What I would like you to do is to find a topic from the chapter you read so far in class 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.
Once you are done with your post make list of the terms and terminology you used in your post.
Let me know if you have any questions.
I enjoyed reading about touch physiology and the sense organ and receptors for touch in chapter 12, because I really like learning about the anatomy and physiology of our sense organs. I have enjoyed learning about sight and sound in previous chapters and am looking forward to learning more about the sense organs regarding touch.
Unlike the sense organs for sight, sound, smell and taste, the sense organ for touch is in the largest and heaviest sense organ on our body-our skin. The skin covers an area of 1.8 meters squared and weighs 4 kilograms. Touch receptors are embedded in the skin all over our body, as well as in our mouths and within our muscles, tendons, and joints. These touch receptors are located in both the outer layer (epidermis) and underlying layer (dermis). The dermis consists of nutritive and connective tissues, within which lie the mechanoreceptors. There are multiple types of touch receptors that form the basis for “channels,” which are specialized information-processing subsystems that each contribute to the overall sense of touch. The textbook offered a helpful example of this concept: if you wrap your fingers around an ice cube, different channels convey information about its coldness, shape and smoothness. Each touch receptor is characterized by three attributes: type of stimulation the receptor responds to (pressure, vibration, temperature changes), size of receptive field (extent of body area to which the receptor will respond), and rate of adaptation. There are two types of adaptation rates, fast-adapting and slow-adapting. Fast-adapting (FA) receptor responds with bursts of action potentials when its preferred stimulus is first applied and when it’s removed, but it doesn’t respond during the steady state between stimulus onset and offset. Slow-adapting (SA) receptor remains active throughout the period during which the stimulus is in contact with its receptive field.
There are four receptor types known as ‘tactile receptors’ called mechanoreceptors because they respond to mechanical stimulation or pressure (pressure or vibration). Mechanoreceptors enable us to detect touch, monitor the position of our muscles, bones, and joints (proprioception ), and detect sounds and the motion of the body (actually performed by the inner ear). Proprioception is our ‘body sense,’ which enables us to unconsciously monitor the position of our body. It depends on receptors in the muscles, tendons, and joints.
The endings of the four receptor types are named after the scientists that described them, the Meissner corpuscles which is a specialized nerve ending associated with fast-adapting fibers with small receptive fields (FA I). The Merkel cell neurite complexes which is a specialized nerve ending associated with slow-adapting fibers with small receptive fields (SA I). The Pacinian corpuscle, a specialized nerve ending associated with fast-adapting fibers with large receptive fields (FA II). And the Ruffini ending, a specialized nerve ending associated with slow-adapting fibers with large receptive fields (SA II). The Meissner and Merkel receptors are located at the junction of the epidermis and dermis that tend to have smaller receptive fields than those of the Pacinian corpuscles and Ruffini endings, which are embedded more deeply in the dermis. The Pacinian corpuscle has a single afferent nerve fiber and its end is covered by a sensitive receptor membrane whose sodium channels open when the membrane is deformed in any way. It is surrounded by several concentric capsules of connective tissue, with a viscous gel between them. The final link listed will direct you to images of the Ruffini ending.
I enjoyed reading about touch physiology and the tactile receptors because I have always enjoyed learning about anatomy and physiology. I think the touch sensory organ is very interesting and look forward to learning more about it.
Sources:
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Mechanoreceptors.html
http://www.neuro.uu.se/fysiologi/gu/nbb/lectures/Pacini.html
http://www.ncbi.nlm.nih.gov/books/NBK10895/
http://medical-dictionary.thefreedictionary.com/Meissner+corpuscle
http://www.britannica.com/EBchecked/topic/512338/Ruffini-ending
http://www.google.com/images?q=ruffini+endings&sourceid=navclient&rlz=1T4ADFA_enUS426US428&gs_upl=0l0l1l944320lllllllllll0&gs_l=serp.1.4.0l5j0i15j0i18l3.15032l21729l0l26834l22l22l2l4l5l0l270l1890l1j11j2l14l0.frgbld.&oq=ruffini&aq=0&aqi=g10&aql=&oi=image_result_group&sa=X
Terms: sense organs, touch, skin, touch receptors, epidermis, dermis, connective tissues, mechanoreceptors, channels, stimulation, receptor, pressure, vibration, receptive field, rate of adaptation, fast-adapting, slow-adapting, tactile receptors, proprioception, Meissner corpuscles, Merkel cell neurite complex, Pacinian corpuscle, Ruffini ending
For my topical blog I decided to talk about virtual haptic environments. These virtual reality environments are mostly used as training tools for novice surgeons. There is a ton of research being done on this subject to decide how effective this is as the use of a teaching tool. This tool is mostly used in the training of surgeons, by using their motor skills to get the fake operation completed. This is most notable used for minimally invasive surgery techniques rather than full blown surgery. In the research article about this by Jenny Christensson, she says that “the future of surgery is now but the future of any new technology depends upon how well the training is, i.e., no matter how good the technology is, the overall outcome of surgical performance requires training and exercise.” Locations in this exercise simulate locations inside the box that the surgery is being “performed”. These locations simulate rigid surfaces with material properties such as coefficients of friction. When grasping the handle, and move your hand, this causes motion of the probe in the assigned to a wall. You then encounter resisting forces on the handle which depend on the speed and direction that the handle is moved. Most notably, virtual haptic environments are used in video games, but they can be used in many other practices.
Other research is working on ways to help out with comfort of the machine and to the person that is using it. Muscular fatigue is endured when using the machine for long periods of time. The main reason this happens is because of the uncomfortable posture of the arms, which must be kept outstretched horizontally while supporting the weight of the exoskeleton.
Furthermore, haptic research does what computer graphics research does for human vision research. The importance of haptic technology extends beyond scientific research, this technology opens the door to new applications in a variety of fields. To understand haptic environments fully, one has to control the haptic stimuli occurring during interaction with an environment. Typically this involves systematically controlling and/or varying the haptic signals (mechanical signals) that define the stimuli.
TERMS: virtual haptic environments
http://www.cse.chalmers.se/research/group/idc/theses/05/pdf/jenny.pdf
www.enactivenetwork.org/download.php?id=121
http://www.isfh.org/GR-Principles_Haptic_Percept_VE.pdf
I have always been amazed by our ability to easily pick out a familiar face in a crowd of people. But what happens when we lose this ability? I have chosen to write this weeks topical blog about a condition called prosopagnosia, which is the inability to recognize faces. The interesting thing about this disorder is that all other visual sensations remain properly functioning; most people have “normal” visual capacities and memory functions. An important aspect to recognize in individuals with prosopagnosia is that they are unable to experience the familiar feeling of seeing a face. I imagine a life with this disability would be quite different in comparison to my life. I couldn’t imagine not having the familiar, warm feeling I experience when I see my family or my friends.
There are two main problems occurring with prosopagnosia. Either the new information (new face) is not being encoded into memory, or there is a problem with matching the new information to the previously stored information in the memory. Because prosopagnosia is specific to the deficiency to recognizing faces, it shows that there must be a specific area in the brain dedicated to this function. There is a debate as to where in the brain these processes occur, but the most accepted area is called the fusiform gyrus, nicknamed the fusiform face area (FFA). This area is targeted because when brain activity is recorded, the FFA is highly active when faces are being viewed by the individual in most cases. I say most cases because there is a debate about if this area is specific to faces.
Those who oppose the FFA as being specific to faces argue that this area is specific to objects that the individual is an expert at. The argument states that humans are experts at faces, in such that they are able to recognize specific features are how they compare to one another. They state that those with prosopagnosia lose the ability to recognize other objects that they are an expertise in. For example, if a person spends 20 years of their life working with dogs, then this area would also be specific to recognizing dog characteristics. This study was conducted, and it found that when these individuals were shown images of dogs, their FFA was highly active, similar to when they were shown pictures of faces. This suggests that prosopagnosia may be more than the loss in recognizing faces.
Those with prosopagnosia are not doomed as far as recognizing people. These individuals learn to rely on specific cues, such as listening to a person’s voice or remembering their clothes. Many people with this condition can recognize people as soon as they hear the person’s voice, which shows how interesting this condition is. When a woman is shown faces of women and she is told to pick out her mother, she is unable to do so. But when the same woman is shown pictures of women including their clothing, she is able to pick it out almost immediately. Individuals with this condition learn to adapt to their situation, because they are not likely to change it.
Another interesting thing I found about face recognition is how different it is from object recognition. With face recognition, our brains pay attention to every detail of a face. It looks at the structures on the faces, as well as their spatial locality on the face; or where on the face they are located in reference to the other features. In sum, face recognition is very focused on details. Object recognition is quite the opposite. When our brain is trying to recognize an object, it often generalizes the object. This is beneficial to our ability to recognize objects because if we were to pay attention to every specific detail, then our brains would be overloaded. This is different because objects can come in many different shapes, sizes, colors, etc. One object can come in 10 different sizes and still be the same, so it is important to generalize an object in order to recognize it quickly. Whereas if we were to generalize faces, then we would not be able to recognize anything, which would mean we would have the condition called prosopagnosia.
Terms: Face recognition, encoding, prosopagnosia, object recognition, fusiform face area, cues.
Sources:
http://en.wikipedia.org/wiki/Prosopagnosia
http://www.youtube.com/watch?v=vwCrxomPbtY
https://www.faceblind.org/research/
I decided to research more on retinitis pigmentosa (RP). This comes from chapter two. RP is disease that is common in families, which makes it hereditary. It is the dieing out of one's photoreceptors and degeneration of the pigment epithelium. Most people first find it hard to see out of the peripherals and under low light conditions. In the book they described a man who could not see starts. He would look into the nights sky and when he noticed a difference in his vision, he couldn't see the stars that he picked out in his peripheral vision.
RP comes on usually at an early age. Over 2 million people are affected with this disease and not a lot of people know about it. There are a lot of video's online of people who are not yet blind, but are soon to become blind. I can not even imagine this fate. Especially if you knew it was coming, and came on at a slow to rapid pace. It depends on your gene's how fast it comes on, but it is usually a process over several years. A video I found on youtube shows just how RP effects one's site over a period of time.
RP effects lives the rodes and cones. Making it difficult to impossible to drive or play certain sports. RP is usually diagnosed in earlier years. Parents can suspect that their child might possibly have RP if their child is very clumsy or has trouble learning how to read. Of course children are very clumsy to begin with, but if your child is having trouble in sports, and seeing the ball, this might be an early sign of RP.
Unfortunately there is no cure for RP. This is what makes it so sad. Once you are diagnosed, you simply play the waiting game and don't take for granted the lovely things you see everyday until later in life when you will become blind.
Terms: Retitinis pigmentosa, rodes, cones, photoreceptors.
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002024/
http://www.youtube.com/watch?v=dGElhMnDF6c&feature=related
http://www.youtube.com/watch?v=5a4xDttzDjo&feature=related
http://www.youtube.com/watch?v=MU1JZmUac98&feature=related
Last weekend, I traveled to D.C. The trip was fine, but the worst part of it was the travel; I rode on a plane to get there. I’m not afraid of flying by any means, but I do get airsickness, which is very unpleasant to me. I’m also somewhat susceptible to motion sickness because whenever I’m a passenger in a car for some amount of time, I get nauseous. What’s interesting about this experience is that it’s completely nullified by being in control of the vehicle, by driving. My recent experience sparked an interest in this subject, and my blog will be about motion sickness.
Motion sickness is due to a discrepancy in the incoming neural signals of the visual system and the vestibular system. Either the vestibular system is detecting some sort of change in the environment that the visual system does not (in travel), or vice versa (in video games, virtual reality, or looking through microscopes). This discrepancy usually gives reason for the brain to send a signal straight to the sympathetic part of the vagus nerve, which stimulates an upset stomach, nausea, and even vomiting. Obviously, vomiting is the most severe of these outcomes, and this is due to a more intense stimulation of the vagus nerve (by a larger discrepancy between the visual and vestibular systems). The area that is most correlated as the “central processor” of self-spatial perception and movements related to this perception are the cerebellum. This is reinforced by studies that show lesions of parts of the cerebellum decrease motion sickness. However, most healthy individuals will experience motion sickness sometime in their life; and, like most things, this can be blamed on evolution. The most credible theory of motion sickness is called the toxin theory. This theory is based off of your brain predicting an ingested toxin to be the cause of this discrepancy between two of your perceptual systems. The visual system and the vestibular system have been working in harmony for millions of years. When differences between the two perceptual systems arise in more primitive times, it is due some poison that you ate. As you may have experienced with alcohol, it is a common symptom for toxins to affect your vestibular system. This relationship has stayed constant throughout many many generations, and so it has become genetically hardwired into your brain. The onset of modern society has been in the lifetime of two or three generations, so I would assume genetic rewiring is not going to be a natural function.
What does this say about perception? First, this shows how complex the perceptual systems are. More drastically though, it shows how interrelated the perceptual systems are. Throughout the semester of learning individual perceptual systems, I fear some have lost focus on the fact that all of these systems are independent, yet synchronous. Your sensations may be independent in their specific biological systems of measurement, but perception is a conglomeration of all of the senses; also possibly being a sum greater than its distinct parts.
Terms: motion sickness, visual and vestibular systems, sympathetic tract of the vagus nerve, cerebellum, toxin theory, gestalt perspective of perception.
http://scienceblogs.com/oscillator/2010/07/motion_sickness.php
https://en.wikipedia.org/wiki/Motion_sickness
http://www.uni.edu/walsh/neuro99.html
I decided to write about music therapy and how there are cultural differences within music therapy. Music therapy uses music to improve physical, emotional, mental, social, and spirtual facets of its pacients lives. It is a form of an expressive therapy by which a professional music therapist helps their patients by signing, song writing, dancing, listening, and discussing music. It is often used in medical hospitals, cancer centers, schools, recovery programs, psychiatric hospitals, and correctional facilities. These practitioners use music thereapy to promote wellness, manage stress, alleciate pain, express feelings, enhance memory, improve communication and promote physical rehabilitation. Music therapy has been around since 400 B.C. One type of music therapy that I found particularly interesting is called neurological music therapy or NMT. This form of music therapy is modeled on neuroscience and is mainly inteded to help people who have a neurological disease affecting cognition, movement, or communication. It can be used to help people who have suffered a stroke, had a traumatic brain injury, have Parkinson's, have Alzheimer's, or who have autism. There are a lot of techniques used to help patients. Patterned sensory enhancements uses ryhthum, melody, and harmony of music to spacial and force cues of movement. Therapeutic singing pratices articulartio to increase breath control and posture. Oral motor and respiratory exercises help muscle control that facilitate production of speach.
Although these techniques have been proven to work, music is not a universal language. The theorpy needs to be slightly changed depending on how is listening to the music. In Sudanese children it was found that clear pulse and syncopated rhythums worked the best. Some cultures do not have the same range as we do. Also the use use of different musical instrauments must be used to get the greatest response of its patients. Caucasians generally use orchestra music, African Americans choose jazz, and Tauwanese choose harp. All these factors are important to study and understand so when music therapy is used on different cultures, it is used as effectively as it can be.
Terms: Rhythm, melody, harmony, range, tempo
http://espace.library.uq.edu.au/eserv/UQ:10271/cj_healing.pdfhttp://www2.dsu.nodak.edu/users/bharris/Research/identifying.pdf
http://en.wikipedia.org/wiki/Neurologic_music_therapy
http://www.neurosong.com/index.php?option=com_content&task=view&id=35&Itemid=43
http://en.wikipedia.org/wiki/Music_therapy
Back in Chapter 11, as a music lover I was interested in the topic, and as a psychology major aware of Music Therapy, but I really don’t know what it is and what it does. I know it’s an accepted means of therapy so it’s clearly affective and merely a placebo. So I chose to do my topical blog on music therapy.
Music itself is made up of chords played at different tones, frequency, pitch and timbre. Listening to music affects a person’s mood. And as music therapy is an allied profession and en expressive therapy, the therapist uses that to influence the individual. In music therapy people sing, listen, play and move to music to improve mental and physical health. Using for a veracity of reasons with a variety of populations. Some of the websites I looked at actually had a commonality of being done at assited living facilities and hospitals. Having worked at an assisted living facility over the summer I could understand why such a thing occurs. Though the place I worked at never engaged in music therapy, music was played however. It also is apparently a good way to relieve stress, and as a college student lowering my leave of stress is good. Music therapy is much like art therapy, helpful in a variety of ways in a variety of settings. It’s a very helpful and malleable kind of therapy. Promoting wellness, management of stress, alleviating pain, expression of feelings, memory enhancement, improving communications and physical rehabilitation. Amazing what a few melodies, rhythms can do for a person. Music is all about manipulating sound to form it into a sequence of sounds to make music itself. Course the key thing about music therapy is that because there are so many different kinds for music, but for the therapy to be affective it has to be the kind of music a person enjoys. Same with when relieving stress, the person has to enjoy it for it to be affective.
http://www.holisticonline.com/stress/stress_music-therapy.htm
http://www.musictherapy.org/
http://en.wikipedia.org/wiki/Music_therapy
After reading some of chapter 12 and going to class Tuesday I became interested in the phantom limb. I really just wanted to find out some more information about what goes on when someone has a phantom limb. I find it fascinating that our minds still believe there is a limb there when there really isn’t.
When someone has a phantom limb they have the sensation that that limb is still attached to their body. When initially learning about the phantom limb it really doesn’t seem like a problem. There really doesn’t seem to be a reason to worry when someone has a phantom limb, it shouldn’t really affect their life, but it usually does because in most cases when someone has a phantom limb they also have phantom limb pain.
It is also very fascinating to me that when someone has a phantom limb they still perceive the limb as being touched. This was discovered mainly by Ramachandran and colleagues. It was discovered because of the cortical homunculus, this is a map of where the parts of our body are in our brain. Our face is next to our arm, so when parts of the persons face are being touched they perceive this as their phantom arm being touched. Our brain in a way is over correcting itself. It is filling in the blanks.
When someone experiences phantom limb pain there is a sensation that the limb is still there and that there is pain in that limb. The phantom limb and phantom limb pain comes from our brains and our spinal cord. This was shown in the video during class. They are able to feel like the limb is there because the brain still thinks it is. Doctors and researchers really didn’t know how to fix this pain. In many cases the phantom limb pain can continue on for years, so it is very important that something is being done about it. Until recent years doctors and researchers believed it was a problem with neurons and scar tissue being built up where the amputation took place. To correct this they usually did another amputation which almost always made the pain worse in the phantom limb.
Ramachandran found that mirror therapy seemed to work the best in situations where there is phantom limb pain. This is done by placing a mirror in between the phantom limb and the limb that is still there. When the person moves their working limb they perceive the movement as coming from their phantom pain. Although this doesn’t stop the pain completely, it does help. Also it is a very cheap way to eliminate the pain that is going on in the phantom limb.
I also watched another video on the phantom limb. It was about a man who had lost his leg. He had said that the pain was often times very bad or just uncomfortable. He felt as if his phantom leg was in an awkward position and he could not fix it. His therapist suggested he try the mirror therapy. This seemed to work perfectly for him. He was always very happy when he finished with the therapy. He said it felt just like he was moving his phantom leg. He also said it really helped with the pain.
Terms: phantom limb, phantom limb pain, spinal cord, neurons, cortical homunculus
http://en.wikipedia.org/wiki/Phantom_limb
http://www.webmd.com/pain-management/guide/phantom-limb-pain
http://www.mayoclinic.com/health/phantom-pain/DS00444
http://www.youtube.com/watch?v=YL_6OMPywnQ
This week I was interested in learning about thermoreceptors, warmth fibers, and cold fibers. I was interested in this for a couple of reasons. The first is that with it being a little bit colder these last couple of nights I have been waking up cold because my significant other has been stealing the blankets and the second reason is that while at work on Wednesday I was reading a book with a 1st grader about cotton mouth snakes. In the book it had a little fun fact that said that these snakes could recognize a temperature difference at .04 degrees. While trying to explain what this meant to the first grader the theory of the just noticeable difference came to my mind. We discussed how much the room temperature would have to change in a matter of minutes for the student to notice, we decided on at least 10 degrees to really feel the difference that quickly. Then we compared it to the snake and the child realized how crazy this was.
The normal human body can regulate temperature between 68 and 130 degrees F. At this temperature out bodies generally maintain a temperature of 98.6 degrees unless it is trying to fight off an illness. This is all regulated by the central nervous system. The hypothalamus is where the most temperature sensors are located. When I think about our body trying to regulate temperature at night while we are sleeping I relate this to our body trying to regulate sound. In class I believe that we came to the conclusion that we still hear sound at night and I know that our body still regulates temperature at night because this is just common sense. It would make sense that our body would be created to control those two senses even while sleeping because both of these could pose a threat. Extreme cold or heat could obviously kill you and a loud noise at night could mean a fire.
While sleeping; people can have terrible issues with being too hot or over producing body heat.
When the body produces heat this is called thermogenisis. Many companies have tried to make a profit based on this normal body function. One company creates hot and cold fiber pillows. These are advertised as providing therapeutic relief for many things such as tension headaches, upper/lower back pain, and increase blood flow. I am not sure if these really work but thought it was interesting.
The final website I visited is a little off topic but none the less important. After watching Dr. Ramashandran on Youtube I became interested on those topics in psychology that used to but to some extent still are somewhat of a taboo for researchers. One of these was creativity. The article that I read discussed how creativity is the only solution for our worst problem, creativity. Yes, this sounds confusing at first but I began to really understand what the person was talking about because of some good examples. Basically, if we as humans begin running out of a resource (gas anyone!) we try to think of another resource to replace it only to find that we will soon exhaust another resource and so on. How do we stop this cycle? I think this is a good question for psychologists especially because of temperature regulation. In many parts of the world we rely on electricity and natural gases to heat and cool our home and someday that could run out. How do we create a less wasteful population and find ways to change habits and mind sets to be more resourceful? This is an important question that all educated people should be educating their self on.
3 websites:
http://www.npr.org/blogs/krulwich/2012/04/12/150492481/jonah-and-his-many-many-whales
http://www.healthline.com/galecontent/thermoregulation
http://www.yourmedicalsupplystore.com/Details.cfm?ProdID=103&category=0
Terms: thermoreceptors, warmth fibers, cold fibers, just noticable difference, central nervous system, thermogenisis, Dr. Ramashandran, and hypothalamus.
After learning about the mirror imaging treatment for phantom limbs, I decided to do a little more research on this. This subject impacts me greatly because of my grandfather having two phantom limbs. He had both of legs amputated due to his diabetes. A phantom limb is the sensation one has after they have either of their limbs amputated. In roughly 60 to 80% of amputees report significant pain of their phantom limb. The pain can be anything from a muscle cramp to the abnormal positive the limb may be in. It possible that this occurs in other areas of the body besides arms and legs, it has been reported that this sensation can be found in either an extracted tooth, amputated eye or breast. Phantom pains also occur in individuals who are born with a missing limb. Phantom pains occur when nerves that would normally innervate the missing limb cause pain. Patients describe this phantom pain as a burning or similarly strange sensation and can be extremely agonizing for some people. Individuals also have symptoms such as cold, squeezing, tingling, cold or tightness of the limb.
Their are specific nerves that are located either on the stumps of the limb or their face that be associated with the phantom limb. Many patients report that if for example, they have an itch on their missing index finger they can relieve the itch by sratching a specific part of their face or stump. My grandfather complained all of the time that his big toe itched and the only way he could relieve that sensation was to scratch his cheek. The theory at first for phantom limbs were the severed nerve endings after a limb was removed. However new theories now argue this statement, a new and proven theory now shows that the primary somatosensory cortex undergoes substantial reorganization after the loss of sensory input.
Terms: phantom limbs, mirror imaging treatment, amputate, primary somatosensory cortex, loss of sensory input.
3 Websites:
http://www.youtube.com/watch?v=YL_6OMPywnQ
http://en.wikipedia.org/wiki/Phantom_limb
http://www.webmd.com/pain-management/guide/phantom-limb-pain
In researching potential topics for this blogpost, I came across a fascinating third type of photoreceptor in the eye called intrinsically photosensitive retinal ganglion cells (ipRGCs). The scientific history of these seemingly minor neurons (they only comprise about 1 to 3 percent of all retinal ganglion cells) is actually quite bizarre. Back in the '20s, a Harvard grad student named Clyde Keeler bred his own mice in order to compare their eyes to those of other species of animals. As fate would have it, half the mice fell victim to a genetic mutation that prevented them from growing any rods and cones! Though the mice were blind, for some reason the grad student decided to shine a light upon one's eye and was startled to find that the pupil still contracted! However, as is often the case with scientific breakthroughs, this discovery was largely ignored for 70-odd years.
Then in the early '90s, a pair of Oxford neuroscientists rediscovered these specialized cells and found that they played a role in regulating the circadian rhythms that dictate a mouse's sleep cycle among other daily bodily functions. Since this ipRGC renaissance, a great deal of research has been done on their role and function within the visual system. Researchers have found that these neurons express a photopigment called melanopsin that absorbs light at a different maximal wavelength than do corresponding pigments of the rods and cones. Melanopsin also plays a role in initiating the pupillary light reflex, which explains why Keeler had observed the phenomenon in rod and coneless mice seven decades prior. More recently, in 2007 the Keeler study was basically replicated in rod and coneless humans to see if the same sort of non-visual cellular architecture existed in the eyes of both mice and humans.
As it turns out, humans also have the same sort of ipRGCs that help to dictate functions of their own pupillary dilations and circadian rhythms! In fact, this once again indicated that these nonclassical photoreceptors perform these sorts of functions independently of rod and cones! This is because, instead of extending to visual regions of the brain like their "sighted" counterparts, these photoreceptors branch directly to areas of the brain such as the suprachiasmatic nucleus and the thalamus, directly affecting circadian, neuroendocrine, and neurobehavioral bodily responses to the presence of light. Subsequent research has also been conducted on the effects of ipRGCs on sufferers of migraine headaches. These studies show that melanopsin may indeed play a direct role in thalamic pain sensation due to light sensitivity.
Reading about these underpublicized visual cells was quite novel for me - it is kind of a pity that we hear so much about rods and cones while ipRGCs go by the wayside. This research fits in with most of the sections of our book on visual perception, perhaps most especially with Chapter 2 and the analysis of the retina and its ganglion cells. The part that I found most intriguing about all this is how all along the eye has had a largely unrecognized secondary function. We think the visual system is all about sight in much the same way that we typecast our ears as only being used to hear. Nevertheless, this is clearly not the case - just as our ears have a major secondary task in moderating our sense of balance, so too do the eyes have an additional purpose in regulating non-visual functions such as our circadian rhythms.
http://en.wikipedia.org/wiki/Photosensitive_ganglion_cell
http://discovermagazine.com/2012/jan-feb/12-the-brain-our-strange-light-detector
http://www.sciencemag.org/content/295/5557/1065.short
http://download.cell.com/current-biology/pdf/PIIS0960982207022737.pdf?intermediate=true
http://www.nature.com/neuro/journal/v13/n2/full/nn.2475.html
http://news.sciencemag.org/sciencenow/2010/01/11-01.html?etoc
Terms: intrinsically photosensitive retinal ganglion cell (ipRGC), rod, cone, circadian rhythm, melanopsin, pupillary light reflex, suprachiasmic nucleus, thalamus
The topic I wanted to research a little bit more that we had learned about in chapter 2 is astigmatism. Astigmatism, according to Wiki, is an optical defect in which vision is blurred due to the inability of the optics of the eye to focus a point object into a sharp focused image on the retina. This could be due to a irregular or toric curvature of the cornea or lens. The reason I was interested in learning more about it was when I was shuffling through the book just looking at some things, I stumbled across the term and was curious about it. Naturally when something strikes my interest I have to learn more about it.
There are two types of astigmatism, regular and irregular. Irregular astigmatism is usually caused by a corneal scar or scattering in the crystalline lens, and cannot be corrected by standard lenses, but can be corrected by contact lenses. A toric lens can correct regular astigmatism arising from either the cornea or crystalline lens. Common symptoms of astigmatism are blurry vision, squinting, asthenopia, fatigue, and headaches. The test commonly used to diagnose astigmatism is by a standard eye exam, along with a refraction test. There are a few ways to correct this condition and the most common ways are with glasses, contacts, or refractive surgery. There really wasn’t too much to this topic, but it was still interesting to read about.
Terms- Astigmatism, optics, retina, cornea, lens, crystalline lens, standard eye exam, refraction test.
http://en.wikipedia.org/wiki/Astigmatism_(eye)
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002010/
http://www.aoa.org/Astigmatism.xml
I chose to do further research on thermoreceptors for this week’s topical blog. Thermoreceptors are located in chapter 12 the Touch chapter of our book. The main reason that I chose to do my research on thermoreceptors is because I am amazed that the body was designed in a way that can tell itself what is going on with the body so accurately. Not only can the body figure out that there is a large change occurring but it also has the capacity to set a plan in motion to counteract the issue. Thermoreceptors are cutaneous receptors, which mean that they are sensory receptors that are found in the dermis or epidermis. Along with thermoreceptors cutaneous mechanoreceptors and nociceptors are also cutaneos receptors.
I want to first discussed the responsibility and make of thermoreceptors. As I mentioned already thermoreceptors are located in both the dermis and the epidermis. There are two types of thermoreceptors. There are the warmth fibers and the cold fibers. Being true to their names the warm fibers tell when skin temperature is rising and the cold fibers do the opposite. The cold fibers outnumber the warm ones by a ratio of about 30 to 1. The goal of the receptors is to make sure that the body stays between 86 and 96 degrees Fahrenheit.
As I learned about thermoreceptors what was most interesting to me was things that the body does after it has been told that skin is either too warm or too cold. The body responds totally different depending on which one is occurring. When the brain is to that the body is cold it begins to promote heat gain and inhibit centers that promote heat loss. One example of something that promotes heat gain is shivering this is activated by the hypothalamus. When it is too hot the hypothalamus is also notified. The most effective heat fighting response that the body has is sweating so the body begins to do this.
All in all I believe that so much of what our bodies are able to do is down right amazing. The concept of thermorectors is definitely one of those things. To have an internal thermostat that is able to unconsciously do things to improve our quality of life is a very helpful thing. Our lives would be a lot different without thermoreceptors.
Key terms: epidermis, dermis, thermoreceptors, cold fibers, warmth fibers,
http://en.wikipedia.org/wiki/Thermoreceptors
http://dwb.unl.edu/teacher/nsf/c01/c01links/www.science.mcmaster.ca/biology/4s03/thermoregulation.html
http://www.britannica.com/EBchecked/topic/591718/thermoreception
http://www.hometrainingtools.com/skin-touch/a/1388/
http://en.wikipedia.org/wiki/Cutaneous_receptors
This specific assignment left me with a lot of possibilities for topics to choose from between all the chapters we have currently covered this semester. After skimming through the text book, I came across one term that I had found intriguing and wanted to go more in depth with. Almost all of my topical assignments thus far have been based on conditions where it does not specifically relate to me personally. I decided to continue this week’s blog in the same context. I wanted to go back and reemphasize the concept of agnosia. Agnosia was a term discussed in chapter four that dealt with the idea of perceiving and recognizing objects. Agnosia is defined as the inability to perceive and recognize objects despite the ability to see them. In most instances, agnosia is due to brain damage. More specifically, this occurs when a portion of the temporal lobe is lesioned. There are different types of agnosia, because this type of abnormality only affects one modality. The first type of agnosia I would like to expand on is visual agnosia. This particular form involves a deficiency in recognition of visual stimuli. It can be broken down into two subtypes: apperceptive and associative. Persons with apperceptive agnosia have the ability to identify contours still. On the other hand, individuals with associative agnosia have difficulty in naming objects. One specific form of associative agnosia is known as prosopagnosia. This is the inability to recognize faces. Individuals with prosopagnosia are able to recognize these features as faces, but cannot distinguish who the person may be. This is detrimental because they might not be able to recognize their own family members or friends even though they are able to readily identify other various types of stimuli in their environment. Another type of inability to recognize objects comes in the form of auditory agnosia. This is a deficit that affects the ability to recognize words or sounds in the environment. Similar to the effects of visual agnosia, this specific form takes away a particular sensory portion. It is also known as “pure word deafness”. The second URL found at the bottom of the page gives a more detailed idea of the concept of auditory agnosia. There was a case report done on a 51 year old man who suffered from this condition. There were studies conducted in order to help identify his responses to auditory stimuli and notable findings showed that reaction times to certain tones were much below the average, and called unusual. There was a much greater probability of determining the correct answers based on visuals of what he was seeing. There was some debate whether this type of agnosia is associative or apperceptive. According to this study, they concluded that auditory agnosia is more likely related to an associative form. The research was conducted by Henry A. Buchtel and John D. Stewart. There is also the possibility of color agnosia. This defines someone who is incapable of identifying color distinction. It is interesting because even though this may be they are still able to determine brightness. Hue, which is the chromatic aspects of color (or light) is not as difficult a task to identify, however. This is something that I enjoyed learning because it was new to my knowledge and helped give me a sense of this concept. Finally, I wanted to touch the concept of tactile agnosia. This was for the reason that we skipped over the chapter on the sense of touch. I wanted to elaborate on this concept to give a more knowledgeable stance on an aspect that has not been currently covered. Tactile agnosia refers to the inability to identify objects through touch. In some instances this persons with this form of agnosia are only objectified by one of their two hands. This is depending on where the lesion is on the brain. If the left hemisphere is affected then the right hand with be in deficit, and if the right hemisphere is damaged the left hand with be unable to identify these objects. With all the different forms of agnosia that occur I was able to grasp a better understanding of the condition and what it all entails. I personally believe this topic fits well within the context of sensation and perception because of the vast majority of sensation structures it encompasses. Agnosia has been seen throughout the text alone, and the information on the internet helped to identify all sorts of problems that are associated with this cause. The last two links are youtube videos that show a study of a man who has agnosia where he is trying to identify objects and their form. The visual is a great example of a first-hand look at how this affects people in a very different way.
http://en.wikipedia.org/wiki/Agnosia
http://www-personal.umich.edu/~gusb/Buchtel-Stewart.pdf
http://www.psych.ucalgary.ca/pace/va-lab/Visual%20Agnosias/colouragnosia.html
http://brain.oxfordjournals.org/content/119/5/1565.full.pdf
http://www.youtube.com/watch?v=rwQpaHQ0hYw
http://www.youtube.com/watch?v=T1qnPxwalhw
Terms: agnosia, lesion, prosopagnosia, hue, tactile agnosia.
I chose to do my topical blog on the phantom limb because I thought the video shown in class on Tuesday was very interesting. A phantom limb is the perceived sensation from a physically amputated limb of the body. This fits into sensation and perception because people with amputated limbs should not be able to feel a limb that is not there but they can because the brain still perceives it.
This occurs with approximately 60-80% of individuals with amputations. Often individuals may feel like their missing body part is awkwardly positioned and this causes them immense pain. This is caused by the nerves that would normally be connected to the limb.
Some individuals indicate that when they are talking their phantom limb will gesture as they talk, some describe itching sensations in their phantom limb, and some say that they are out of control of their phantom limb and find it very distracting and often painful.
Until recently treatments for phantom limbs often included further amputations of limbs, cutting sensory nerves leading to the spinal cord, or even removing the thalamus of the brain, which receives sensory signals from the body. These were almost always ineffective in treating a phantom limb and sometimes even made the issues worse. Other treatments now include, antidepressants, vibration therapy acupuncture, hypnosis, biofeedback, or massaging the stump.
A key researcher of the phantom limb Ramachandran, has developed many theories pertaining to the cause of the phantom limb in individuals. Ramachandran has linked phantom limb pain to cortical and peripheral mechanisms. He also developed his own treatment for phantom limbs, called the mirror in a box. This gave the individuals the perception that they were moving their limbs when in reality they were not. This was very helpful for individuals that were experiencing pain because their phantom limb was in an uncomfortable position. They were able to get their phantom limb out of that position when their brain perceived that their arm was moving. This tricks the somatosensory part of the brain into thinking there is still a limb there and that it is moving decreasing the pain, which I think is brilliant
In 2009 Lorimer and Moseley and Peter Brugger did an experiment using visual imagery to make their phantom limbs do impossible things. These experiments concluded that because there was no feedback from their bodies, they had modified their neural representation of their limbs.
The University of England used the same concept using virtual reality technology. The real limb is attached to a computer and then they see two limbs moving in the simulator. This in turn is said to relieve discomfort when the brain perceives two arms moving.
I think it is very interesting that our brains, #1 can experience such a thing as phantom pain, and #2 can be tricked into believing the limb is actually there to relieve the pain. I think it is amazing that this can be relieved with just a mirror and it is great that these individuals do not have to endure more invasive procedures to get relief.
Terms: Phantom limb, thalamus, somatosensory ,
http://en.wikipedia.org/wiki/Phantom_limb
http://www.youtube.com/watch?v=YL_6OMPywnQ
http://bja.oxfordjournals.org/content/87/1/107.long
The topic that I choose to research for this weeks assignment is synesthesia.
Synesthesia is condition where senses get mixed up. Some examples of this are being able to see color in sounds, see color in letters, or taste colors. the reason why I decided to research this topic is because I find it interesting. I want to know more about it and how it works. The first website that I consulted for more information is the CNN website. Here I found an article about how synesthesia, particularly being able to see color in sounds, could be genetic. This article discussed a study that was done on those who have this kind of synesthesia. They expected to find a single gene that synesthesia was linked to. However they found that there are at least 4 different genes that appear to have an involvement. This leads researchers to believe that discovering the cause of synesthesia will be a lot more difficult than previously thought.
The second source that I used for this assignment was an article that was printed in The Economist in 2000. This article focused on a little girl who associates a certain number with a certain color. She was having a hard time understanding math problems because she was trying to focus on the numbers and ignore the colors. She was also a participant in a study that was trying to figure out weather an external factor was needed to illicit the color response. The researchers had the girl partake in several different trials. After all of them were complete, they concluded that an external stimulus is not necessary for the color to appear.
The third article that I chose to read for this assignment was the original study that was sited in the previous article. At this link, you can find a more detailed description of the tasks that the girl had to complete and learn how the researchers came to their conclusion.
http://articles.cnn.com/2009-02-09/health/synesthesia.genes_1_synesthesia-brain-regions-visual-areas?_s=PM:HEALTH
http://www.mixsig.net/resources/articles/PaintingByNumbers.php
http://www.mixsig.net/resources/articles/FivePlusTwoEqualsYellow.php
Forgot to post this one Thursday
After having class on Tuesday, I really got interested in phantom limbs. The video that we watched was very interesting and informing. The problem I had with it was that I didn’t quite understand everything that was being said. Some of the terms were confusing so I decided to read more about phantom limb so I could get a better understanding of how it all works.
As we know, phantom limb is pain which can be mild to extreme that is felt in the area where a limb has been amputated. This is caused because nerve endings at the point where amputation occurred are still sending pain signals to the brain. Thus, the brain still believes there is a limb still. People with phantom limb often suffer through tingling, cramping, heat and cold sensations. Damage to nerve endings is often a reason for phantom limb. Random re-growth can lead to abnormal and painful discharge of neurons in the stump of the amputated area, and may change the way that nerves from the amputated limb connect to neurons within the spinal cord. There has also been evidence for altered nerve activity within the brain as a result of the loss of sensory input from the amputated limb. The bad part with phantom limb is the pain is generable chronic. Once pain develops it persists and rarely improves by medical treatments. Surgery of more of the amputated usual shows little results as well.
The body and brain are intricately involved in the perception of the physical self. One such treatment that was implemented by Dr. Ramachandran involved the patient looking in a mirror and placing their existing arm in a box. The illusion makes you think your existing arm is your phantom arm. He then told the patient to try and flex and relax his hand and arm. After two weeks of doing this the pain and phantom arm had disappeared. Doctors now believe the best treatment for phantom limb is experience. If we can teach our body to reconcile the physical experiences of the body with the mental image then gradually our body changes so can our mental image.
As I read this I find it hard to even believe this stuff even happens. I can’t grasp something that’s not real causing pain. Even thought I understand the science behind why this could be happening it still doesn’t sound like there really is clear evidence to what is causing this. It just crazy to read and see all the things are brain can do to us. It’s almost like we don’t have control over half the stuff that goes on.
Terms- Phantom Limb, nerve, spinal cord,
http://www.webmd.com/pain-management/guide/phantom-limb-pain
http://en.wikipedia.org/wiki/Phantom_limb#Phantom_limb_pain
http://www.npr.org/templates/story/story.php?storyId=101788221
After reading this chapter on Sound, I wanted to focus on music and tone psychology. I am very interested in all genres of music and this ties in with the class Psychology of Music that I took last summer. Music psychology and sound is very interesting because music is a huge part of our lives and in the lives around us.
The first article I found shows research on normal individual versus psychiatric patients on the perception of music. The results showed that the normal individuals had a different way to perceive music then those that were the hospital patients. This was concluded that the human auditory system varies and it is easier to hear music when there is a simpler and shorter sound stimuli. Music has many tones and pitches that allow an individual to focus on the beats. Music is a desired sound to most people, and has a different effect then regular “everyday sounds.”
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC400748/
The video I found is a relaxation video that is suppose to help the brain release stress and focus on the music. The music playing is very calming and is a part of a “music therapy” type of approach. Many people use self- therapies of music and meditation to help them become less anxious. I have personally used meditation techniques and music that had certain tones that have been tested to decrease stress. Music and the many different sounds “activates” parts of the brain that is pleasurable to most individuals. Sound and psychology is very interesting because many of us like with all sensation and perception it comes naturally and we take it for granted.
http://www.youtube.com/watch?v=_iFHjj3ruIA
The third article I found is an article about using different vocal tones to communicate with others. When a person is upset or happy their mood can be sought to out by the individual that you are speaking to. When a person identifies with a particular mood, their tone of voice matches that mood. Also, when a person is sad, they can “fool” you by using high tones to sound happier than they really are. The author goes on to suggest that in everyday life if you recorded your conversations with people you would be able to tell by the way you interact and speak to a person can ultimately show your mood.
http://www.psychologytoday.com/blog/happiness-in-world/201008/the-importance-tone
vocab: tones, music, auditory system, activates parts of the brain, meditation, sound psychology
As I had mentioned in my reading blog, I didn't enjoy chapter 12 as much as I thought I would. This was about touch, but it was way more technical than I usually like. But I chose to write my topical blog about phantom limbs. This topic is very interesting to me and even personal. My cousin lost part of his leg while in Afghanistan and they had to remove his leg above the knee. He would always tell us about phantom pains he would have in his leg. This is why I chose to write about this topic!
One of the first things I found interesting on the NYU website was that they define phantom limbs as being a syndrome. When I think of the word syndrome, I think of a disease, not a physical wound. That shocked me that they would define it this way and made me even more interested in what they had to say. This website gave some good insight as to reasons why people are more prone than others to receive this "phantom limb" sensation. I honestly thought that this was something that occurred in everyone who had an amputation. But this website states that the trauma related to the wound prior to the amputation can affect the sensation. Some of the things listed were the types of anesthesia used during the operation, a disease in the ligament removed or even the rapidness of the amputation procedure.
http://www.med.nyu.edu/content?ChunkIID=96857
I always like using the WebMD website because it gives plain and simple insight into the topic you are looking for. This helps my understanding because the topics are "dumbed" down so anyone can relate or understand what the topic is about. I like how they explained how this sensation occurs. Basically, the nerve endings from the amputated limb are still sending signals to the brain as if the limb is still there. This is the easiest explanation that I have found so far. I think that this sensation is so sad, especially for those in the military. They continue to have to feel pain in a body part that no longer exists and it can bring back so much trauma that it can be unbearable. This website also gave great insight as to how you can treat phantom limb sensations. I didn't know that this was something that could be treated, but the treatments are so simple that it makes sense!
http://www.webmd.com/pain-management/guide/phantom-limb-pain
*Side note. While looking through the internet to find articles, I found a phantom limb website that I thought might be interesting. Turns out, its a band. How creepy is that?
One of the first things I found to be super interesting in this article is that you can have a phantom organ. Not even just a limb. i have no idea what my organs feel like, but it would be crazy to still continue to feel pain after it has been removed! I have been in the hospital on and off in the last month with several infections and a failing kidney and I know how horrible the pain was/is in my side. I can't imagine experiencing that for the rest of my life. I couldn't relate to the pain in losing a limb, but knowing that it can happen to an organ, that hit home for me. I also learned on this website that phantom limb sensations aren't common at all. Only about 5-10% of people with an amputated limb experience this sensation. I was under the impression that all people with amputated limbs had this sensation.
http://www.news-medical.net/health/What-is-a-Phantom-Limb.aspx