Fusiform Face Area

Faces are among the most important visual stimuli we perceive, informing us not only about a person’s identity, but also about their mood, sex, age and direction of gaze. The ability to extract this information within a fraction of a second of viewing a face is important for normal social interactions.  We have recently learned about fusiform face area which is a region of the brain that plays a major role in face perception.  Fusiform face area engages both in detected faces and determining the perceptual information to recognize them.  Ever since I was young I was very good with recognizing people and names no matter how long ago it may have been since I have last seen them and also am very good at reading people’s emotions although they may believe they are hiding them.   I found it interesting in the fact that such a small part of our brain plays the role in identifying not only faces but places and things as well. 

Can you feel that?

Can you feel that??

Congenital Analgesia or Congenital Insensitivity to Pain

Congenital Analgesia is a rare condition where a person cannot feel and has never felt physical pain which originates from the time of birth.  For those with this disorder, cognition and sensation are normal which means they can still feel discriminative touch (not always temperature) with no physical abnormalities.  This condition could result in the individual unintentionally harming him or herself, or in an injury being made worse by the individual not realizing its severity due to the inability to detect such an injury.  There have only been about 100 cases reported since 1932 when the first case appeared of a man who acted as a human pin cushion.  The exact cause of the condition is unknown.  Some cases, the cause is due to an increased production of endorphins in the brain whereas in other cases, the cause is due to a mutation in the sodium channels or integral membrane proteins in the brain although the nerves appear to be normal and functioning properly in the majority of cases.  The condition is believed to be hereditary since the frequency of passing the disorder onto an offspring is more often seen.  There are two types of congenital pain indifference: (1) Insensitivity to pain - is no perception of pain at all, (2) Indifference to pain – can perceive stimulus but lacks an appropriate response.  Treatment of a disorder involves developing an awareness of the condition and learning to regularly monitor oneself for injury.  Close monitoring is required especially during childhood to reduce the risk of accidental self-injury. 

http://www.youtube.com/watch?v=1vLsZ_dXFAg

Can you feel that??

Congenital Analgesia or Congenital Insensitivity to Pain

Congenital Analgesia is a rare condition where a person cannot feel and has never felt physical pain which originates from the time of birth.  For those with this disorder, cognition and sensation are normal which means they can still feel discriminative touch (not always temperature) with no physical abnormalities.  This condition could result in the individual unintentionally harming him or herself, or in an injury being made worse by the individual not realizing its severity due to the inability to detect such an injury.  There have only been about 100 cases reported since 1932 when the first case appeared of a man who acted as a human pin cushion.  The exact cause of the condition is unknown.  Some cases, the cause is due to an increased production of endorphins in the brain whereas in other cases, the cause is due to a mutation in the sodium channels or integral membrane proteins in the brain although the nerves appear to be normal and functioning properly in the majority of cases.  The condition is believed to be hereditary since the frequency of passing the disorder onto an offspring is more often seen.  There are two types of congenital pain indifference: (1) Insensitivity to pain - is no perception of pain at all, (2) Indifference to pain – can perceive stimulus but lacks an appropriate response.  Treatment of a disorder involves developing an awareness of the condition and learning to regularly monitor oneself for injury.  Close monitoring is required especially during childhood to reduce the risk of accidental self-injury. 

A Life Without Pain

The Process of Taste

How We Taste

            Taste is our gatekeeper to the enjoyment of food.  It also helps us to determine which substances we should consume and which we should avoid.  A person has approximately 10,000 taste buds with each bud containing 50-100 taste cells, which have tips that protrude into the taste pore.  Taste buds are generally replaced every 10 days.  Most are on the tongue but some are located in the back of the throat.  Grouped together in bumps or papillae on the surface of the tongue, the taste buds contain receptors that respond to four basic tastes: sweet, salty, sour, and bitter.  The number and density of taste buds a person has determines the sensitivity to each taste.  This is also known as being a taste or non-taster.  Normally, a greater response is found in more bitter substances.   Each receptor responds most strongly to one or two of the four basic tastes and slightly to the others.  The taste cells work together to generate a unique pattern of electrical signals that are transmitted to the brain for each substance tasted.  When a person tastes, chemical stimuli produce connections in the brain stem in the nucleus of the solitary tract are acquired from fibers found on the tongue, mouth and throat.  These signals then travel to the thalamus and extend to the frontal lobe (insula) and the frontal operculum cortex.  The sense of smell often works in conjunction with our sense of taste by combining sensations to achieve the perception of flavor. In fact, the olfactory sense actually contributes more to the perception of specific flavors than does the sense of taste.

The ‘geusia’s

            Could you imagine not having the ability to taste?  Ageusia is a disorder of the chemosensory organ of taste.  This is when a person has no ability to taste due to the tongues loss of function to taste or feel any taste.  Since smell and taste go hand in hand, this person may have also lost their sense of smell.  The tongue can only feel the texture and therefore the person feels the taste of the flavor only after both sense organs (nose and tongue) function properly.  Ageusia is a very rare condition whereas most patients suffer from hypogeusia whereas there is a loss of taste sense causing reduced intensity or dysgeusia which is a distortion of taste and the inability to differentiate between tastes (mistake salty for sour).  Causes of these disorders are primarily due to damage of the nervous system.  This would entail damage to the nerves of the tongue (lingual  and glossopharyngeal nerve).  Other causes could be multiple sclerosis and infectious conditions.