.full
This source provided me with information on numerous studies backing the use of tau to estimate TTC. Therefore giving me reliable and credible information to personal support tau when estimating time to collision.
http://www.extremetech.com/extreme/192863-ford-and-honda-stop-collisions-before-they-happen-with-pedestrian-detection
This source has provided me with information on how technology has came so far in the automobile industry, and also how they are applying it. Avoiding collision is not only determined by the human nowadays, you car has a brain with vision too.
Terms: Time to collision, Tau
I choose to research Akinetopsia which was discussed in the end of this chapter. It prevents the perception of motion which is the prevalent topic of this chapter. I choose to research this because it looked interesting and made me think about how in movies they often do slow-mo shots that sound a lot like how some of these patients see normally, but as learned, they actually don’t see the in between parts, only the beginning spot and then end spot.
Akinetopsia , or motion blindness, is the inability to perceive the motion of objects. Typically these patients do not have a problem seeing objects that are not moving, nor do they have problems seeing color. Akinetopsia can be broken down into two different types based on severity and the way that motion is “seen” by the patients. Inconspicuous akinetopsia has been described as seeing an object move much like a cinema real would look. This is the less severe form, and the most common. Patients describe an after image affect when perceiving motion. Prescription drugs and HPPD, or hallucinogen persisting perception disorder, are two possible causes of this form of akinetopsia. The second kind of akinetopsia is Gross Akinetopsia. This form is quite rare and involves more severe symptoms of motion blindness. This form often affects the patient’s daily lives. A famous case of this form of akinetopsia is seen in a patient named LM. Her most famous description of her vision is “fluid appeared to be frozen, like a glacier”. This was in reference to pouring tea. LM was eventually able to make up for some of her deficiencies by training her hearing to estimate distances of things like moving cars. Another study that was investigated in my readings was that of an Asian man. He had a history of visual issues throughout his life beginning in his 40’s. He described his vision as “freeze frames in a motion picture”. In addition he said that while he could hear people talk fine, they appeared to be frozen in time. It was discovered that brain lesions and damage linked to epileptic seizures were the cause of this particular patients akinetopsia symptoms. He was given a drug called carbamazepine, which eliminated his symptoms. This is an exception however, because there is no known cause for this disorder as it is caused most commonly by brain lesions. However, if it is caused by things like drugs, the treatment is to quit the drugs, or to switch drugs. Further research has been found that by using transcranial magnetic stimulation, researchers are actually able to induce akinetopsia by stimulating the MT/V5 section of the brain. It has been determined that the middle temporal and mesial superior temporal areas of the brain have neurons in them which are sensitive to the direction and velocity of perceived objects. Therefore lesions in these areas may cause akinetopsia to appear. It has been found that Alzheimer’s patients have also been known to show symptoms of akinetopsia and the symptoms become worse as they experience mental decline.
http://en.wikipedia.org/wiki/Akinetopsia
this website was helpful in gaining a base knowledge about akinetopsia. It also mentioned the patient LM which I later read more about. In addition it talked about the different types of akinetopsia.
http://www.sciencedirect.com/science/article/pii/S2213323213000236
this one provided a case study which was nice to see a personal perspective. it also talked about being able to induce the disorder and the different lesions.
http://www.medscape.com/viewarticle/410860_6
this website was helpful in defining things in a really easy way to understand. the case study used some complex terms, but this website was really informative, but also easy to understand.
Terms Used: akinetopsia, gross akinetopsia, inconspicuous akinetopsia, motion blindness, HPPD, brain lesions, transcranial magnetic stimulation, MT/V5, middle temporal, mesial superior temporal, alzheimer
1a) State what your topic is.
The topic I chose to do research on is akinestopsia. Akinetopsia is a rare neuropsychological disorder in which the affected individual has no perception or motion. An individual is fully aware of the location shifts but they experience no perception of motion. It is caused by disruptions to cortical area MT. It is brought on by direct trauma to the area MT that is due to stroke or elective brain surgery. Patients in the latter category sometimes regain normal motion perception abilities several weeks after surgery indicating the human brain can sometimes rearrange its connections so that different areas take over the MT’s motion-processing functions.
1b) Discuss how the topic relates to the chapter.
This topic relates to the chapter because it talks about the importance of motion perception and the consequences of brain damage to that part of the brain. It goes into detail explaining the motion parallax and the specific parts of the brain that are involved in visual processing. It uses akinetopsia to demonstrate the effects of damaging the parts of the brain associated with motion.
1c) Discuss why you are interested in it.
I’m interested in this topic because I think it’s interesting that people have this sort of problem. It’s hard for me to picture how they see without motion. I’m also interested to know if there are treatments with this since some people aren’t lucky enough to regain normal motion perception.
I found a research article about a patient that had developed motion blindness after brain lesions. Although she was capable of seeing stationary objects, her perception of moving objects was impaired. Other than minor difficulties with naming objects, her impairment was limited to an inability to perceive motion. Instead of perceiving fluid motion, she saw objects appear at various locations along with trajectories.
For the experiment they first established a normal visual function on stationary targets. Visual acuity, binocular vision, stereopsis, foveal color discrimination, and recognition of shape stimuli and words were near normal and didn’t indicate any deficit. They also tested various moving stimuli. With a movie spot of light in the favea, the patient had slightly better perception when allowed to track the stimulus instead of fixating at a central point. Generally she could see slow movement, but could not at faster speeds. In her peripheral vision she was unable to distinguish either direction or speed of motion. She was unable to notice any motion in depth of a cube moved toward or away from her. She also did not perceive motion effects of apparent motion. Tactile and acoustic motion perception were found to be normal.
With visual pursuit eye movements, the patient could smoothly track at lower speeds but could not at higher speeds without her eyes jumping. The researchers could then conclude that movement vision is processed separately from primary vision because there was no impairment with stationary or non-visual stimuli. The region responsible for motion perception has been identified as V5. The temporary motion blindness can be induced by TMS over V5. Currently there are no known treatments for the problem. The patient in this case though was able to distinguish human movements when lights are attached to joints of a person in the dark.
Another article I found focused on two case studies of patients who suffered from akinetopsia for different reasons and experienced different outcomes as a result of the damage they experienced. The first individual experienced a sudden visual disturbance after experiencing a migraine located in the mid part of the brain. After a couple of days she realized while driving she was unable to perceive the movement of other cars and pedestrians. She was only able to perceive broken up images that were freeze framed. The second individual suffered a left posterior hemispheric stroke resulting in issues detecting motion. This deficit was clear when the man realized that images presented in his right visual field didn’t move smoothly but jumped around as blurry images. These findings are important because it aided researchers in discovering the location of motion perception in the brain. Research is still being performed to discover more details about akinetopsia and the possible treatment options for those patients that do not experience healing without medical intervention. There is more work being done now to assess the parts of the brain involved with motion perception beyond the medial temporal lobe.
Terms: perception, motion, akinestopsia, neuropsychological, cortical area, MT, stroke, elective brain surgery, motion-processing, functions, stationary targets, visual acuity, binocular vision, stereopsis, foveal color discrimination, shape stimuli, deficit, stimuli, peripheral vision, depth, tactile, acoustic motion, primary vision, impairment, non-visual stimuli, medial temporal lobe,
URL: http://kevinleung.com/archives/akinetopsia/
URL: http://www.ncbi.nlm.nih.gov/pubmed/2043951
URL: http://web.a.ebscohost.com.proxy.lib.uni.edu/ehost/detail/detail?vid=3&sid=8c077944-a4a8-4510-bee6-bb6b19dbeb46%40sessionmgr4005&hid=4212&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=psyh&AN=2012-07138-024
The reason I chose these websites was because there wasn’t a lot of general information on the topic. There was a visual for one website but the rest I were able to find were research articles. The articles had interesting research experiments on the topic though.
The topic I chose to research further is akinetopsia. Akinetopsia is a rare neuropsychological disorder in which an individual has lost all ability to perceive motion. What is interesting is the fact that the affected individual is aware of location shifts but they don’t actually experience the perception of motion. Akinetopsia is often times an acquired condition that results from excess strain to the brain or from taking medication such as antidepressants.
Akinetopsia relates to chapter eight and sensation and perception because this chapter talks about how important motion perception is. This chapter goes into detail explaining the motion parallax and different parts of the brain involved in visual processing. I am interested in this topic because many disorders attract my attention. I have always been interested in ailments and disorders because they are most of the time they are unusual. Unusual things have always been interesting to me because they involve thought beyond the norm. Everyone can look at something and find it to be normal but I am one to look further into the details and find the abnormality involved. I also find this interesting because I find it hard to imagine what these individuals with this disorder see every day. How can one see without the sense of motion? I have many questions I hope to find answers to.
There are different signs and symptoms that I read about when researching this topic. Akinetopsia can be separated into two separate categories. These categories are divided by symptom severity and the amount the akinetopsia affects the patient’s quality of life. The first category is called inconspicuous akinetopsia which is also the most common kind of akinetopsia. This form of the disorder is described as seeing a multiple exposure photograph. Then there is the form called gross akinetopia which is an extremely rare condition. This is when individuals with this disorder have profound motion blindness and struggle in performing day to day activities. This case can be so extreme that affected individuals have trouble following conversations due to the lip movements and changing facial expressions. One way to cope with this extreme of a case is to train hearing to accommodate the lack of motion perception.
I mentioned a few causes of akinetopsia previously in my findings but there are many others. A few of these include brain lesions, transcranial magnetic stimulation, and Alzheimer’s disease. Akinetopsia may be an acquired deficit from lesions found in the posterior side of the visual cortex. Neurons of the middle temporal cortex respond to moving stimuli and the middle temporal cortex is also the motion processing area of the cerebral cortex. There has not been much research on Alzheimer’s disease leading to akinetopsia but some findings show that these patients may have varying degrees of this disorder. Antidepressants can result in a lot of different side effects, akinetopsia being one of them. If one takes their medication in high doses for long periods of time, the outcome can be bad. What is good is the point that normal vision can return once the antidepressants are not being taken in such large doses.
Upon research, I found one study that really caught my eye. This patient is a 43 year old female who in this study is called LM who was admitted to the hospital due to headaches and vertigo. LM was later diagnosed with brain lesions of the visual cortex. She had minimal motion perception but found no effective treatment. LM eventually learned to cope with this disorder by avoiding conditions with multiple visual motion stimuli. This means that she would make an effort to not stare of fixate on them. LM taught herself to estimate the distance of moving vehicles by means of sound detection in order to cross the street and for other uses as well. After further testing, LM was found to have no restriction in her visual field and no scotoma. This study was interesting to read about because the results gave the researchers so many findings to report. I found a few case studies while researching akinetopsia. I chose to share the study done over LM because I found the most information from that study, and it is also known to be a breakthrough to the study of akinetopsia.
Terms: Sensation, perception, akinetopsia, motion, medial temporal cortex, Alzheimer disease, visual field, scotoma, posterior, inconspicuous akinetopsia, gross akinetopsia, disorder, sound detection, neuron, visual cortex, motion blindness, neuropsychological.
URL: http://en.wikipedia.org/wiki/Akinetopsia - I chose to use this website because it gives me general answers to what akinetopsia is and other facts about it.
URL: https://www.youtube.com/watch?v=B47Js1MtT4w – I watched this video and I enjoyed it because it talked about the study done over the 43 year old woman I mentioned and it gave me even more detail than what Wikipedia did.
URL: http://web.a.ebscohost.com.proxy.lib.uni.edu/ehost/detail/detail?sid=f909eef1-44b5-4af1-974d-488d14943213%40sessionmgr4002&vid=0&hid=4107&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=psyh&AN=2009-13335-014 – I always find these articles to be extremely valid so I never have to wonder if I am using a reliable source. I enjoyed reading through this article because it gave me insight to two more case studies that turned out to be very interesting. Having read this information, I knew I was looking at factual information from the other two sources.
1a) The topic I chose to write about was apparent motion.
1b) Apparent motion is related to chapter 8 because the topic of chapter 8 is specifically about the perception of motion. Apparent motion is a type of optical illusion that connects strongly with motion perception. It could be considered a glitch in our perception of smooth motion.
1c) I am interested in apparent motion because I find optical illusions fairly interesting. It seems rather interesting that a system as advanced as the human brain can be fooled into seeing things that aren’t there, or fill in gaps in our vision. Apparent motion fits into both of these categories. I also find apparent motion interesting because it is the basis for many of my favorite childhood movies. Without the concept or existence of apparent motion, many cartoons and Disney movies would not be animated in the same manner. Without apparent motion, our childhoods may very well have looked much different.
2.) Apparent motion is a visual illusion where a smooth, continuous movement is perceived between two or more images. These images will have the same subject matter, but certain objects in the image will have different and changed placements. These placements must not be too far apart, or the illusion will be lost. When the images are viewed in rapid succession, the brain must overcome the correspondence problem. This means that the brain must decide which points on the first image correspond to which points on the next image. When the brain is able to do this, the objects in the set of images will appear to move smoothly, similar to real life. According to the text, the first recorded demonstration of this phenomenon was by Sigmund Exner in 1875. He had shown two sparks on a self-made device that appeared to be a single moving spark. Renowned psychologist, Max Wertheimer, also noted apparent motion in the early 1900’s. This finding eventually led to apparent motion being a large part of Gestalt Psychology. Wertheimer coined the term, “phi phenomenon” to describe the apparent smooth motion between two motionless objects when viewed in fast succession, otherwise known as apparent motion.
It is no question that apparent motion is an interesting optical illusion. However, is there a reason for this phenomenon? Some theories say that there is. According to one particular theory, apparent motion is perceived in early visual processing stages acquired through the long process of human evolution. This utilitarian theory of perception suggests that our visual system created “short cuts” in our visual perception in order to better adapt us for the environment around us. Imagine an ancient human searching in the forest for food. During this search, it is necessary for that human to look for any movement. This movement could signal a potential prey or a potential predator. In this theory, humans developed this visual shortcut in order to piece together movements when a moving object may disappear behind a bush, tree, or other obstacle. In doing so, we are better able to perceive a moving object faster and we are able to more quickly decide a proper course of action.
In modern times, apparent motion is used in many facets. An early form of animation is based in the concept of apparent motion. For example, “flip-book” animation is a prime example. This is where an object, such as a ball, is drawn on many pages of a flip-book (like a post-it pad). On each page, the ball will be in a slightly different location. As you flip through the book, you will see the ball appear to move smoothly over the pages. Apparent motion is also used in many neon signs in order to attract attention. One of these from my own personal experience is a convenience store sign with a horse with two sets of legs. When the lights on the legs light on and off opposite each other, the horse appears to gallop. All in all, apparent motion is an optical illusion, which has many uses, both practical and enjoyable.
http://www.britannica.com/EBchecked/topic/395223/movement-perception/46631/Apparent-movement
I liked this source because it was a simple, baseline source of information. This allowed me to gain a basic understanding of the material before moving on to other, more elaborate sources.
http://chip.ucsd.edu/pdf/Percpt_Apprnt_Mot_Sci_Am.pdf
I chose this source because it was a very in depth article that provided a lot of great information. It offered an explanation for this illusion that I had a great deal of trouble finding elsewhere.
http://webspace.ship.edu/cgboer/gestalt.html
I picked this source because it offered information on some of the history of apparent motion. I enjoy knowing how something came to be. Knowing that often gives one a better understanding of the topic as a whole in my experience.
Sensation and Perception Text Book:
I just liked the information in the book, so I used some of that in the essay.
Terms: apparent motion; visual illusion; Gestalt; Psychology; Phi Phenomenon; visual processing; correspondence problem, optical illusion, motion, utilitarian theory of perception; motion;
This week for my topical blog I chose to look further Akinetopsia. Akinetopsia is a neurological disorder which is also known as motion blindness. Akinetopsia is a syndrome in which a patient loses specifically the ability to perceive visual. This topic relates to chapter eight because this chapter is focused on motion perception and its importance within our senses. Chapter eight also goes into talking about further explaining the specific parts of the brain that are involved with visual processing. Akinetopsia is used in the chapter to present the effects of damaging parts of the brain associated with motion. I choose to research this because I work with an individual who is most of the way blind and since I have started working with him the eyes and their ability’s in our daily life is something that I have personally found interesting. As I have been working with an individual with a visual disability I find it fascinating to see just how our body’s are able to change and adapt without one of our main senses that we feel that we need on a daily basis to function a “normal” daily life. With working with someone with a visual disability I often wonder what it would be like to adapt to the world after being able to see at one time. It made me think of what if we weren’t able to see objects move right in front of us, would we live our lives differently.
Cerebral Akinetopsia is a neuropsychological disorder in which a patient is unable to perceive motion in their visual field even though they are able to see stationary objects with no issue. This disorder is caused by a lesion in area V5 of the extrastriate cortex. It can also be caused as a side effect of antidepressant drugs, or damage a stroke or certain brain surgeries. Akinetopsia can be separated into two categories based of the symptom severity and an amount that it affects the patient’s quality of life. The first category is Inconspicuous Akinetopsia which is often described by seeing motion as a cinema reel, this is the most common kind of Akinetopsia and many patients consider the stroboscopic vision as a nuisance. This is often caused by prescription drugs, hallucinogen persisting perception disorder. The pathophysiology of Akinetopsia is not known but has been hypothesized to be due to inappropriate activation of physiological motion suppression mechanisms. The second category is gross Akinetopsia which is an extremely rare condition. Patients have profound motion blindness and struggle to perform activities of daily living. These patients have a change in brain structure disturbs the psychological process of understanding sensory information which for this case would be the visual information.
When going through the different webpages I often seen them reference a specific case with patient LM. LM was a 43 year old female that suffered from a stroke, and latter LM described to her doctor the symptoms of Akinetopsia. LM went to the hospital after having sever migraines for a few days, this was at which time the doctors told LM that a stroke had taken place. After a few days she noticed while she was driving that she was not able to perceive the movement of the cars driving around her and noticed that they often appeared frozen in front of her. MRI scans showed the area of the brain which made LM visual perception deficits. I found it particularly interesting to watch the video that had patient LM comments along with the doctors. LM was not able to perform many daily tasks that went on throughout her life like pouring a cup of tea as the liquid would be “frozen” into place and the cup would often overfill. Another example was that he would not be able to see people come and go from a room they would just often appear in front of her with no explanation as to how they got there. One thing that I found very scary was the uncertainty to be able to cross the street as the person would not be able to tell where the car was and how close the car actually was to the individual.
http://en.wikipedia.org/wiki/Akinetopsia this webpage gave me the most knowledge about the topic as I was reading. It also mentioned LM which I later read an article and watched a video about so it made it easier to understand.
http://www.medical-library.net/content/view/1694/41/ this webpage gave me more medical information that was not in the book and more about the different causes of the disorder.
http://mooreperceptionproject.weebly.com/patient-lm.html this webpage gave an inside information about a patient and how their real life experiences and how they were affected by the disorder. I found her personal opinions very interesting.
Terms: Akinetopsia, gross Akinetopsia, inconspicuous Akinetopsia, motion blindness, motion perception, neuropsychological, area V5, extrastriate cortex,
1a) Cochlear implants
1b) The chapter talks about how the cochlea works and towards the end of the chapter cochlear implants were briefly talked about.
1c) Cochlear implants are interesting because I think using a microphone to listen to the environment and converting the sound to its frequencies and stimulating the correct area on the basilar membrane is an amazing, almost futuristic innovation to medicine.
2) The cochlea is where the sound vibrations are translated into neural signals. The happens specifically on the cochlear partition. Sound vibrations are sent down the base of the cochlea using the tympanic membrane, the ossicles and the oval membrane. The sound wave physical bulges down the vestibular canal from the base to the apex. This vibration wave or “bulge” stimulates a structure called the organ of Corti which contains specialized neurons called hair cells. These sensory neurons extend all the way down the cochlea on the basilar membrane. The length of the basilar membrane is specially tuned for certain frequencies. At the base high frequencies stimulate the hair cells and when you move down to the apex lower and lower frequencies stimulate neurons. This is where I think the innovation of cochlear implants are cool. If you integrate the idea of specific nerve energies you can digitally create and perception of hearing. Instead on using the middle and outer ear structures we can use an implant that will electrically stimulate the correct area of the basilar membrane. In medical cases where a patient loses their ability to hear there is a chance that this procedure might help. A microphone is then used to interpret surrounding sounds and translates it to stimulate the correct regions in the cochlea as the normal sound wave or “bulge” would. This mimicry of hearing is inspirational to me. It makes me wonder how many sensory organs can be synthesized and integrated with the body. The textbook says that there are 24 electrodes on the implant as of today. In Australian scientist announced a “hi-fi” implant with 50 electrodes. This increase in electrodes will increase the clarity of the perception of hearing and making the increase the overall experience. It is hoped with this increase that the users will be able to perceive music and pick up multiple voices in a noisy room. If that doesn’t inspire you, I don’t know what would. We take hearing for granted as it is. Imagine a world without music!?! Now imagine giving that world to someone with hearing loss.
Terms: Cochlear implants, cochlea, frequencies, tympanic membrane, ossicles, oval membrane, organ of Corti, hair cells, basilar membrane, specific nerve energies
Sources:
Textbook
http://en.wikipedia.org/wiki/Law_of_specific_nerve_energies
http://en.wikipedia.org/wiki/Cochlear_implant
Wikipedia is a great place to get a good sense of the background of the subject
http://www.mayoclinic.org/tests-procedures/cochlear-implants/care-at-mayo-clinic/treatment/PRC-20021470/?wt.adtype=s&wt.mc_id=us&campaign=mcr_ent&geo=regional&kw=%2Bcochlear%20%2Bimplant&ad=28202750556&Network=googleSearch&SiteTarget=&account=2818104325&gclid=CjwKEAjwz_-nBRC0zbDb_YOT1TgSJACW2VECVDs3qBM2razIgl3bZOO-UDUSOqXAGdMHj3A1oVvFTRoChV7w_wcB
Mayo clinic site helped me understand what medical cases cochlear implants could be used for and how the procedure is done.
http://www.nidcd.nih.gov/health/hearing/pages/coch.aspx#e
Had a few words on the future of cochlear implants
The topic I have chosen to research is akinetopsia.
This topic relates to the chapter, because it talks about the importance of motion perception and the consequences of brain damage to that part of the brain. It goes into detail explaining the motion parallax and the specific parts of the brain that are involved in visual processing. It uses akinetopsia to demonstrate the effects of damaging the parts of the brain associated with motion.
I am interested in the topic, because I cannot imagine living with this disorder. It seems quite apparent that anyone living with this disorder would find even the simplest tasks to be very daunting.
Akinetopsia, also known as motion blindness, is a neuropsychological disorder where one cannot perceive motion in one's visual field even if one is able to see stationary objects without any issue. The disorder varies in degrees from seeing motion as a sort of stop motion movie to the complete inability to discriminate any motion. The varying degrees are separated into two categories: inconspicuous akinetopsia and gross akinetopsia. Inconspicuous akinetopsia is often described by seeing motion as a movie reel or a multiple exposure photo. This is the most common kind of the disorder and many patients consider the stroboscopic vision to be quite annoying. This is often seen as visual trailing in the visual field with afterimages being left at each frame of the motion. This type of akinetopsia is caused by prescription drugs, hallucinogen persisting perception disorder (HPPD), and persistent aura without infarction. The actual pathophysiology is not known, but it is believed to be due to inappropriate activation of physiological motion suppression mechanisms which are normally used to maintain visual stability during eye movements. Contrary to inconspicuous akinetopsia, gross akinetopsia is an extremely rare condition. Patients with this form of the disorder suffer from profound motion blindness and struggle in performing even the simplest daily activities. Instead of seeing vision as a movie reel, patients have trouble perceiving gross motion. Most of what is known about this condition was learned through a specific case study of patient LM. She described the easiest tasks as being almost impossible. For example, she could not poor drinks into cups "...because the fluid appeared to be frozen like a glacier." Because of this, she did not know when to stop pouring and often caused the cup to overflow. She also found it quite difficult to follow conversations, because lip movements and changing facial expressions were missed. Patient LM had even greater difficulty when more than two people were moving in the same room. She described it as, "...people were suddenly here or there, but I have not seem them moving." She even had to train her hearing to estimate distance for situations like crossing the street, because she was unable to discern the distance of oncoming traffic. A change in brain structure, usually lesions, disturbs the psychological process of understanding sensory information, such as visual information in this case. Disturbance of only visual motion is possible due to the anatomical separation of visual motion processing from other functions. People with akinetopsia can still perceive spatial acuity, flicker detection, stereo and color vision, and identification of shapes, objects, and faces. This disorder also shows that when doing visuomotor tasks like reaching for or catching objects, feedback of one's own motion appears to be important, because of the apparent difficulty in affected patients.
There are four main causes for akinetopsia: brain lesions, transcranial magnetic stimulation, Alzheimer's disease, and antidepressants. In the case of brain lesions, the disorder may be an acquired deficit from lesions in the posterior side of the visual cortex. Lesions are more likely to cause gross akinetopsia rather than inconspicuous akinetopsia. Inconspicuous akinetopsia can also be selectively and temporarily induced using transcranial magnetic stimulation of area V5 of the visual cortex in healthy subjects. While little research has been done on the subject, there is evidence suggesting a link between Alzheimer's disease and this disorder. This could contribute very highly to the marked disorientation seen in Alzheimer's patients. Certain antidepressants may trigger inconspicuous akinetopsia in high doses with vision returning to normal once the dosage is reduced.
http://en.wikipedia.org/wiki/Akinetopsia - I used this source, because it provided a lot of detailed information on many aspects of the disorder.
http://mooreperceptionproject.weebly.com/patient-lm.html - I used this source, because it went into great detail about a specific case study that provided much of the current knowledge base on the subject.
http://www.allpsych.uni-giessen.de/karl/teach/SemVisNeuro/Zeki1991.pdf - I used this source, because it provided a lot of information on the topic and appeared to be a very credible source since it is a published paper.
Terms: Akinetopsia, Visual Processing, Motion Blindness, Brain Damage, Inconspicuous Akinetopsia, Gross Akinetopsia, Stroboscopic Vision, Visual Trailing, Lesions, Sensory Information, Transcranial Magnetic Stimulation, Visual Cortex,
1.A) Akinetopsia
B) This topic is related to the chapter because it has to deal with motion which is what the chapter is all about.
C) I am interested in it because I wanted to find out if it was treatable and how people could cope.
2.
Akinetopsia is also known as motion blindness. It is a very rare neuropsychological disorder. This disorder is between the nervous system and mental functions. Someone with this is unable to perceive motion. They will only see still images and only when objects are still will it be normal for them.
First, light is reflected into the retina and it gives sight and then it's an image by the occipital lobe. Then to see a motion the retina scans images. Movements are called saccades and between those movements eye movements are linked and then is perceived as a motion. If the visual cortex is damaged this won't happen and it will only see still images. A few examples of things people with this disorder will not be able to see are flags waving in the wind and a person riding a bike.
There are many symptoms and they include frequent headaches, the "strobe light" effect, fear of vehicles/crossing the street, fear of dogs, feelings of vertigo, difficulty having conversations, unable to enjoy movies, difficulty pouring liquids, and unable to perceive illusion of apparent motion. There fear of vehicles and crossing the street comes from being unable to watch the vehicles moving, but they can judge the distance. They are afraid of dogs because of their quick motions and they are unable to perceive their motions. Sometimes they may feel dizzy and sick from having rapid appearances and things disappearing. They see the world in frames with gaps but they do not connect motion.
One of the causes is by a lesion in area V5 of the extrastriate cortex. It can also be a side effect of atindepressantsor damage by a stroke or brain surgery. Some treatments are brain surgery or stop taking antidepressants.
http://mooreperceptionproject.weebly.com/symptoms.html
This site was useful because it listed many symptoms.
https://www.youtube.com/watch?v=tYFhDzQ1rYU
This video was useful because it showed and example of how someone with this disoder would see things and it also explained the process of motion.
http://www.medical-library.net/content/view/1694/41/
This site was useful because it explained the causes and treatments of this disorder.
Terms: Perception, area V5, extrastriate cortex, saccades, motion, visual cortex, retina, occipital lobe.
1. The topic I picked to explore is eye tracking. This topic relates to chapter 8 because it is a type of motion perception the eye does every day. I am interested in this topic because the book talked about how we use eye movements while reading, so I wondered if what other factors impact reading. I wondered if there were any other situations where we used eye tracking when we weren’t trying to read something. .
2. Eye tracking is a specific type of eye movement. When eye tracking is applied to reading, it uses visual processing to understand the written text. Louis Émile Javal discovered that when a reader was reading a line of text, the reader’s eyes did not read the line in a smooth fashion. The reader’s eyes instead jump over words and only focus (short stops) on the longer words. This is called saccades, and the shorts stops are called fixations. This is a relatively new concept as Javal only came up with the concept late in the 1800s. Amazingly, this concept is still considered correct today as the only technology Javal had available to him at the time he discovered this was simple naked-eye observation. Despite the fact he only watched the eyes of the reader, when new technology (infrared tracking, and computer technology for example) was later introduced his theory still held water.
While I did not find any research on eye tracking within any specific wring direction, I did find a lot of research done on eye tracking within one language that is read left to right horizontal. I was surprised to know that there are 8 different directions around the world writing systems use. A lot of the research I found focuses on English, not that I am saying that no research has been done on the other directions. The type of reading being done is
I found that when a reader is doing silent reading, their eyes tended to have an average fixation time of 250 milliseconds before jumping to the next fixation point. . But the fixation stop could be as short as 100 milliseconds and as long as 500 milliseconds depending on the difficultly (defined as low frequency/ unfamiliar words) of the specific word. If the world in question is very difficult there might even have to be a second fixation in order to correctly process (aka encode) that word. Oral Reading tends to have even longer fixation points because it takes longer to take in word and process those words so they can be read out loud. This happens automatically but that is a good thing. It is a good thing because the brain needs to give eyes a break. The eyes of People who are reading out loud also tend to focus longer (pause) so the brain can give the voice the chance to catch up with the eyes. I also found out that the words most likely to be focused on are content words, mainly verbs and nouns.
But what about the words not in the foveal fixation zone, you ask. The words not covered by the fixation points are not skipped in the strictest sense of the definition. It would be better to referee to them as skimmed because the brain doesn’t need to focus on them since they are so simple. Words like “the”, “and”, “well” are examples of words that are encoded while not in the fixation point because they are processed at the same time.
Passing a car on a two-way road also uses the eyes ability to track as the driver has to pay attention to the lane they are sharing with oncoming cars, as well as when it is safe to move into to the lane where they are going the same direction as the other cars. This example proves how expense increases the chances of safely moving around in the world with ease. Inexperienced drivers tended to focus on the space direction in front of their car and the space they needed to move into even though the two spaces are not next to each other. While experienced drivers learned it was sifter and easier to focus further ahead of their car because they needed to pay attention to the road further up and the spot they wanted to move into. This is an example of eye tracking in the real world.
3. Terms: eye tracking, motion perception , eye movements, visual processing , eye, short stops, saccades, fixations, naked-eye observation, infrared tracking, computer technology , writing direction, left to right horizontal, writing systems , reading, fixation time , low frequency/ unfamiliar , second fixation , process, encode, Oral Reading, voice, words,, verbs, nouns, foveal fixation zone, skimmed.
4. Sources
http://en.wikipedia.org/wiki/Eye_movement_in_reading. I picked this site because it is correct and easy to understand. I used it for: the basic information on eye tracking in reading,
http://www.omniglot.com/writing/direction.htm#ltrv I picked this site because it was easy to understand and showed examples of writing directions. I used it for the bit on wring direction.
https://www.youtube.com/watch?v=zQmf5TkJrJ8 I picked this video because it quickly explained the differences in average speed of type of reading. I used it for the differences between oral and silent reading.
http://www.readingrockets.org/article/eye-movements-and-reading. I picked this site because it had the part about content words. I used the part about content words (verbs and nouns).
http://en.wikipedia.org/wiki/Eye_tracking I picked this site because it is correct and easy to understand. I used it for the bit about cars passing because it talked about how experience is very important when talking about eye tracking.
For this week’s assignment, I chose to do more research on akinetopsia. Akinetopsia is defined as a neuropsychological disorder in which a patient cannot perceive motion in his or her visual field, despite being able to see stationary objects without issue. Other names of this disorder are cerebral akinetopsia or motion blindness. This topic fits in with our chapter because it is mentioned in our text book. The reason I took interest in this topic is because I am interested in more of the unusualness or disorders when I read technical studies.
The process of visual motion begins at the retina, where it is handled primarily by cells of the "magnocellular pathway." These cells send motion information to primary visual cortex via the lateral geniculate nucleus of the thalamus. Motion processing continues in cortex through several visual areas, ending up eventually in a region of temporal cortex called MT. Cells in MT respond to sophisticated aspects of motion, including motion in 3D and motion of animals. As is typical, the visual cortex of the left hemisphere of the brain processes information for the right visual field, and the right hemisphere processes the left visual field. A stroke to area MT in the left hemisphere can therefore impair the perception of motion in the right visual field, a condition known as hemi-akinetopsia. A patient suffering from hemi-akinetopsia has normal motion perception in one half, say the left half, of the visual field, but cannot see motion in the right half of the visual field. Instead, such a patient reports seeing the right half of the visual field as though it were viewed with a strobe light.
Changing of the brain’s structure, often caused by lesions, agitates the psychological process of understanding sensory information. This is possible, because the visual motion processing area of the brain is anatomically separated from other functions. There isn’t very much research done on this disorder. Many of the websites visited, talk of person they called LM. After many years of studying LM, they came to the conclusion, that after her stroke, there was damage done to the area between her temporal lobe and her occipital lobe. Much of what is known of the disorder comes from studying one specific patient with the disorder known as LM. People with Akinetopsia can still see color, spatial acuity, and flicker detection. The disorder affects the ability to reaching out to objects and catching objects. The brain actually sees things in snapshots, instead of in fluid motion. Pouring a cup of coffee is deemed difficult, because the sufferer cannot see when to stop pouring. The coffee appears to be frozen. Another aspect I did not see would be difficult is conversations. The sufferer cannot see facial expressions changing during the conversation or lips moving. The disorder is extremely rare and there is currently no effective treatment or cure for the disorder.
Testing of akinetopsia or “Motion Blindness” requires special computerized stimuli that minimize clues to motion from the changes in position of a stimulus (Ex. The way we interpret movement of the moon across the sky). Random dot cinematograms (RDC) present a motion signal amid spatially random background noise and can be designed to test different aspects of motion perception, but are generally available only in a research setting. It is possible to make clinical inferences on motion vision by observing smooth pursuit or optokinetic eye movements, although these movements can be abnormal in the absence of a motion perception deficit. While there is no cure for this disorder as I had mentioned before, scientists and researchers need more information to know why stroke patients are the more susceptible victims, and why not more stroke patients inherit this disorder.
References:
https://www.youtube.com/watch?v=B47Js1MtT4w I chose this video because of the content of following someone with this disorder. This was a pretty “hokey” YouTube video, but it did give a great visual on the life of someone with this disorder.
http://www.omgfacts.com/lists/9298/A-disorder-known-as-Akinetopsia-causes-people-to-not-see-motion I chose this website because it simply stated what the disorder was and also the effects of not being able to see motion.
http://vectors.usc.edu/issues/04_issue/malperception/akinetopsia.html I chose this website because it gave another scenario of someone who would have hemi-akinetopsia. It also gave some visual aids.
TERMS: Akinetopsia, cerebral akinetopsia, motion blindness, magnocellular pathway, visual cortex, lateral geniculate nucleus, thalamus, motion processing, temporal cortex, 3D, hemi-akinetopsia, spatial acuity, flicker detection, fluid motion, random dot cinematograms (RDC)
I chose to do more research on saccade. Which is a rapid eye movement between objects. It fits in our chapter because its one of the high lighted words in the chapter. The chapter is about more how we see things in motion and this is something that helps.
I have found that saccades are rapid motions of the eyes between objects. This is something that can help because the fovea has such a small area that it can actually detect, they eyes moving around so much and so quickly lets the fovea take in what is surrounding us in order to process where we are, are we safe, etc. It's also going on while you are reading a book, watching tv, and during REM sleep. You're eyes are constantly moving even when think your eyes are fixated on one object. You could just be fixated on your dog, but your eyes are still going to make these saccadic motions looking at different features on your dog telling your brain that its a dog.
Its important to remember that the saccades are just the fast jerky motion of your eye from one point of focus to another. The saccades are not what is pulling the information to your cortex. You are learning about the object between saccades when your eyes can focus on that one specific thing and actually take the time to see the features . When your eyes are moving so rapidly you don't have time to use them to see the actual features or learn anything your looking past. Only when your eye motion stops and fixates on something can you noticeably learn about whats going on in a situation.
http://en.wikipedia.org/wiki/Saccade
http://www.ncbi.nlm.nih.gov/books/NBK10991/
http://www.scholarpedia.org/article/Human_saccadic_eye_movements
Terms
Saccade, fovea, REM, motion, cortex,
I chose the time to collision/tau as my topic for this week. I found it interesting that based on nothing more than “eyeballing it” this suggests that an individual can make very specific calculations about how fast and when an object will reach a destination. I think because I am a huge baseball fan and have watched my son progress over the years I was interested in seeing if this was something that just was or could be improved upon.
It turns out the answer is yes and no. Much of the tau is innate, we see it in the wild with animals that are able to gauge the length of time it will take a predator to attack or the length of time to get to prey. We know that prey that does not have the instinct would not last in the wild, therefore it is impossible to simply get better, you either have it right or you’re dinner. We’ve all seen it before, the rabbit sitting in the yard peacefully resting. Soon someone, normally an obnoxious young boy decides to go catch it. The kid starts to slowly walk across the lawn and the rabbit just sits there, not even flinching. But at a certain distance the rabbit takes off so fast the kid has zero chance of capture. Why didn’t the rabbit run as soon as the kid started walking toward him? The reason is because he didn’t have to, with tau, the optic flow that could signal time to collision he was able to gauge how long until the boy was able to reach him.
There is evidence to suggest that as an activity is repeated tau can be improved upon. Because tau is basically a math problem done quickly in your head you can learn to calculate more precisely. This is important for many areas of life. Driving a car if someone starts to come into your lane it is important to have an idea of when to swerve. Swerve to late and you get into an accident. However you also don’t want to be constantly swerving either, then you might get pulled over and have the drunk test administered. This is something that is both innate and learned. Which is one reason why car insurance is less for people with experience.
In the world of baseball, which by the way opens in 26 days, improvement is key to success. This is especially true of batting. There is a small box that the batter stands in when up to bat. If the batter swings the bat past a certain point across home plate with no contact it is a strike. If a player steps out of the box he is out. If the batter gets hit with the ball he gets first base and a really nasty bruise. Even at the 12-13 year old range the balls are traveling 40-50 miles per hour. If a ball hits you there is no doubt you will fill a sting. If it hits on your back you can probably shake it off and be okay, it hits your leg you will probably need a runner and if it hits your hand or arm there is a really good chance you won’t be playing at least for the remainder of the game, if it hits you in the head you will probably be stunned even with a helmet. There is good reason to believe that if you love baseball you will learn to judge when that ball is coming, first your batting average depends on it and second you don’t want to get hit. There is also the issue of flinching too much. If you fall to the ground to avoid being hit you better take the bat with you or it’s a strike, and like I stated earlier if you step out of the box you’re out.
Having watched my son play for the past 10+ years I have watched timing get better. I can see where some of it is simply innate, as some players start out better than others. You can also see a difference in the kids who practice. I have watch a ball come dangerously close to Zachary’s face and he doesn’t move. He also bats well and is able to gauge the pitch and hit it at the right time based on the level and speed.
It was difficult to find a lot on this topic but what I found is that tau definitely plays a big role in perceiving contact timing but there is also more than can just be explained by tau.
Terms: tau, Time to collision, perception, optical
http://opticflow.bu.edu/research/time-to-contact-estimation
https://books.google.com/books?id=Ejc27Wrg5rMC&pg=PA95&lpg=PA95&dq=tau+in+optic+flow&source=bl&ots=IH6AupuXIT&sig=0fhuulq7wBYeHukiBcWuDlmCF64&hl=en&sa=X&ei=YdIBVfTlLtGgyATtuIKACg&ved=0CEIQ6AEwBQ#v=onepage&q=tau%20in%20optic%20flow&f=false
https://books.google.com/books?id=Ejc27Wrg5rMC&pg=PA95&lpg=PA95&dq=tau+in+optic+flow&source=bl&ots=IH6AupuXIT&sig=0fhuulq7wBYeHukiBcWuDlmCF64&hl=en&sa=X&ei=YdIBVfTlLtGgyATtuIKACg&ved=0CEIQ6AEwBQ#v=onepage&q=tau%20in%20optic%20flow&f=false
The topic I choose to write about and further my research on for week 9 blog is "akinetopsia" the book defines this as a rare neuropsychological disorder in which the affected individual has no perception of motion. This is a rare neuropsychological disorder known as askinetopsia. The book gives the example of a 47 year old man who reported seeing streams of multiple, frozen images trailing in the wake of moving objects. When the motion stopped the images collapsed into each other. He could still see stationary objects normally; if nothing was in motion he could see completely normally as we would. However, as soon as something moved it left a stream of static copies in its path. This makes tasks that are simple for us such as driving, going for walks, or bike rides extremely difficult for him and others who have askinetopsia.
Some of the fears and difficulties that those who suffer from askinetopsia every day have to deal with that I found in my research were:
-Patients suffering from Akinetopsia have reported experience frequent headaches; often bad enough to make it difficult to continue with daily tasks.
-Those affected by akinetopsia often see the world like we see it through strobe lights. They can compare how they see things all the time to how we see something with the flashing effect of a strobe light making it difficult for us to notice when something changes; it can “sneak” up on you.
-Some also may think they may be able to judge the distance of a vehicle, but before they know it the vehicle can be right on top of them after appearing very far away. This makes it difficult, if not impossible, to be a pedestrian. Making tasks such as walking extremely difficult.
-Patients suffering from Akinetopsia have reported being afraid of dogs even though they did not have the phobia before their condition. What this fear comes down to is the unpredictability and quick motion of dogs and the inability to perceive their motion; they often feel threatened by the dog not knowing what its next movement may be.
-Patients suffering from Akinetopsia have reported difficulty following conversation since the shape of the person's lips do not sync up with the sound. They often can’t understand what the person is saying because the words they are hearing don’t go with the movements they are seeing from the person they are interacting with lips; basically confusing them.
-Patients suffering from Akinetopsia are unable to enjoy movies as it appears with frames missing making the movie hard to follow and understand.
-Some patients suffering from Akinetopsia have difficulty pouring tea, water or other liquids because the liquid appears frozen and jumps from one level of the cup to the next until it is overflowing.
I chose those topic because I found it extremely interesting in our reading. It was only mentioned toward the end of the reading but the example given in the book had a lot of merit for good research. Once I started researching I was glad I choose this topic it is extremely interesting; and something that is difficult for me to imagine. I have always hated going to black light parties or strobe light parties I don't like seeing things in this view point and when I do I usually can't wait to see things "normal" again. I can not imagine having to live your entire life like these, it would make so many tasks that we take for granted so difficult.
The book stated that akinetopsia appears to be caused by disruption to cortical area MT. It is often a side affect of a prescription antidepressant drug, and if this is the case their motion perception problems could often disappear once they were off the drug or not taking it anymore. However, in other cases, akinetopsia is brought on by direct trauma to area MT that is due to a stroke or elective brain surgery. Patients in the latter category sometimes regain normal motion perception abilities several weeks after surgery, indicating that the human brain can sometimes rearrange its connections so that different areas take over the MT's motion-processing functions.
Akinetopsia is a neuropsychological disorder but it is also known as Motion Blindness. A change in the brain’s structure, often caused by lesions, interferes with the psychological process of understanding sensory information.
This happens because the visual motion processing area of the brain is anatomically separated from other functions. People with akinetopsia can still see color, spatial acuity, and flicker detection. The disorder affects the ability to reaching out to objects and catching objects. The brain actually sees things in snapshots, instead of in fluid motion. So although people with this disorder can still pretty much see everything that we can see they just see it in snapshots or pictures of what we see. I feel like this reminds me of one of the old color books that you could draw and each one changed just a little bit but when you flipped through it a motion was happening. For people with akinetopsia the book skips around on them sometimes and they get to the end movement without noticing the movements in between.
websites I used: http://www.omgfacts.com/lists/9298/A-disorder-known-as-Akinetopsia-causes-people-to-not-see-motion this was my favorite of my websites during my research because it not only explained what akinetopsia was but it also gave more examples of how it could be caused along with facts about the disorder that were helpful in understanding it more.
Now you may be wondering how you can test for akinetopsia. Testing of akinetopsia or “Motion Blindness” requires special computerized stimuli that minimize clues to motion from the changes in position of a stimulus, tests within a research setting can present a motion signal amid spatially random background noise and can be designed to test different aspects of motion perception.
Akinetopsia is related to sensation and perception because not being able to comprehend or notice movement is going to have a huge affect on how you perceive the things around you. If you are unable to tell something is moving you won't have the depth perception to move when it gets to a specific point; this disorder is extremely disruptive to those who suffer from it.
http://www.sciencedirect.com/science/article/pii/S2213323213000236 This website gave a specific case of akinestopsia which also informed me of that fact that this disorder can often be the side affect of antidepressants and yet go away when you are off of the antidepressants.
https://www.youtube.com/watch?v=B47Js1MtT4w This video showed what those with this disorder saw; it gives examples and best shows cases of how this disorder effects their personal lives.
Terms: TERMS: Akinetopsia, cerebral akinetopsia, motion blindness, magnocellular pathway, visual cortex, lateral geniculate nucleus, sensation, perception motion processing, temporal cortex, 3D, hemi-akinetopsia, spatial acuity, flicker detection, fluid motion, random dot cinematograms (RDC)
1a) Smooth Pursuit eye movement
1b) This was a main concept that was in our chapter 8 reading.
1c) I was interested in this part because it was easy to understand what is was from the book which made me what to learn more about it and if there were many cases where it could go wrong.
2)As we have learned from our chapter 8 assignment smooth pursuit eye movement is a type of voluntary movement in which the eyes move smoothly to follow an object. An example of this would be if you were to grad a nearby object and move it from one side of your visual field to the other while watching it. You would see that it appears to be moving as a “smooth” motion as opposed to a jagged, lagging one like how you might see an online video load. Another type of eye movement is called a micro saccade which is an involuntary, small, jerk like eye movement. This just means that you cannot control this type of eye movement as compare to smooth pursuit. Micro saccades usually happen when we try to keep our eyes completely still or focused in on something for a long period of time.
Smooth pursuit can be measure a couple of different ways for research purposes. The first is called a search coil. This technique is most common in primate research, and is very accurate. It is a sensor which measures the variation of the magnetic flux. An eye movement shifts the orientation of the coil to induce an electrical current. This is then translated into horizontal and vertical eye position. These coils are embedded into a tightly-fitting contact lens or a rubber ring that adheres to the eye. In animal studies, the search coil may be surgically implanted into the sclera of the eye.
Another technique for measure smooth pursuit eye movement is an eye tracker. This device is non-invasive and is often used in human psychophysics and recently also in instructional psychology. This technique is also a bit noisier. It relies on the infrared illumination of the pupil to track eye position with a camera. This is used in other field of research as well including marketing and cognitive linguistics.
Pursuit eye movement can be divided into two stages which are open-loop pursuit and closed-loop pursuit. Open-loop pursuit is the visual system's first response to a moving object we want to track or follow an object and can happen within 100 milliseconds. Closed-loop pursuit lasts until the pursuit movement is done. This stage is characterized by the connected correction of pursuit velocity to compensate for retinal slip which is the prediction of retinal movement. In simpler terms, the pursuit system tries to null retinal speed of the object of we are looking at. This is achieved at the end of the open-loop phase. In the closed-loop phase, the eye angular velocity and target angular velocity are almost equal.
Smooth pursuit requires the coordination of many brain regions that are far away from each other. This makes it particularly vulnerable to impairment from a variety of disorders and conditions. The most apparent smooth pursuit deficit is in schizophrenia patients. Schizophrenic patients tend to have trouble pursuing very fast targets in their visual field. This impairment is correlated with less activation in areas in the brain known to play a role in pursuit. These areas include the frontal eye field. However, other studies have shown that schizophrenic patients show relatively normal pursuit, compared to controls, when tracking objects that move unexpectedly. The greatest deficits are when the patients track objects of a predictable velocity which begins moving at a predictable time. This makes us believe that with schizophrenia patients there may be more of an involuntary movement with smooth pursuit since in unexpected movements are the only times it really is apparent. Autistic patients show an excess amount of visual deficits. One such deficit is to smooth pursuit. Children with autism show reduced speed of smooth pursuit compared to controls during ongoing tracking measures. However, the inactivity of the pursuit response is similar to controls or when it is apparent then it is very slow and does not happen very often for fast objects in the environment. This deficit appears to only emerge after middle adolescence after the child has reached the beginning of puberty. We believe this is because there are many hormonal changes that take place during this stage of development, and with autism the development does not happen precisely. While there are several issue that arise from autism, smooth pursuit eye movement is one that is noticeable by observation of the subject. Other two areas that show a decrease in smooth pursuit are with subjects that have gone through a great amount of trauma or suffer from post-traumatic stress disorder, and in drug and alcohol abuse. Many times when it is related to alcohol smooth pursuit returns to normal once the person is sober again. In case with drugs, if taken too often or misused, this can cause permanent damage to smooth pursuit on the neurological level within the brain. This is only in the extreme cases.
3)Terms: Smooth pursuit, eye movement, micro saccades, search coil, eye tracking, open-loop pursuit, closed-loop pursuit, autism, post-traumatic stress disorder, schizophrenia.
4) http://jn.physiology.org/content/95/2/593.long This research paper showed many deficits in schizophrenia patients along with other disabilities that show similar neural damage.
http://jn.physiology.org/content/67/1/164.long This article was on research of the eye movement of monkeys and different defects that can happen. It also went over the different techniques on how to measure eye movement.
http://jn.physiology.org/content/72/1/150.long This was another helpful article related to primates and did a better job at explain the different concepts in smooth pursuit and how it relates with different structures in the brain.
http://brain.oxfordjournals.org/content/127/12/2584.long I needed more information on different scenarios that involved damage in eye movement, and this one was great with comparing to eye movement in autistic children.
1a) State what your topic is.
My topic is Tip Link, Which is also know as Stereocilia.
1b) Discuss how the topic relates to the chapter.
Stereocilia is the process of regulating the flow of ions into and out of hair cells. Photomicrograph shows the threadlike tip links that connects the tip of each stereocilium to its taller neighbor bending the stereocilia atop a hair cell opens the ion pores, permiting a rapid influx of potassium ions into the hair cell. this relates to the chapter in many ways, this chapter talks about hearing, the process of hearing, and different types of sound waves, this is another level of the process, this process basically goes about blockage of certian things, things that could harm your hearing system, things that you choose not to hear or register into your brain, it connects different fibers, nerves together so the information you're receiving are well accurate and go exactly where their supposed to go.
1c) Discuss why you are interested in it.
I'm interested in this because, at first, i couldn't pronounce the world "stereocilia", i had to look it up, then i thought since the first part of it had "stereo" in it, it'd have something to do with music, comes to find out, it doesn't. eventually, i figured out that it was much more important than i thought. stereocilia is very important to us, because without that part of the connection into the brain, then we would misinterpret many things, it kind of regulates information accordingly so we can understand them better and they get to our brain in an orderly fashion.
2) As i look up some research about stereocilia, there's really not much on it, i found a video that goes through the purpose and the process of it, another study goes over what could happen if the stereocilia was to be block off, many problems could appear if this were to ever happen, it usually causes hear lose, it cause people to misunderstand information and make them ask people to repeat themselves frequently,. one of the main things that elderly people lose when it comes to hearing is their sterocilia processing, because they are older, not alot of protection is in that area, so this simply gives them disadvantages in hearing and really make the process of them going deaf a lot of quicker. ways that we can avoid this happening to us would be that we don't listen to loud things or loud music alot, that we get check ups on regular bases and that we do the best we can to not get bacterial infections because that increases our chances of losing that part of our hearing, which is the very important part.
4)URLs
This is a representation of what stereocilia does for you
https://www.youtube.com/watch?v=lDXVZOU_f_E
Some explanation about stereocilia.
http://en.wikipedia.org/wiki/Stereocilia
This is more on the medical side of things about stereocilia
http://www.ncbi.nlm.nih.gov/books/NBK10867/
I decided to look further into time to collation TTC. because its amazing how we are able to do the calculations of an when one thing will hit another even if we fail at math. its an ordeal that our brain does without us even having to think about it. We do this all the time from baseball,basketball, other sports to driving in the city. when driving we are always stooping before we hit another car or when stooping from 40 miles per hour to 0 for a stop sign a person or a deer.
http://www.sbes.vt.edu/gabler/publications/Kusano-Gabler-SAE-TTC_EDRs-2011-01-0576.pdf
http://serinet.meei.harvard.edu/faculty/peli/papers/pundlik736.pdf
Estimating time to collision (TTC) can be assisted by computer-vision based risk assessment with an uncalibrated camera. The time to contact is of interest to many fields, including experimental psychology to robotics. It can be defined as the time for an object in the real world to reach a camera plane, assuming the relative speed is fixed. It is the ratio of distance and speed of the same kind of processing that takes place in the human visual system. Because of the difficulty of determining a variety of motion trajectories, some researchers are working on the use of feature points – an aggregation of local scale change and motion information. Tracking and detection of feature points are performed on the input image sequence such as happens in the human eye.
Terms: vision based risk assessment, time to contact, experimental psychology, robotics, motion trajectories, feature points, input image sequence
Chapter 8
1a) State what your topic is.
Akinetopsia- a rare neuropsychological disorder in which the affected individual has no perception of motion.
1b) Discuss how the topic relates to the chapter.
Directly related, this is the last term from chapter 8, Akinetopsia (pg. 240).
1c) Discuss why you are interested in it.
There was a story about a man who couldn’t see motion, which is what was so intriguing to me and it also talked about a woman who saw her arm moving like a cartoon-like motion. I wanted to know more about this and I also wanted to find out the man’s name. I researched it but to no avail.
2) Next, we would like you to take the information you read or viewed related to your topic, integrate/synthesize it, and then write about the topic in a knowledgeable manner.
Akinetopsia, also known as motion blindness, is a neuropsychological disorder in which a person cannot perceive motion in their visual field. In other words, a patient with this disorder has the inability to see moving objects. The subject although can see stationary objects without issue. In these individuals there is a change in brain structure, usually due to an injury and or maybe they were born that way, it disturbs the psychological process of understanding sensory information. People and/or patients with akinetopsia struggle with many issues in their day to day life such as reaching for objects and catching objects.
http://brain.oxfordjournals.org/content/114/2/811.long - this site explained akinetopsia and talked about new research.
http://www.psychologyconcepts.com/akinetopsia-akinetopsia-or-motion-blindness/ &
http://www.allpsych.uni-giessen.de/karl/teach/SemVisNeuro/Zeki1991.pdf one leaded me to the other; intertwined (a review about my topic which I found very informative). It’s a must read.
http://mooreperceptionproject.weebly.com/patient-lm.html - this is a website about the patient LM, a 43-year old female, admited into a hospital in Munich in 1978 complaining of extreme headaches and feelings of vertigo. She was diagnosed with thrombosis of the superior sagittal sinus (also known as as the superior longitudinal sinus, within the human head, is an unpaired area along the attached margin of falx cerebri. It allows blood to drain from the lateral aspects of anterior cerebral hemispheres to the confluence of sinuses) which resulted in bilateral lesions of a part of the visual cortex.
Terms: Akinetopsia, perception, psychological processes, disorder, sensory, patients, motion, neuropsychological disorder, perception of motion, thrombosis, vertigo, headaches, bilateral lesions, visual cortex, sagittal sinus, blood, lateral,
For my topical blog I decided to do some more looking into Balint’s Syndrome. It relates to chapter eight because it exemplifies the importance of motion perception and the consequence of damage to the part of the brain that is involved in perceiving motion. I don't remember if I came across this, in a search long time ago, or if something was mentioned in the text book. But it seemed interesting in a weird way and here we are.
This disorder is very uncommon and not completely understood. Essentially, this is a severe impairment of a triad of neuro-psychological regions; the inability to perceive the visual field as a whole, difficulty fixating the eyes on a certain area, and the inability to move the hand to a specific object by using vision. This syndrome was named in 1909 by the Austro-Hungarian neurologist Rezso Balint, who was the first person to identify it.
Balint’s syndrome occurs most often with an acute onset as a consequence of two or more strokes at more or less the same place in each hemisphere. The most frequent cause is said to be some sudden and severe hypo-tension, resulting in bilateral infraction of the occipito-parietal region. More progressive symptoms of this disease have been found in degenerative disorders such as Alzheimer’s or other traumatic brain injuries that border the parietal and occipital lobes of the brain. It is cautioned that a lack of awareness of this syndrome may lead to a misdiagnosis and resulting in inadequate or unneeded treatment.
Simultanagnosia is the inability to perceive simultaneous events or objects in one’s visual field. This spatial disorder of visual attention has been referred to as a constriction of the individual’s global gestalt window or their visual window of attention. People with this defective attribute have a hard time retaining attention to a large scene and have a restricted window of fixation. Some studies show that patients with simultanagnosia have an extreme issue with competition between objects, this therefore, makes it difficult to disengage from one object and move onto another.
Ocular apraxia is a another debilitating issue that is associated with Balint’s syndrome. This is the inability to carry out familiar movements when asked to do so. People affected with this are ready and willing to carry out such commands but are unable to physically perform the task. Balint referred to this as the “psychic paralysis of gaze”, the inability to voluntarily guide movements, changing to a new location of visual fixation. The most frequent and disabling deficit of this syndrome is the neglect that manifests itself as a spatial representation and attention on the same side as the lesion. There is no single test or factor that can be used to diagnose apraxia. Optic ataxia is the inability to guide the hand toward an object using visual information. This is characterized by an impaired bisual control of the direction of arm-reaching to a visual target, accompanied by defective orientation and grip formation. Essentially it takes patients longer to reach for an object and their ability to grasp an object is also impaired.
The cause of Balint’s Syndrome is due to the damage to the top part of the temporal occipital lobes on both sides of the brain. Furthermore, the top part of the parietal lobes on both sides of the brain may also be affected. Since there is the possibility of a lack of awareness of the syndrome, it is important for doctors alike to be aware of the symptoms. The first initial noticing of the issue would be seen by the therapists providing rehabilitation following brain lesions. Any severe disturbance of space representation, spontaneously appearing following bilateral parietal damage, is the only strong suggestion that Balint’s Syndrome could be a possibility.
TERMS: Bilant’s Syndrome, simultanagnosia
Sources:
http://neurology.about.com/od/Stroke/a/What-Is-Balint-Syndrome.htm
This link gives a good description of what it is, and how some deal with it, simple reading.
https://www.youtube.com/watch?v=4odhSq46vtU
I really like this video, just by watching it you get a really good idea of what people with the disease deal with
http://en.wikipedia.org/wiki/Simultanagnosia
Wiki seemed to have the best overall info on simultanagnosia so I went with it