Tuesday, April 28, 2009
(Evidence towards biological bases of anxiety disorders)
Selective Mutism is a widely misunderstood, ignored and under-researched childhood anxiety disorder:
The Child Who Would Not Speak A Word
Monday, April 20, 2009
Effect of Color on Cognitive Task Performance
In the recent University of British Columbia study, researchers Mehta and Zhu explored the differences between red and blue in relation to cognitive performance. Their study involved 600 participants who performed various tasks while looking at computer screens, which displayed red, blue or neutral backgrounds. In a task of word recall, they found that participants looking at words against a red screen had a higher rate of accurate word recall than those looking at the blue or neutral screens. In another task, Meha and Shu had participants think of creative ways to use a brick. While all groups had to think of the same number of uses, judges of the study later concurred that participants in the blue screen group found more creative uses for the brick than those in either red or neutral group. From their study, Mehta and Zhu found that the color red enhances performance on tests of recall and attention to detail, while the color blue enhances performance on tests requiring imagination.
Red Enhances Human Performance
In a related study at the Durham University of England, anthropologists Russell Hill and Robert Barton found that the color red enhances performance in competitive sports. As in nature where red is connected to testosterone and masculinity, in the human world male dominance can be influenced by the wearing of red. In their study of Olympic competitions, Hill and Barton found that wearing red is consistently connected with a higher probability of winning (competitors wearing red in boxing, tae kwon do, and wrestling defeated their blue-uniformed opponents about 60% of the time). This study suggests that the evolution of sexual selection, in which red symbolizes dominance, plays a role in human response to color.
In a study on male physical attraction to women at the University of Rochester, researcher Andrew Elliot and Daniela Niesta found that men who viewed photographs of women wearing red shirts perceived the women as more attractive and desirable, and were more willing to take them on a date and pay for the date, than women wearing blue shirts. Participants were not aware that the influence of color on attractiveness/attraction was being measured in the study, and they indicated that color did not play a role in their rating of the women.
Elliot and Niesta note that:
-Color is a common language within and across species
-The mere perception of color is sufficient to produce affect, cognition and behavior consistent with that meaning.
-Red carries meaning of sex and romance.
-Found in folktales, literature (The Scarlet Letter –Hawthorne), theater (A Streetcar Named Desire), red light districts and red lipstick (which has been used since Ancient Egyptians, 10,000 BCE).
-Red in animals, reddening during mating.
Color and Psychological Functioning
In another study on the effects of red by Elliot from the University of Rochester, he found that even an unconscious awareness of red in a testing scenario affects the ability of the test taker to perform. More specifically, he found that the presence of the color red during testing negatively affects performance. Elliot believes this effect is related to the meanings and specific information that red often conveys, such as a teacher’s red markings on an assignment or a red sign indicating danger. Interestingly, this study seems to contradict Hill’s study on red and Olympic competition. Elliot suggests that a distinction should be made between viewing and wearing red, for it is possible that viewing red caused the blue player to perform badly (as opposed to Hill’s theory that wearing red caused the red player to perform better.)
Finally, the influence of red, blue and yellow was measured in an experiment conducted by a group of interior designers. In this experiment three identical white rooms, each 18ft x 20ft x 10ft in dimension and containing a bar with twelve white bar stools and four white computers, were “bathed” in either red, yellow or blue light. Guests were then invited to attend a cocktail party in one of the three rooms. The results showed that guests in the yellow room consumed almost twice as much food and drink than those in the other two rooms. In terms of physical interaction, guests in the blue room occupied the perimeter of the space while guests in the red and yellow rooms were far more socially interactive with each other, forming small clusters in the middle of the rooms. These findings suggest that blue may induce more antisocial behavior than red or yellow, and yellow may increase appetite.
These studies on color point to the peculiar relationship between unconscious sensory perception and cognitive functioning.
“Color Study Looks at Effects of Red and Blue,” http://www.nytimes.com/2009/02/06/science/06color.html?emc=eta1
“Design: Spatial Color” http://www.contractmagazine.com/contract/esearch/article_display.jsp?vnu_content_id=1003685899
Elliot, Andrew & Marcus A. Maier. “Color and Psychological Functioning: The Effect of Red on Performance Attainment.” Journal of Experimental Psychology 136(1): 154-168.
Elliot, Andrew & Daniela Niesta. “Romantic Red: Red Enhances Men’s Attraction to Women,” Journal of Personality and Social Psychology 95(5): 1150-1164.
Hill, Russell A. & Robert A. Barton, “Psychology: Red enhances human performance in contests,” Nature 435 (293)
Mehta, R. & Zhu, R.J. “Blue or red? Exploring the effect of color on cognitive task performances,” Science 323(5918):1226-9.
Sunday, April 19, 2009
Friday, April 17, 2009
• The Itch is the most frequent complaint from dermatologists’ patients (Gieler & Walter 2008).
• Approximately 8 to 10% of the world’s human population suffers from chronic itching, medically known as neurodermatitis (Gieler & Walter 2008).
• In 2006 approximately 300 million people suffered from scabies, a skin disorder in which biting mites cause irritation and itchiness (The Lancet Infectious Diseases as cited in Miller 2007).
• Also in 2006, a study found that 42% of nearly 19,000 kidney-dialyses patients, representing 12 countries, reported a moderate to severe itch (Nephrology Dialysis Transplantation as cited in Miller 2007).
• In August 2007 an estimated 31.6 million Americans experienced skin itchiness induced by eczema (Dermatitis as cited in Miller 2007).
• The Fourth International Workshop for the Study of the Itch took place in San Francisco in April 2007.
The Itch as seen in the brain.
Scientists believe itching evolved as a survival tactic to ward off potential hazards such as insects by drawing attention to the vulnerable area. As Atul Gawande (2008) references in his article, the definition of The Itch, termed by physicians as pruritus, has not been replaced since 1660 when the German physician Samuel Hafenreffer referred to it as, “An unpleasant sensation that provokes the desire to scratch.” This definition addresses the two main components of pruritus: the negative sensation itself and our bodies’ instinctive treatment for it- scratching. Leknes et al. (2006) found that two types of itching, histamine and allergen-induced, both stimulated limbic and ventral prefrontal activation. The researchers go on to explain that the activation of both regions correlates with the individual’s desire to itch. In addition, the two areas are associated with motivation processing. Scratching offers an immediate reward. Although an individual may understand intellectually that scratching is not remedial in the long term, the brain can override this logic because it focuses on immediate rather than future rewards.
In terms of M.’s case, and any other patient suffering from chronic itching, the extensive circuitry involved in The Itch can be extremely problematic. Treatment must mitigate the sensation but also our motor response.
A study done at the Bender Institute of Neuroimaging at the University of Giessen in Germany used fMRI to show that histamine-induced itching did not activate the sensorimotor cortex, but rather areas of the frontal lobe, left temporal lobe and the left hemisphere of the cerebellum (Gieler & Walter 2008). Furthermore, research done by Handwerker evidences the stimulation of the amygdala and Hideki Mochizuki in Japan documented the activation of the cingulum, “a switching center that processes emotions, and the insula, an area also associated with emotion and disgust, both fire during itching-but not during pain” (Gieler & Walter 2008). The cingulum is a fiber tract of white matter, above the corpus collasum. In patients with neurodermatitis scratching does not inhibit the cingulum, thus The Itch is exacerbated by emotions (Gieler & Walter 2008).
The Itch versus Pain.
Historically, pruritus was considered as a lesser form of pain. This is known as the intensity theory (Gieler & Walter 2008). Both sensations travel from the periphery to the spinal cord along C-fibers. Less stimulation in C-fibers was believed to produce itchiness. If stimulation were increased the itchiness would turn into pain. As Gawande (2008) explains, The Itch is not a subset of pain, but rather an entirely separate sensation. Even so, it is interesting that because there are connections between itch and pain pathways, they influence each other (Gieler & Walter 2008); pain tends to quell itching, and painkillers tend to produce itchiness. (Miller 2007). In addition, scratching and rubbing offer momentary relief because they trigger pain and touch receptors, subduing pruritus (Gieler & Walter 2008). In 1997, Martin Schmelz, now working at the University of Manheim in Germany, declared that his research team had found C-fibers that did not react to painful heat or pinching, but was stimulated when histamine was injected into the skin of healthy individuals (Miller 2007). In addition, H. Erik Torebjork from Sweden reported that nerve fibers associated with itching are not myelinated. Thus, blocking electrical stimulation along myelinated nerve fibers will not stop the itching sensation (Perkins 1997).
Relieving The Itch.
Research for treatment for pruritus and neurodermatitis is ongoing. One promising drug is a blocker for gastrin-releasing peptide receptors (GRPR). A study done with mice shows the absence of the gene for GRPR results in mitigated itching. In addition, calming techniques such as autogenic training “(in which patients repeat a set of visualizations) and Jacobson’s progressive muscle relaxation (in which patients relax muscles to relieve tension), have proved effective in supplementing medical treatment” (Gieler & Walter 2008). Such treatments are logical knowing that stress is the second most prominent catalyst for itching. Allergens are first. Dalgard et al. (2006) found from a questionnaire that the 27% of subjects that reported itching were younger, generally female, non-Norwegian, were of lower-income, more distressed and undergone more negative life events and finally had poorer social support. In 1949 a study done by Dr. Cormia proposed that patients experiencing localized itching were suffering from family resentment. Electroshock therapy was suggested as treatment (Science 1949).
Following the experimental lecture, “Itching- what’s behind it?” Niemeier et al. (1999) surmises that itching can be alleviated by verbal and visual stimulation. The first half of the lecture featured “itchy” topics—pictures of fleas, mites, scratch marks on the skin, allergic reactions etc.—while the second exhibited more soothing topics—pictures of baby skin, soft down, bathers, mother with child in her arms etc. Video documentation shows more scratching, and by logical deduction increased itchiness, amongst audience members in the first half of the lecture.
This leads to the discussion of contagious itching being a product of mirror neurons, similar to yawning.
The majority of the research focuses on localizing pruritus, but what if, like in M.’s case, this proves impossible? What if, as Anne Louise Oaklander believed, The Itch had migrated from its proper nerve fibers and established a new loop? What if M.’s brain circuitry had gone haywire? Indeed our brain’s circuitry can go haywire very easily. Gawande (2008) mentions phantom limb; coinciding with phantom limbs is the transformation of somatotopic maps, or as Ramachandran (1998) refers to as “the remapping hypothesis.” and subsequently the projection of sensations to phantom limbs. For example, Ramachandran (1998) found in eight out of eighteen patients, tactile stimulation to the face results in stimulation of the phantom arm.
Ramachandran (1998) hypothesizes that the reworking of neuronal circuits does not entail creating new synaptic connections but rather revealing pre-existing ones. If this is indeed the case, the human brain is setup for remapping. To a certain extent, treatment for a circuit that goes awry is an attempt to mitigate the human brain’s innate plasticity.
Looking at phantoms...but first a little experiment.
Ramachandran & Rogers-Ramachandran (1996) explains that phantom limbs are the result of contradictory feedback; specifically, the motor intention to move a limb, is not reinforced by sensory, proprioceptive information. In normal individuals, the frontal lobe, controlling motor actions, communicates (sometimes via the cerebellum) with the parietal lobe. With each motor action, sensory information is attached. In phantom limbs that are rigid, to the point of paralysis, the brain has learned incorrectly that the limb is unable to move. This is where mirror therapy applies. Ramachandran & Rogers-Ramachandran (1996) constructed a virtual reality box, in which the patient perceives the phantom limb moving in the mirror, but in reality they are looking at the reflection of their existing limb. The patient is tricking his brain into receiving false proprioceptive information. With repeated mirror therapy patients are able to unclench fists, relieving pain, and in some cases the phantom limb has vanished.
Similarly, mirror therapy has been tried on patients with complex regional pain syndrome (CRPS). CRPS is similar to phantom limb pain in the sensations it induces- burning, cramping and mislocalized (McCabe et al. 2002). The “phantom” pain may exceed the original pain resulting from trauma, etc. McCabe et al. (2002) argues that similar to phantom limbs, CRPS results from incongruent feedback. In other words, the connection between sensory information and visual confirmation is disrupted. In early CRPS cases the mirror exercises was found to have analgesic effect, however, the mirror did not benefit those with chronic CRPS (McCabe et al. 2002).
Although the virtual reality box has proved affective, Murray et al. (2006) explains the box’s limitations: a narrow spatial dimension and the requirement that the patient only focus on the reflection and ignore the intact limb. He and is colleagues propose “Immersive Virtual Reality,” (IVR). Using a head-mounted display, patients visualize a virtual reality in which their intact limb is superimposed as their phantom limb. The research is in its initial stages but is promising. The researchers’ main concern is the argument that the IVR is a distraction versus a pain mitigator. Patients are required to complete four motor tasks that occupy their attention, distracting them from the pain.
Can mirrors combat The Itch? And further speculations.
At the end of Gawande’s (2008) article he mentions a conversation he has with Ramachandran, in which the neuroscientists suggests mirror therapy for M. There are obvious similarities with pruritus and pain. McCabe et al. (2002) explains, “The classical picture of a pain mechanism as a single hard-wired, dedicated pathway is no longer widely held. Instead, converging evidence from physiological and functional imaging studies suggests a much more diffuse and plastic system, involving the cord, brainstem, thalamus and cortex. In addition, psychological statues such as attention, anticipation and preparation for action may be inherent, essential components modulating the experience of pain.” Pain could be substituted with itch in the above quotation. In phantom limb patients, the brain learns the fixed position of the limb. In CRPS, the brain learns the pain, because it is not finding any relief. What if The Itch is learned as well? If the sensorimotor cortex is not activated at all, as found with histamine-induced itching, this can be even more problematic.
Referring back to M.’s case, the area of her scalp that itched was indeed numb. The specific nerves responsible for the Itch had been killed. However, with no relief (such as scratching) the brain eventually learns that that area of the scalp itches and will persist to itch. M. has yet to try mirror therapy, according to the most recent updates on her case. A couple self-prescribed mirror therapy to help with the husband’s Anesthesia Dolorosa, after reading Gawande’s (2008) article. Anesthesia is a complication from neurosurgery in which facial sensation is reduced to pain (facial-neuralgia.org 2006). The husband was given Neurontin, which alleviated some of the pain from Trigeminal Neuralgia, contracted in 1997. However it had a dual-depressant affect, which had to be counteracted with stimulants such as caffeine, methylphenidate, (Ritalin) and Dexedrine. The husband developed a tolerance and subsequent addiction to the stimulants, as well as cardiac problems. He had to stop using any of the medications, including Neurontin, however, the pain was too severe. The couple decided to try mirror therapy at home and found it was extremely successful. The wife considers it a miracle.
At the present time research is being done to locate the specific modalities of pruritus, however, it seems that The Itch is part of a much larger conceptual issue; the brain is adversely susceptible to its on plasticity. A virtual reality, whether it is using a mirror or a computer, must counteract the reality that exists in our brain, separate to the external world, and idiosyncratic to each individual.
“All-over” Itching May Spell Family Resentment (1949). The Science News-Letter, 56,
25. Retrieved on April 4, 2009 from, http://www.jstor.org/stable/3927072
Anesthesia Dolorosa (2006). Facial Neuralgia Resources. Retrieved on April 16, 2009
Dalgard, F., Lien, L., Dalen, I. (2007). Itch in the community: associations with
psychosocialfactors among adults. Journal of the European Academy of Dermatology and Venereology, 21, 9.
Gawande, Atul (2008). The Itch. The New Yorker. Retrieved on February 11, 2009
Gilier, Uwe, Walter, Bertram (2008). Chronic Itching: Causes and Cures/ How to get
relief from the insatiable need to scratch. Scientific American. Retrieved April 17, 2009 from, http://www.sciam.com/article.cfm?id=chronic-itching
Leknes, Siri G., Bantick, Susanna, Willis, Carolyn M., Wilkinson, John D., Wise,
Richard G., Tracey, Irene (2006). Itch and Motivation to Scratch: An Investigation of the Central and Peripheral Correlates of Allergen- and Histamine-Induced Itch in Humans. Journal of Neurophysiology, 97. Retrieved on April 15, 2009 from, http://jn.physiology.org/cgi/content/abstract/97/1/415
McCabe, C.S., Haigh, R.C., Ring, E. F. J., Halligan, P.W., Wall, P.D., Blake, D.R.
(2003). A controlled pilot study of the utility of mirror visual feedback in the treatment of complex regional pain syndrome (type 1). Rheumatology, 42. Retrieved April 15, 2009 from, http://rheumatology.oxfordjournals.org/cgi/content/full/42/1/97
Miller, Greg (2007). Grasping for Clues to the Biology of Itch. Science, 318.
Murray, Craig D., Pettifer, Stephen, Howard, Toby, Patchick, Emma L., Caillette,
Fabrice, Kulkarni, Jai, Bamford, Candy (2007). The Treatment of phantom limb pain using immersive virtual reality: Three case studies. Disability & Rehabilitation. Retrieved on April 14, 2007 from, http://dx.doi.org/10.1080/09638280601107385
Niemeier, V., Kupfer, J., Gieler, U. (2000). Observations during an Itch-Inducing
Lecture. Dermatology Psychosomatics, 1. Retrieved on April 17, 2009 from, http://content.karger.com/ProdukteDB/produkte.asp?Doi=57993
Parker-Pope, Tara (2008). Dr. Gawande Answers Questions About ‘The Itch.’ The New
York Times Well. Retrieved on April 15, 2009 from, http://well.blogs.nytimes.com/2008/07/04/dr-gawande-answers-questions-about-the-itch/?scp=1&sq=tara%20parker%20itch&st=cse
Perkins, S. (1997). Scientists finally find where to scratch. Science News, 152.
Ramachandran, V.S. (1998). Consciousness and Body Image: Lessons from Phantom
Limbs, Capgras Syndrome and Pain Asymbolia. Philosophical Transactions: Biological Sciences, 353, 1377. Retrieved on April 15, 2009 from, http://www.jstor.org/stable/56900
Ramachandran, V.S., Rogers-Ramachandran (1996). Proceedings: Biological Sciences.
Retrieved on April 15, 2009 from, http://www.jstor.org/stable/50718
Tuesday, April 7, 2009
Monday, April 6, 2009
From their pool of volunteers Yang and Raine interviewed and tested participants and separated them into three groups: 12 adults whom they classified, according to certain criteria, as regular ‘liars;’ 21 normal, relatively honest adults; and 16 adults with antisocial personality disorder but no history of pathological lying. The liars targeted in the study were those with histories of manipulative and conning behavior and malingering (lying about ones health for personal gain). Yang and Raine then examined the volunteers’ brains using magnetic resonance imaging and found a considerable discrepancy between the grey/white matter ratios of the liars and of the two control groups. Liars showed 14 percent less gray matter in their prefrontal cortex than the normal individuals, but had 26 percent more white matter than the antisocial subjects and 22 more than the normal subjects. The Liars also exhibited a prefrontal gray/white matter that was much lower than both control groups.
White Matter comprises 40-50% of the volume of a normal adult brain. It is a network made up of millions of axons that facilitate connections between the nerve cells (grey matter) in different parts of the brain. According to Dr. Sean A. Spence, Professor of Psychiatry at the
Though this study focuses on just one part of the neural circuitry involved in lying, it raises many crucial questions about the potential of white matter connectivity, about the definition of “pathological lying” and different kinds of deceptions, about structural abnormalities as causes or affects of behavior, and about the relationship between neurological development and ones proclivity to lie.
"Radio Lab: Into the Brain of a Liar." Radio Lab. Narr. Robert Krulwich. National Public Radio.
6 March 2008
Spence, Sean A. "Prefrontal white matter -- the tissue of lies." The British Journal of Psychiatry. 187 2005: 326-327.
Yang, Yaling and Adrian Raine. "Prefrontal white matter in pathological liars."The British Journal of Psychiatry. 187 2005: 326-327.