What
I would like you to do is to choose any topic related to any aspect of Sensation & Perception 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 Sensation & Perception, 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 was very interested in learning about the nose in chapter 13. I had a septoplasty 2 years ago due to my nose being broken a few times, and hit several other times. The cartilage in nose was tilted so far to the right that I could barely breathe through that nostril, and suffered from chronic congestion. After the surgery and recovery, I am now able to breathe through my nose very well, and my sense of smell even seemed to improve. I think it’s interesting that each person’s nose is shaped differently but yet they usually serve the same function effectively.
The external nose consists of paired nasal bones and upper and lower lateral cartilages. Internally, the nasal septum divides the nasal cavity into a right and left side. The lateral nasal wall consists of inferior and middle turbinates, and sometimes a superior turbinate bone. The opening of the sinuses also is found under the middle turbinates on the lateral nasal wall. The lacrimal system drains into the nasal cavity below the anterior inferior portion of the inferior turbinates.
In contrast to vision and audition, but similar to touch and taste, the olfactory system is attached to an organ that serves another purpose. The primary function of the nose is to filter, warm and humidify the air that humans breathe. Inspired air is brought high into the nasal cavity to come in contact with the olfactory nerves, thereby providing the sense of smell, which is intimately associated with the taste sensation.The inside of the nose has small ridges that add turbulence to incoming air, called turbinates, causing a small puff of each breath to rise upward, pass through a narrow space (olfactory cleft) and settle on a yellowish patch of mucous membrane called the olfactory epithelium. The olfactory epithelium is at the back of each nasal passage, approximately 2.75 inches up from the nostril, and is the “retina of the nose.” Each epithelium measures about 1 to 2 square inches and contains three types of cells: supporting cells, basal cells, olfactory sensory neurons (OSN’s). OSN’s are the main cell type, and are small neurons located beneath a watery mucous layer on the epithelium. The cilia on the OSN dendrites contain the receptor sites for odorant molecules (olfactory receptors).
The interaction between an odorant and the olfactory receptors stimulates a cascade of biochemical events, ultimately producing an action potential that is transmitted along the axon of the OSN to the olfactory bulb. In order to initiate an action potential, 7-8 odor molecules must bind to a receptor and it takes about 40 of these nerve impulses for a smell sensation to be reported. Olfactory nerve endings originate in the olfactory bulb under the frontal lobe and pass directly through the cribriform plate as second-order neurons entering the nasal cavity. Olfactory nerves are found on the superior portion of the septum, superior turbinates, and cribriform region.
The third, fourth, and fifth links listed below have helpful illustrations of the external and internal portions of the nose to better understand how smells enter our body and are perceived by our body and brain.
I enjoyed learning about the anatomy and physiology of the nose and appreciated the gained knowledge because I now have a greater understanding of how my body/brain perceive the smells around me to assist in identifying particular objects, people, restaurants, and even some events-like the Iowa State Fair.
Sources:
http://emedicine.medscape.com/article/874771-overview#
http://emedicine.medscape.com/article/874771-overview#aw2aab6b3
http://www.chop.edu/healthinfo/anatomy-and-physiology-of-the-nose.html
http://maggiesfarm.anotherdotcom.com/uploads/noseetc.gif
http://www.google.com/imgres?imgurl=http://www.baileybio.com/plogger/images/anatomy___physiology/11.powerpoint_-_respiratory_system/nose_2.jpg&imgrefurl=http://www.baileybio.com/plogger/%3Flevel%3Dpicture%26id%3D711&usg=__M3e5DGiuOTM_XpCdp9xjydL8vFQ=&h=450&w=534&sz=43&hl=en&start=17&zoom=1&tbnid=sTBzWZIg0l6DFM:&tbnh=111&tbnw=132&ei=NoKLT4qeNc7oggfxuPnhCQ&prev=/search%3Fq%3Dphysiology%2Bof%2Bthe%2Bnose%26um%3D1%26hl%3Den%26sa%3DN%26rlz%3D1T4ADFA_enUS426US428%26tbm%3Disch&um=1&itbs=1
Terms: nose, cartilage, septoplasty, nostril, congestion, smell, vision, audition, touch, taste, olfactory system, organ, turbinates, olfactory cleft, mucous membrane, olfactory epithelium, nasal passage, retina of the nose, supporting cells, basal cells, olfactory sensory neurons, OSNs, cilia, dendrites, receptor sites, olfactory receptors, action potential, axon, olfactory bulb, nerve impulses, inspired air, nasal bones, upper and lower lateral cartilages, nasal septum, nasal cavity, lateral nasal wall, inferior turbinates, middle turbinates, superior turbinate bone, sinuses, lacrimal system, olfactory nerve endings, frontal lobe, cribriform plate, septum
After reading chapter 14 I found a lot of topics of interest. I love food so this chapter was extra fun to read. One of the things that I wanted to focus on for my topical blog was a supertaster. A supertaster is a person with sensitive taste buds, most specifically to bitter or salty flavors. Most supertasters have ultra taste buds that can even pick out ingredients of something they eat. There are 3 main types of tasters out there. Supertasters, medium tasters, and non- tasters. People who have non-taste buds don’t actually lack a sense of taste but their taste buds are dampened in comparison with other groups, especially when it comes to bitter and sweet tastes. An example of this is that many non-tasters don’t taste the bitter aftertaste of saccharine (which is a bitter sugar) that many medium and supertasters don’t like. Supertasters have such a strong sense of taste that they actually taste sugar at least twice as sweat as a non-taster would. Supertasters also tend to taste coffee, kale, Brussels sprouts, broccoli, and cabbage as particularly biter. They also feel more pain and irritation on their tongue from things like spicy foods and carbonated water. Studies have shown that around 25% of people are said to be non-tasters, 25% supertasters and 50 % medium tasters. Women and Asian people are more likely to be supertasters.
The cause of being a supertaster is still unknown. Many speculate that it is due to the increased number of fungiform papillae on the tongue. These papillae are located on the top of the surface of the tongue. They’re scattered throughout the filiform papilla but mainly at the tip of the lateral margins of the tongue. These papillae can distinguish between sweet, sour, bitter, salty and umami. There is no clear evolutionary advantage to supertasting.
Another interesting fact about supertasters is that some are found to be slimmer than other kids of tasters. Tuft University found women who are supertasters were 20% slimmer than non-tasters and medium tasters. Taste plays no role in our eating habits but a big role in what we actually eat. A big advantage for super tasters is they usually don’t need a lot of salty or sugar foods in their diet. Salt is a lot more appealing to supertasters because it can block the bitterness of some foods if ate alone. Americans in general eat far more sodium per day than health guidelines recommended. Supertasters with high sodium diets over time could be at risk for high blood pressure, heart disease, and other health problems. Another problem is children who are supertasters. They don’t like to try certain foods so it’s hard to get kids to eat healthier. The best way to increase the amount of healthier foods in a child’s diet is to put little amounts of the food in every meal to get them used to it. Often change up the menu so there’s variety as well. The reason I found this so interesting is because I know a lot of supertasters and I never really understood why they hate trying different kinds of foods. After reading everything I did it makes much more sense why they tend not to like certain foods. I’ll Probably get off their back a little bit on trying different foods now.
Terms- filiform papilla, supertaster, medium taster, non-taster, fungiform, salty, bitter, sugary, sour
http://www.harvardhealthcontent.com/QuirkyBody/129,QB111510
http://www.bbc.co.uk/science/humanbody/body/articles/senses/supertaster.shtml
http://voices.yahoo.com/what-supertaster-they-6266812.html?cat=5
http://www.cnn.com/2010/HEALTH/06/16/salt.taste/index.html
http://en.wikipedia.org/wiki/Supertaster
I decided to talk about supertasters for my topical blog. Essentially supertasters are more able to taste the four taste sensations more prominently. SS. Stevens was the one that found out about supertasters and started doing tests on them. He decided to look at a new genetic variation in taste, instead of measuring thresholds, investigators could look now at a suprathreshold taste and plot the psychophysical functions showing how perceived taste intensity varies. Two of SS. Steven’s students, Joseph Stevens and Lawrence Marks, made another amazing discovery that humans are very good at cross-modality matching. This is when someone has the ability to match the intensities of sensations that come from different sensory modalities. This ability enables insight into sensory differences. To the average taster the bitterness of the coffee bean roughly matches the pain of a mild headache, for a supertaster, the bitterness of the coffee roughly matches a very severe headache. Those supertasters with the most fungiform papillae not only experience the most intense taste sensations in general, but also experience the most intense sensations of oral burn and oral touch because fungiform papillae are innervated by nerve fibers that convey burn and touch sensations, as well as those that convey taste sensations.
Linda Bartoshuck was the one who coined the term. She has spent much of her career studying genetic variation in taste perception. In the early 90’s, Linda and her colleagues noticed that some individuals tested in the laboratory seemed to have an elevated taste response and took to calling them supertasters. Supertasters were initially identified on the basis of the perceived intensity of propylthiouracil or PROP compared to a reference salt solution. However, because supertasters have a larger sense of taste than medium or nontasters, this can cause scaling artifacts. Subsequently, salt has been replaced with anon-oral auditory standard. That is, if two individuals rate the same physical stimulus at a comparable perceptual intensity, but one gives a rating twice as large for the bitterness of a PROP solution, the experimenter can be confident the difference is real and not merely the result of how the person is using the scale.
TERMS: supertaster, psychophysical functions, cross-modality matching
http://en.wikipedia.org/wiki/Supertaster
http://supertastertest.com/
http://www.todayifoundout.com/index.php/2010/06/how-to-tell-if-you-are-a-supertaster/
Phantom Limb! What an interesting topic, I thought, so I researched it more. Phantom limb is something that a 90 percent of amputees experience. While researching this topic, I discovered that is much more than just the feeling of a amputated limb being present, is actually pain, felt by the limb that was once there. It has been said that there is no cure for this problem, but doctors have recently come up with something called "mirror therapy".
Mirror therapy is when a patient with an amputated arm or leg, holds up a mirror to the none amputated limb and looks into the mirror at the arm or leg and your neurons actually fire as though the limb in the mirror is their amputated limb! When one get's their leg or arm amputated, what causes phantom limb is when your visual perception of your amputated limb conflicts with the nerves in your leg. The nerves are sending a message to your brain that the leg hurts, when in reality, it isn't even there. Your brain can still feel the leg.
So, the mirror therapy helps one's visual perception see a leg or arm in the reflection. While looking at the leg or arm in the mirror, the patient will move the leg around, and they will report that they can actually feel like they are moving the amputated arm or leg! CRAZY!
One study was done with 3 groups of 6 people. One group did mirror therapy for 4 weeks, another did covered mirror therapy (where the mirror was covered with a filmy fabric), and the last group closed their eyes, imagining moving their amputated leg again. All three groups measured their pain throughout their 4 weeks of therapy. The mirror therapy came up on top with 100% of the subjects feeling less to no pain after the therapy. 1 subject in the covered mirror therapy felt less pain, and 2 in the mental-visual group. This study shows that the mirror therapy really does work! This is a great step forward for phantom limb pain.
Terms: phantom limb, neurons, visual perception.
http://www.nejm.org/doi/full/10.1056/NEJMc071927
http://www.youtube.com/watch?v=YL_6OMPywnQ
http://www.medicinenet.com/script/main/art.asp?articlekey=88097
When reading the chapter about Touch, I read about the perception of pain. For more extreme situations, we all feel pain, but some of us have a high tolerance for pain, which in itself is rather interesting. What is pain though, pain is an unpleasant sensory and emotional experience associated with actual or potential issue damaged, like burning a finger, being poked with a needle. Though most people do not enjoy pain, and don’t like experiencing, pain does have a purpose. Pain is made to motivate an individual to withdraw from the damaging situation, protect the injury and avoid the same or similar situation. Functions as a warning sign that there’s something wrong with our bodies and thus leading us to go to the doctor’s office to see if something is wrong. It’s a useful defense mechanism that our body had developed.
There are also different kinds of pain, I’ve always thought of pain as pain, but there are different types like neuropathic, phantom as in the phantom pain from phantom limbs, incident and etc. I wasn’t aware that there were different kinds of pain. Nociception is the sense of pain, a sense of perception in itself. Nociceptors send signals to the neurons and those signals continue on to the spinal cord, which travel quick or slow depending if the neurons are coated in myelin. The signal is sent then to the brain and from then a signal is sent to the limb or area for us to retract the limb. All that done in a split second or so, amazing how fast they work considering what they have to do and the travel they have.
But I had prior knowledge that there are rare occasions that people don’t feel pain. There may be in some instances where there’s a distraction for like athlete while playing. But there are two more permanent disorders that deal with pain perception; pain asymbolia, and congenital insensitivity to pain. Pain asymbolia, also called pain dissociation is categorized by the inability to recognize the unpleased or disagreeable component of a painful/threatening stimulus. They feel it, but there is no defense reaction to said pain, even able to describe the pain as sharp or hard, but still report that it didn’t hurt. Congenital insensitivity to pain is a very rare disease, its characterized as a dramatic impairment of pain perception since birth. The source being hereditary sensory and autonomic neuropathies involving smaller-caliber nerve fiber that normally transmit nociceptive inputs along sensory nerves. These people do not fell any measure of pain. Due do the lack of these means of defense against injury and illness, though some with this disorder may reach adulthood they are not expected to live very long. Individuals with this rare illness often engage in harmful behaviors that result in damaging their tongues, eyes, skin, muscles etc. Often are kept in hospitals and institutions that can keep an eye on them and prevent as much damage as possible.
So as much as we may dislike feeling pain, it’s actually very helpful to have it. And for those that do not feel pain, it’s not as good of a situation as we would think.
Terms: pain, nociceptor, pain asymbolia, congenital insensitivity to pain
http://en.wikipedia.org/wiki/Pain
http://andy-luttrell.suite101.com/the-neurology-of-pain-perception-a163555
http://www.psych.ndsu.nodak.edu/nawrot/Courses/465Projects10/Pain/FinalProject_files/Page724.htm
Tropical Blog
I decided to research why bad smells make people gag. This was interesting to me because I have just always wanted to know why my body has this reflex due to the fact that it seems to happen to me quite often. This fits into both the taste and smell chapters in the book because this reflex accesses portions of both sense for sensation & perception.
When searching for the answer to this question I discovered that there may be caustic chemicals in these odors that make humans gag. A single cell in our nose may be able to detect these chemicals with one single whiff. These caustic chemicals allegedly alert the brain of danger.
This leads me to my next topic of acquiring taste which is something that humans are better at then most species of animal. Koalas for instance only eat eucalyptus plants and are very picky about their freshness. This is why they are also nearly extinct. When you compare these animals with humans, who can adapt to taste nearly anywhere it shows why it is so easy for us to survive in harsh or lush climates.
Humans eat some pretty weird things such as fermented duck eggs and moldy cheese, which is exactly what researchers had people eat for a little experiment. When we try something new for the first time we have a much different response than if we have eaten it many times. This reflex helps small children and adults to be responsive to possible situations where a person could be poisoned. The human body is most in tuned to needing salt and sugar which is why small children love these tastes rather than sour or bitter taste. In addition to this fascinating information I also learned about super tasters. Scientists can look at a person’s tongue and put blue food coloring on it and then use an ultra violet light to determine if they have a large amount of taste buds compared to the average human. This leads scientists to believe that people all have different taste experiences and have a threshold for the amount of tastes they are able to acquire.
Another interesting experiment that I saw was with wolves. They had the wolves attack and eat a sheet that they had poisoned. The wolves essentially got food poisoning from the fresh meat. You could tell because the wolves soon after eating it started vomiting. Surprisingly the response was so powerful that the wolves did not eat sheep, one of their favorite meals, for over 1 month.
On a funny note I found a list of the top ten things that make people gag due to the harsh smell. Enjoy; 10 Fat Man Poo, 9 Sulfur, 8 Dog poo, 7 fart, 6 rotten eggs, 5 Body odor, 4 Girls Perfume, 3 Dog fart, 2 vomit, 1 Eviscerated decomposing body.
Web links
http://www.abc.net.au/science/articles/2008/03/05/2180489.htm
http://www.cornel1801.com/bbc/HUMAN-SENSES/Smell-And-Taste.html
http://www.the-top-tens.com/lists/top-ten-worst-smells.asp
terms: reflex, odors, cell, caustic chemicals, acquiring taste, and threshold.
For my topical blog i decided to research anosmia. I wanted to research this further because it is always interesting when something is not functioning properly. Anosmia is when olfaction is not happening properly, or the lack to smell odors. Anosmia can also be specific to only certain smells while still being able to smell others. This is called specific anosmia. Anosmia can be temporary or can be permanent. Doctors often diagnose anosmia by using a acetylcysteine test. People can self diagnose anosmia by the use of over the counter smelling kits. Anosmia can be caused by a number of things including nasal polyps, smoking, schizophrenia, tumors in the frontal lobe, old age, or head trama. It can also be caused by a previously common over the counter cold remedy called Zicam. Common side effects associated with the loss of smell can include loss of libido, feeling of depression, and the inability to detect harmful sents such as gas. People with anosmia often also find food less appatizing because 90% of taste is smell. There is no treatment for permanent anosmia but patients often receive therapy similar to others that have lost the sense of hearing or sight.
While researching anosmia, I came across some other intersting smell problems such as phantosmia. This is when people perceive a smell that is not being produced by anything. This is can be caused by seizues in the temporal lobe, alzheimer's, or schizophrenia. Phantosmia can sometimes be treated transnasal surgery.
http://en.wikipedia.org/wiki/Anosmia
http://en.wikipedia.org/wiki/Phantosmia
http://www.huffingtonpost.com/bonnie-blodgett/anosmia-the-quiet-killer_b_648971.html
Terms: anosmia, olfaction, odors, specific anosmia, temporal lobe, frontal lobe,
I chose to do my topical blog on Tadoma because it was something I had never really heard of it and I thought it was interesting. Tadoma is a method of communication that can be used by deaf and blind people.This relates to the chapter because it deals with our ability to communicate though touch when we do not have other senses to be able to do so. This is sometimes referred to as tactile lip-reading. The person places their thumb on the person speaking’s lips and the palm of their hand and fingers across their jaw and cheeks. Vibrations and movements of the jaw and vocal chords can be picked up through the speaker’s throat and jaw line by the “listener’s” hands. Some sounds feel alike on the speaker’s lips, however the vibrations on the throat feel differently allowing the listener to decipher what the person is saying.
If the deaf/blind person knows sign language the other hand is used to place the sign into. This gives the listener a better chance to understand what the speaker is saying and also to reinforce the movements and vibrations the person is detecting with the hand on their face. This could help the individual retain their speech skills that they had before going deaf or blind and could also help them learn to communicate words themselves. The person learning Tadoma can feel the other persons face, throat and lips and then feel theirs replicating movements and vibrations in their own face, throat and lips. This is a difficult form of communication to learn to use, but can be beneficial in certain circumstances, like dual sensory impairment. Fluent Tadoma users have the ability to comprehend up to 40 words per minute.
Sophie Alcorn in the 1920s developed Tadoma at the Perkins school for the Blind. This was developed because it was thought that if students only learned to sign they would have no interest in ever learning to speak. In the 1950s Tadoma began to become less and less popular, because of it’s difficult and time consuming to learn. There are currently only about 50 users of Tadoma worldwide. American sign language is much more commonly used. However Tadoma can be very beneficial to individuals who are deaf/blind and can take the time to learn the skill.
Terms: Tadoma
http://en.wikipedia.org/wiki/Tadoma
http://www.lifeprint.com/asl101/topics/tadoma.htm
http://www.youtube.com/watch?v=U_QMS-hzRMs
http://www.sfsu.edu/~cadbs/Eng005t.html
http://www.asel.udel.edu/icslp/cdrom/vol3/1002/a1002.pdf
I decided to do more research on taste buds and super tasters. This fits into sensation & perception by the subject of taste and how we perceive certain flavors. I’m interested in dentistry so anything that has to do with our oral hygiene interests me. Taste factors into oral hygiene because dentist must understand how patients are able to taste certain flavors. Something new I learned after reading this chapter was something called a super taster. A super taster is an individual who experience taste with a higher level of intensity than an average person would experience taste. It is more common to find this in females than in males.
We unfortunately do not have a known cause for why some people may taste things more intensely than others however we can speculate that it is due to an increase number of fungiform papillae. It is also unclear as to why we have continued to have this advantage throughout evolution. There are certain foods that supertasters are more prone to tasting more intensely. These tastes include alcoholic beverages, cabbage, coffee, green tea and carbonated beverages. Taste is extremely important so we are able to taste certain flavors. For example, our 4 main flavors are bitter, sour, sweet and salty. It is thought that we are wired to tell the difference between the four due to our past ancestors having to detect poisonous food.
Did you know that on average a human has between two thousand to eight thousand taste buds? Taste buds are located around a small structures on the tongue, esophagus, epiglottis and soft palate. These taste buds are referred to as papillae. When an individual starts eating, food is dissolved in saliva that comes in contact with a taste receptor. The taste receptors sends the information that is received to the gustatory areas of the brain via the seventh through tenth cranial nerves.
Terms: taste buds, super tasters, fungiform papillae, esophagus, epiglottis, soft palate, tongue, papillae, taste receptor, gustatory.
http://en.wikipedia.org/wiki/Supertaster
http://www.vivo.colostate.edu/hbooks/pathphys/digestion/pregastric/taste.html
http://en.wikipedia.org/wiki/Taste_bud
After reading chapter 14 I became interested in supertasters. I wanted to find what the pros and cons were of being a supertaster. Also what exactly makes you able to be a supertaster. This concept is very fascinating to me, and I think it would be really cool if I was a supertaster.
So what exactly is a supertaster? A supertaster is someone who tastes food a bit different than others. The tastes for a supertaster are a more intense than they would be for someone with no (non tasters) or medium taste. The phenomenon was first discovered by A.L. Fox who was a chemist. In his lab, by mistake he found that some people could taste phenylthiocarbamide (PTC) and others could not taste anything. The taste that was observed was a bitter taste. Now when we test to see if someone is a supertaster we use propylthiouracil (PROP), this is similar to PTC but much safer. It is believed 25% of people taste nothing when they are around PROP, 50% are medium tasters, and 25% are supertasters.
It has been said that women are more likely to be supertasters. Also along with women being more likely to be supertasters, Asians and African Americans are also more likely to be supertasters. There is really no reason why these individuals are more likely to be supertasters. Also there really hasn’t been much information found on why people are supertasters. Research suggests that supertasters come from our genetics. People may be supertasters because they have a higher number of fungiform papillae, which is where some of our taste buds are. The most heightened taste for a supertaster is bitterness.
I was really interested in the health issues of being a supertaster, because when you initially learn what a supertaster is you don’t really think of the consequences, it just seems like something really cool to have. After I spent some time researching supertasters I found that there are some pros and cons about being a supertaster.
The advantages of being a supertaster are one, your diet. A supertaster is more likely to be healthy and not over weight. This is because they are in a way more of a picky eater, some unhealthy foods do not taste the same to supertasters. Supertasters do not like high sugary foods or fatty foods. This also makes them less likely to get cardiovascular diseases. Second, supertasters are less likely to drink alcohol and to smoke. These tastes do not taste good to them. Because most alcohol has a bitter taste, it is heightened in supertasters. Although most alcohol does not taste good to supertasters some do like, beer because some supertasters are more attracted to carbonated beverages.
The disadvantages of being a supertaster are, it is suggested that they may be more likely to develop colon cancer or other cancerous diseases. This is because supertasters do not like to eat vegetables. Vegetables have a bitter taste to them so many supertasters avoid eating vegetables. The bitterness of theses vegetables acts as a protector from these diseases. Also other research has found that supertasters may be more likely to put salt on their foods, which can cause health risks. Supertasters do this because salt acts as a mask to the bitterness taste, it covers it up so they cannot taste it.
After I finished researching supertasters I still think it would be pretty cool to be a supertaster. You would experience tastes in a completely different way than others. Also the tastes would be way more intense, which would cause you to really like certain foods and not like other foods at all. It seems to me that the disadvantages of being a supertaster are not too harsh, so the risks aren’t that high if someone were to be a supertaster. The advantages outweigh the disadvantages.
Terms: supertaster, non tasters, phenylthiocarbamide (PTC), bitter, propylthiouracil (PROP), fungiform papillae, taste buds
http://en.wikipedia.org/wiki/Supertaster
http://supertastertest.com/
http://www.cnn.com/2010/HEALTH/06/16/salt.taste/index.html
I chose to write my blog post about phantom limb this week. When we watched the movie in class last week, I was so intrigued by this phenomenon that I went home and researched it. I had never heard of phantom limb, so naturally I wanted to find more information.
Phantom limb is a condition experienced by a person who has lost or is missing a limb in which there are still sensations in the missing limb. This happens in 60-80% of individuals with amputated limbs. Unfortunately, phantom limb is a serious problem in the medical community because it is often a painful experience for an individual. The “limb” is often twisted and formed in uncomfortable and painful ways and the person is not able to control the actions of the phantom. In addition to extreme pain, individuals with phantom limb feel as though they are able to use their phantom as they would normally. For example, in a study by Dr. Ramachandran asks individuals to pick up a coffee cup using their phantom and when they “reach” for the cup, he pulls it away. Not only did the individual try to pick up the cup with the phantom, but also when the cup was pulled away he exclaimed that it hurt to have it ripped out of his “hand”. This is an interesting example of how the person experiences the sensation of touch and pain in something that does not exist. There have been several different sensations reported in phantom limbs, such as sensitivity to temperature, itching, and burning. The limb is also typically a different shape or size than a normal arm. Some patients report that their phantom arms are shorter or longer than their other arms. In addition to phantom limb, there are also phantom pains. Phantom pains can occur in someone who was born without a limb or in those who are paralyzed. They are similar to phantom limb, but they concern a larger portion of the body.
The original explanation for phantom limbs was that severed nerves had an effect on this condition. Then when the nerves were severed, the brain recognizes the inflammation as pain and thus the explanation of the phantom limb. It was until recently that this theory was challenged. The new theory is that the brain undergoes reconstruction once a limb is removed, particularly in the somatosensory cortex. This is the area of the brain that received input from the limbs. This theory was back up by an experiment linking nerves in the face to nerves in the hands. Researchers found that there were specific nerves in the cheek that directly influence the fingers, even a phantom finger. When these areas were aroused, then the person is able to feel it in their fingers. Researchers found a very distinct map connecting different nerves in the face to nerves in the hand, or perceived nerves rather. Many argue that touch is a perceptual experience, that cannot be replicated.
Initially, it appeared as though treatments for phantom limb were exhausting and not working. The early treatments for this phenomenon consisted of severing the damaged nerves on the stump, and thus making a new stump. This not only created new problems and pains, but it didn’t get rid of the phantom limb itself. In extreme cases, the sensory nerves in the spinal cord and the thalamus would be removed-both not yielding positive results. Now, the current treatment consists of a mirror box. In this treatment, patients are asked to look at this box, and it creates the illusion that their working hand is their phantom hand and when they see the working hand and they control it, they are able to control their phantom. This has shown positive results, but as with any therapy, it takes time for this system to work. This treatment not only helps to reposition the phantom, but to relax the phantom from being tight and awkward. Mirror treatment has yielded beneficial, long term results for these patients.
Terms: Phantom limb, sensations, spinal cord, thalamus, mirror box, somatosensory cortex.
http://www.phantomlimbcompany.com/
http://www.webmd.com/pain-management/guide/phantom-limb-pain
http://en.wikipedia.org/wiki/Phantom_limb
For this week's topical blog I chose to do a post on sweetness, but not in the way you might expect. In my preliminary research I came across a fascinating fruit that temporarily alters how we taste food! The berry, Synsepalum dulficum (also known as the "miracle fruit"), contains a protein which attaches itself to taste buds and causes sour fruits to taste sweet. This protein, called miraculin, is thought to distort the shape of sweetness receptors, thereby causing them to respond to acids instead of sweet substances until the miraculin is washed away by saliva. This effect can reportedly last anywhere from half an hour to two hours, depending on how long the miraculin stays bound to the tongue.
Though miracle fruit has been known to its native West Africa for hundreds, maybe even thousands of years, it was not discovered by the western world until the 18th century. Since that time, it still did not receive much notoriety until a biomedical postgraduate student by the name of Robert Harvey happened upon it in 1960. Harvey instantly saw the fruit's potential as a healthy alternative to sugar and founded a company to grow the fruit in the Caribbean, extract the miraculin in Massachusetts, and sell it across the entire United States. In addition to a dietary product, he expected the product would revolutionize food consumption for diabetics. However, this dream came crashing down in 1974 when the Food and Drug Administration banned production of the product, classifying it as a food additive that needed several more years of safety testing. Many suspect that this ruling was handed down in response to pressure exerted on the FDA by large sugar corporations, who would clearly have the most to lose if miraculin hit the market. The decision is especially questionable when you consider the fact that miracle fruit has been consumed by Africans for hundreds of years without any known adverse effects.
Since this time, miracle fruit has largely been forgotten once again. However, in some underground circles, people still participate in rituals known as "flavor tripping". This is when a bunch of friends gather and indulge in a smorgasbord of food, tasting them like they never have before! It remains to be seen whether any companies can manage to get the FDA to reconsider their decision. Given the prevalence of obesity across our nation, this sort of product would no doubt provide great benefits to the general public health.
Miracle fruit relates directly to our textbook because it further complicates the issue of how exactly sweetness is perceived by our taste buds. We know that one receptor is responsible for the perception of all sweetness, but it was not quite clear from the articles I read whether miraculin interferes with the function of all the other receptors or if it merely causes the sweetness ones to be triggered at inappropriate times. As most people know, it is not difficult to tell the difference between sugar and artificial sweeteners (and people often prefer the natural taste, though they can condition themselves into liking saccharin or aspartame better). However, in many of the sources I consulted, it seems the sweet taste induced by miraculin is actually preferred to sugar hands down! This could mean that Americans could actually be persuaded to prefer the healthy alternative, instead of consuming the artificial sweeteners that have been rumored to provide empty calories and lead to increased weight gain in the end! Either way, it is fascinating how even when we think we know so much about a perceptual topic, something like this can come around and turn everything on its head. I think that is the important thing to remember for me - perception is very context-specific. We must remember that how we perceive the world can quickly be altered by something as simple as a protein...and then it's back to the drawing board.
http://news.bbc.co.uk/2/hi/uk_news/magazine/7367548.stm
http://en.wikipedia.org/wiki/Synsepalum_dulcificum
http://www.nytimes.com/2008/05/28/dining/28flavor.html?_r=1
Terms: Synsepalum dulficum, miracle fruit, miraculin, taste buds, sweetness, flavor tripping, sugar, saccharin, aspartame
Supertasters were what I decided to do further research on for a couple of different reasons. The first reason is because I think that out of the three different levels of tasting this would be the most irritating to me. Studies have shown that 25% of people are nontasters, 25% supertasters, and 50% are medium tasters. As far as taste goes for me I think that I am in the middle. I think that to be a supertaster would be the toughest because you cannot turn down taste but others can find ways to turn it up. Another thing that made me interested in supertasters is my friend who claims that he has geography or geographic tongue.
The term supertaster is a term that was coined by Linda Bartoshuk who is an experimental psychologist. Supertasters are individuals who experience the sense of taste with a greater intensity than normal. This is something that is more common in women then men. Although the cause is not known for why this occurs it is believe that supertasters possess more fungiform papillae than normal. Some believe that being able to be a supertaster is an evolutionary trait that served as a defense mechanism for the body. What I wanted to learn the most about was the food that had big impacts on supertasters. I was especially drawn towards hotter foods like the book discussed. Researching this made me thing about my friend who claims that he has geographic or geography tongue.
My friend tends to claim that he has a lot of conditions so I am usually pretty skeptical when he gives me the name of something he has. When I was typing in geography tongue I doubted that there even was such a thing. I did find it however. Geographic tongue is an inflammatory condition of the tongue. It is said to only affect 2% of the population so this does not make me believe my friend anymore that I already did. The cause of this condition is unknown. What happens when an individual has this is that papillae missing from parts of the tongue. Most of time having geography tongue is unnoticeable to the individual with it but, contact with certain foods can cause burning or swelling of the tongue. Those foods may be spicy, sour, or sharp. Although the jury is out on my friend I think that the condition of geography tongue is very interesting. Since there is no clear cure for it and it may be genetic I am interested see if he may pass it on to his children (if he has it).
Key terms: Supertasters, geography tongue, papillae, fungiform papillae
http://www.mayoclinic.com/health/geographic-tongue/DS00819/METHOD=print&DSECTION=all
http://ysm.research.yale.edu/article.jsp?articleID=77
http://www.bbc.co.uk/science/humanbody/body/articles/senses/supertaster.shtml
http://en.wikipedia.org/wiki/Geographic_tongue
http://en.wikipedia.org/wiki/Supertaster
I chose the topic of tracing a scent. After reading chapter 13 I wanted to know more about the differences between humans and animals and how species track scents. Scent plays a big part in how we live. When we eat our tongue only really tastes sweet, salty, sour, and bitter. Anything beyond those four is all due to olfaction or our sense of smell. But before looking at how humans and other animals track scents, you first have to know how a scent is tracked.
One of the first things I found interesting was the (apparent) debate on how long a scent will linger. Few people apparently believe that scents can stick around for (at the very most) a year. But a better guess that I was able to find was four weeks under good conditions. ‘Good Conditions’ being an area with little wind, a lot of vegetation such as grass and bushes and cool temperatures. Wind can disperse a scent making it very hard to follow. The surrounding vegetation and temperatures are key to tracking a scent because the scent will cling better to vegetation and will be lower to the ground on cool days. During warmer weather, scents will rise higher off the ground and are harder for animals to catch the trail of. When studied, it was found that people take shorter breaths through their noses and compare scents by intensity.
Even as a kid I always found sharks interesting and loved to learn about them. With the topic of scent I was able to look at how sharks use their olfaction. People have to inhale a scent into their nose to expose it to the receptor cells allowing us to recognize it as a scent. Sharks use their nares (shark version of nostrils) to pick up scents in the water. Sharks don’t actually ‘breath’, instead they keep their mouth open and the water passes through their mouth and out of their gills (where the oxygen is taken out of the water). This same process is used in the nares but instead pick up scents instead of oxygen. Shark’s amazing scene of smell comes from the multiple chemoreceptors lining the shark’s nares. Because there are so many, they are able to pick up around 13 molecules in one liter of water. Making it possible to track pray even when it is ¼ of a mile away. More research has yet to be done, due to the fact that many sharks are studied in the ocean and experiments are somewhat of a problem to conduct at times if the conditions are not perfect.
Websites:
http://www.livescience.com/2737-surprising-impact-taste-smell.html
http://www.missingpetpartnership.org/petdetective-scent.php
http://news.sciencemag.org/sciencenow/2006/12/18-02.html
http://www.elasmo-research.org/education/white_shark/smell.htm
Terms: olfaction, nares, and chemoreceptors.
After looking through the various chapters, I decided I wanted to find a topic that I haven’t read or learned about yet, so I skimmed through chapter thirteen on olfaction. I had always heard about pheromones and thought this would be the perfect term to do my research on the internet. There were a couple concepts that I believe must first be discussed in order to understand pheromones. The first is olfaction. Olfaction refers to the sense of smell. Without this, the sense of pheromones would not be present. In some instances, very few, there is the possibility of anosmia. This is also referred to as smell blindness. Anosmia is a total and complete lack of the ability to smell. Two primary causes of anosmia include a form of injury to the head or sinus illness. Another concept that is important in relation to olfaction is known as the olfactory sensory neurons. These are the cells found in the olfactory epithelium beneath a mucous layer. They contain receptors for odorant molecules. With these couple of ideas I found that I was able to grasp a better sense of some background information before I jumped into my search on pheromones. With a little information from the beginning of the chapter I was able to more easily look into and understand the section of vomeronasal organ and pheromones. There are two important subdivisions in animals who survive through the use of smell. One is the main olfactory bulb. This is an extension of the brain that is found slightly above the nose. This is the area where smells are processed. In humans, they give a different name where they call it only olfactory bulbs. The other subdivision is known as the accessory olfactory bulb. This is a smaller neurological structure. It is found behind the main olfactory bulb. According to the dynamics of anatomy found in the accessory olfactory bulb there needs to be an engaged structure, known as the vomeronasal organ, which is activated. The vomeronasal organ, VNO, is a chemical sensing organ. This particular organ is important for my concept of pheromones. It involves an evolutionary detection of chemicals that cannot be processed by the olfactory epithelium. Pheromones, to be specific are not odors, but rather chemicals in which may or may not have smell. Pheromone is a word comprised of Greek wording. It is thought that pheromones are emitted and triggers a response in another person or member of that species. These responses are either physiological or behavioral. Even without smell they produce a chemical form of communication. There are various forms of pheromones including alarm, food trail, and sex. I found my particular interest in pheromones because of the information I had heard based on sex pheromones in humans. Vertebrates and plants are also thought to communicate through the use of pheromones. There is some history dating back to the first discovery of pheromones in silkworms. A German research team extracted the perceived pheromone compound while simultaneously removing extraneous matter to determine a response. There was some debate whether this would prove accurate amongst mammals because of their uniquely different characteristics and independent nature. Other research has found that there is a connection through the VNO in mammals when they removed the VNO and compared it to responses without the removal. The particular study I am referring to was conducted on hamsters. Another idea I found interesting regarding scents, and in particular pheromones, was women and menstruation. According to research done by Dr. Winnifred B. Culture of Philadelphia, men are important to women. Besides the long known existence of pheromones in animals, Women with longer or shorter menstrual cycles become more close to a regular cycle after the presence of male pheromone. Similarly, women who live together or exposed to one another regularly, menstruate at the same time. Also, noted was that women who have sex at least once a week with a male have more regular menstrual cycles. They also have fewer menopause and fertility problems, which helps to support pheromone exposure.
Terms: olfaction, anosmia, olfactory sensory neurons, main olfactory bulb, accessory olfactory bulb, pheromone, vomeronasal organ(VNO)
http://en.wikipedia.org/wiki/Olfaction
http://en.wikipedia.org/wiki/Pheromone
http://www.hhmi.org/senses/d230.html
http://www.athenainstitute.com/discovery.html
This week I chose to look further into change blindness. I was able to find 2 sites with a lot of information anda 3rd site is a link to a demonstration of a flicker test which I'll talk about later. The demonstration was pretty interesting. I play a lot of photo hunt games where I have to find the differences between 2 pictures, it's not very difficult if they are next to each other. But if you have to look at the pictures separately the task difficulty increases dramatically. Try it out and see how you do.
"Change blindness is the failure to notice a visual change in our field of view". Change blindness can occur even when the change in a scene is large, constantly repeated or known to the observer. Once the observer knows that the change is occurring it is extremely obvious when looking again. The idea that focused attention is needed to see a change can explain change blindness. If attention is not given to the point of change than it can easily go by without being noticed. This idea shows that change blindness can be a useful way to study visual attention and that our "conscious experience of a scene does not involve a representation in which all events are faithfully represented; instead, representation of objects and events may be created on a just-in-time basis by the careful management of attention".
There are two different theories of change blindness. The two theories are known as the top-down hypothesis and the bottom-up hypothesis. The two theories refer to what it is about the change of the scene that gets our attention. In the bottom up hypothesis it is focused on the visual salience of image components. This includes the basic elements of our visual processing such as movement, lighting, and contrast. The top down theory focuses on our "understanding of the context of a scene". For example, if you are looking at a picture of an office and are told to find the computer you're attention will most likely be focused on the desk because we understand that it's where the computer will probably be. With change blindness both of these theories do seem to be working together. We use top down knowledge to focus on things of interest in the scene (the computer) but at the same time our attention can be easily refocused on a change in lighting or with movement. When we focus on these 2 things it's easy to miss changes elsewhere in the scene. We only have so much visual and cognitive processing resources. Therefore it is easier to miss changes if we are not focusing on the specific object that is changed.
Researches have been looking at change blindness for many years. Recently, researchers are arguing that prior research on change blindness was contaminated by unintentional changes. These researchers created a computer algorithm to make changes to a picture without making changes to the overall visual salience of the scene so they can better separate the two variables. The researchers used a flicker test which is showing a scene taking away the scene and then showing the same scene again with one change. Past research showed that it is more difficult to see the changes when there is a gap in between the scenes then when one scene is immediately followed by the changed scene. The final link I'll post shows an example of a flicker test that you can try for yourself. The researchers showed that people are more perceptive to changes involving removing or replacing objects that they are to objects changing colors.
A closely related phenomenon that is often confused with change blindness is inattentional blindness. "This is the failure to experience an object or event that is easily seen once noticed". This generally occurs when you are focusing on an attentionally-demanding task and you do not expect the event or object. The two forms of blindness are similar but change blindness involves second-order information (the transitions between quantities) and inattentional blindness involves first order information (the presence of quantities). The two refer to different aspects of the visual world. Other aspects of change perception that can be distinguished are detection (determining that a change has been made), identification (determining what kind of change was made) and localization (determining where the change was made). There is also the ability to determine what item changed. Failures in each of these visual aspects have ben found, change blindness generally refers to the failure to detect the change.
Link to example of inattentional blindness: http://www.youtube.com/watch?v=Ahg6qcgoay4
Information about change blindness:
Check out the first two links on this website, they're both good
http://theness.com/neurologicablog/?p=2061
http://www.scholarpedia.org/article/Change_blindness
This website has a demo to test change blindness.
http://www.gocognitive.net/demo/change-blindness
TERMS: change blindness, top-down hypothesis, bottom-up hypothesis, lighting, contrast, visual saliance, innatentional blindness, second-order information, first-order information, detection, identification, localization
For this topic discussion, I chose to research the relationships between memory and perception. The relationship in itself is paradoxical; your perception affects memory, and your memory affects perception. Your perception is what is stored into memory. On the other hand, your memory affects what you attend to and what you ultimately perceive. The relationship between perception and memory is very complex and intimate; and in turn, these two concepts play a major role in the whole of your consciousness. Therefore, any insights into the relationship between perception and memory give insight to consciousness itself.
Memory is almost a stored copy of perception, but that does not necessarily mean it is true to reality. You perceive what is previously known. If you sense something unique to anything you have experienced before, your perception will associate it with what it has most in common with. Your memory will not only store the perception, but the association as well. The relationship between perception and memory is so strong that it is hard to decipher where the association takes place. Your perception could just be the attended sensation and memory is where the stimulus is associated with previous connections.
This seems to be a fitting end to the topical discussions in this class. Sensation and Perception may dictate and control your present self, attention given to the most novel stimuli, but the storage of memory creates most of who you are; your connectome. Every human being is comprised of two complicated systems of individuality. The first is your genome, which you may know as your entire genetic code. This is what creates individual proteins and makes up your physical self. The other part is your connectome, which are your individual connections between all neurons. Just like genetics, most people have similarities, important neural tracts. However, there are small differences that create the individual. A basic example of this would be your idea of love. Most people share a general definition of love, but small differences create individual perspectives. My concept may be similar to yours, because we both have loved someone before, but our experiences with this emotion have created a specific connectome that is individual to ourselves. Our connectome is our mental fingerprint that has been created by having independent perceptual experiences.
Terms: relationship between memory and perception, genome, connectome
http://dl.acm.org/citation.cfm?id=1162418
http://academics.tjhsst.edu/psych/oldPsych/memory1/percep.html
http://en.wikipedia.org/wiki/Connectome
http://www.ted.com/talks/sebastian_seung.html
I chose to write about the perception of a phantom limb, since a friend of mine lost his entire arm in Afghanistan during the war. He told me about his feelings after his arm was gone. He felt as if his fist was constantly being clenched as tight as possible. He would try grabbing for things without realizing it wasn’t there. It has been about seven years ago, and these feelings have now subsided.
A phantom limb is the sensation of feeling like a missing limb is still attached to the body and is moving. It is said that about 60 to 80 % of these amputees feeling these sensations and can be very painful. This pain can worsen with stress, anxiety or weather changes and can decline after time. The pain is sometimes described as a burning sensation, squeezing, tightness, tingling, cold or itching and can vary with each individual. The activity of sensory neurons and conscious experience is related to how the brain constructs a body image and is not fully aware of the altered connections.
It is often assumed that the phantom pain is a feeling of mind over matter. The brain’s perception is tricked into an optical illusion. It may be a form of mental denial and provides a mental image doesn’t follow the change in the body. The brain must reconcile the physical experiences of the body and the mental image has to be remapped.
The most successful treatment may be time. The pathways from the skin to the brain transmit the signals in touch. Pain may be altered by Chinese acupuncture using light touch or tapping. These sensations send signals directly to the central nervous system. Pain pathways in the nervous system have stopovers in the brain. Damage to the stopovers can make you feel pain when you shouldn’t.
Terms- phantom limb,sensation, sensory neurons, brain, and the central nervous system.
http://www.npr.org/templates/story/story.php?storyId=101788221
brain.oxfordjournals.org/content/121/9/1603.full.pdf
http://en.wikipedia.org/wiki/Phantom_limb#cite_note-RamachandranHirstein1998-2
After reading the chapter on perceptual development, I wanted to research more on videos and stories on infants world of vision.
1. The first video I found was a team of Positive Science Inc having a computer analyze infants eye movements and a camera on there head. The findings showed that the infants only looked at their mothers half of the time to get “approval to play” and only around 13% of the time would look at their mothers face. The video discussed how this was a great finding because infants are not looking at their mothers as much as researchers thought in the past. The infants would have a body coat on with a camera on there head and computer to know where they are looking at and how there eyes look to objects and determine where to go in the room full of toys. This was interesting to see because the babies looked uncomfortable during the experiment wearing the harness and other things on their head.
http://www.youtube.com/watch?v=aLWMFRvVed0
2. The second article I found discuss how infants use perceptual information to collaborate with their motor skills. Movements of the arms and eyes are important when the infants are learning to crawl and eventually walk. This is also important when the infant is recognizing objects and things around them. There was an interesting fact in this article stating that by the age of 3 and a half months, the infants have made between 3 to 6 million eye movements during their awake times. Infants are very curious and they will use their perceptive skills to gain knowledge of foreign objects and touching things around them. Eventually the infants will recognize facial expressions and more motor skill development because of their visionary system.
http://www.cde.ca.gov/sp/cd/re/itf09percmotdev.asp
3. The third article I found focuses on the different methods behind studying perceptual development in infancy. The first method of preference method is interesting and common knowledge because infants tend to look at stimuli that they find interesting and desirable. Infants will focus their attention on objects and ignore other perceptions. The second method of habituation is when they have adapted to a stimulus and then choose to look at another object. The infants get “used to” viewing a particular object and then tend to focus on another object around them. The third method is conditioning because it can be “learned” to view and know objects. Then finally there are research methods purposed to analyze brain activity in infants to understand the approaches and know which part of the brain is active during visionary process.
http://www.skidmore.edu/~hfoley/Perc14.htm
In conclusion these three websites provided more information on infancy perception that was provided in the book. I was thankful that I found a video that showed a research technique they use with infants to show viewers what they do to understand this concept. However, I would like to talk to child psychologists and ask their opinion on infancy research and how they think it is possible to receive a valid result.
vocab: habituation, conditioning, stimulus, methods, visionary process, motor skills
For this topical blog, I decided to look into look into anosmia. I chose this topic because I didn't read chapter 13 in the book about smell and I decided to learn something about the perception of smell!
I used the WebMD website again to give me a brief definition of what anosmia is. Anosmia is the complete loss of smell. I honestly thought it was that you lost the ability to smell certain things, not everything. That would be so crazy. This reminds me of one of my two-year-olds favorite books to read at daycare: The Nose Book. At the end of the book, it talks about how awful it would be if you didn't have a nose. My kids always make sniffing sounds and tell me what they are smelling at that moment because they DO have a nose. Anosmia is like my kids' book coming to a reality, and that is a scary thought. One other interesting fact is that anosmia can be temporary in people who have severe colds. It is not always a lifetime issue.
http://www.webmd.com/brain/anosmia-loss-of-smell
I always liked looking at the Mayo Clinic website because it gives different looks at definitions, symptoms and other topics about specific disorders. Through this I learned that a complete loss of smell is very rare, but it is quite common to lose your sense of smell for a short period of time. I also like that it said one of the biggest issues with losing your sense of smell is that you lose your sense of appetite and start not eating like you used to. It is funny to me how your sense of smell can affect so much in the body. I thought it was interesting that anosmia can be cause by several different things other than blockages in the nose or other common infections (flu, colds, etc). This article mentions that one of the ways anosmia can become permanent is through damage to your brain. I really didn't think of that before but this makes a lot of sense.
http://www.mayoclinic.org/symptoms/loss-of-smell/basics/definition/sym-20050804
This website was very informational and I loved how it was set up. I wish that I had found it earlier because it does a great job at describing what anosmia truly is. This website had some great facts about anosmia. One of my favorites was that 60% of older adults lose their sense of smell at one time or another. I also liked how they said that anosmia is almost like an invisible disability that really messes with the mind.
http://www.monell.org/anosmiahope/#skills