Synesthesia - Revision history

Emartinez at 06:07, 5 May 2008

Emartinez — Mon, 05 May 2008 06:07:37 GMT

←Older revision		Revision as of 06:07, 5 May 2008
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	[[Category:Neuropsychological syndromes]]		[[Category:Neuropsychological syndromes]]

-	Synesthesia is a neurological ~~syndromein~~ which stimulation of one sensory modality automatically and uncontrollably triggers another sensory modality. The types of synesthesia discussed in class include:	+	Synesthesia is a neurological syndrome in which stimulation of one sensory modality automatically and uncontrollably triggers another sensory modality. The types of synesthesia discussed in class include:

	#Color-graphemic synesthesia: written letters induce vivid color experiences		#Color-graphemic synesthesia: written letters induce vivid color experiences

JGasparri at 04:44, 5 May 2008

JGasparri — Mon, 05 May 2008 04:44:42 GMT

←Older revision		Revision as of 04:44, 5 May 2008
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	Synesthesia can also be a learned association. Witthoft and Winawer (2006) describe a case study in which their patient had a learned color-letter association as a byproduct of having colored refrigerator magnets as a child. Interestingly enough, this case also described the possibility that synesthetic color-letter associations can transfer between letters; their patient moved to Russia at the age of three, and her color-graphemic synesthesia transferred to Russian Cyrillik.		Synesthesia can also be a learned association. Witthoft and Winawer (2006) describe a case study in which their patient had a learned color-letter association as a byproduct of having colored refrigerator magnets as a child. Interestingly enough, this case also described the possibility that synesthetic color-letter associations can transfer between letters; their patient moved to Russia at the age of three, and her color-graphemic synesthesia transferred to Russian Cyrillik.
		+
		+	Alternatively, synesthesia may arise through "disinhibited feedback" or a reduction in the amount of inhibition along feedback pathways. Normally, the balance of excitation and inhibition are maintained. However, if normal feedback were not adequately inhibited, then signals coming from later multi-sensory stages of processing might influence earlier stages of processing, such that tones would activate visual cortical areas in synesthetes more than in non-synesthetes. In this case, it might explain why some users of psychedelic drugs such as LSD or mescaline report synesthetic experiences while under the influence of the drug.

	== References ==		== References ==

AlecTroeger at 02:06, 29 April 2008

AlecTroeger — Tue, 29 Apr 2008 02:06:29 GMT

←Older revision		Revision as of 02:06, 29 April 2008
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	Synesthesia often begins in early childhood, but it can be brought about as a result of brain injury or sensory dedeafferentation.		Synesthesia often begins in early childhood, but it can be brought about as a result of brain injury or sensory dedeafferentation.

-	Most of the time, synesthesia is unidirectional (for example, most colored-hearing synesthetes do not hear sounds when they see colors). ~~Also, even~~ if patients have the same form of synesthesia, it is unlikely that their concurrents are the same~~, meaning~~: letters will not produce the same colors to different synesthetes.	+	Most of the time, synesthesia is unidirectional (for example, most colored-hearing synesthetes do not hear sounds when they see colors). Even if patients have the same form of synesthesia, it is unlikely that their concurrents are the same: letters will not necessarily produce the same colors to different synesthetes.

	== Color-graphemic ==		== Color-graphemic ==
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	== Colored-hearing ==		== Colored-hearing ==

-	In colored-hearing synesthesia, sounds produce an extrasensory experience of color. This is usually in response to tones or other aspects of sound. ~~Usually, the~~ sounds that produce colors in colored-hearing synesthetes are musical sounds, or environmental sounds (such as alarm clocks, or birds chirping). ~~Like in~~ color-graphemic synesthesia, activation in V4/V8 has been associated with the experience of color in response to music or environmental sounds.	+	In colored-hearing synesthesia, sounds produce an extrasensory experience of color. This is usually in response to tones or other aspects of sound. The sounds that produce colors in colored-hearing synesthetes are musical sounds or environmental sounds (such as alarm clocks, or birds chirping). As with color-graphemic synesthesia, activation in V4/V8 has been associated with the experience of color in response to music or environmental sounds.

	== Number → Color & Shape ==		== Number → Color & Shape ==

-	In (number)→(color/shape) synesthesia, the patient will project numbers in front of themselves in, for example, a ~~coloured~~ arc.	+	In (number)→(color/shape) synesthesia, the patient will project numbers in front of themselves in, for example, a colored arc.

	== Time → Location ==		== Time → Location ==

-	In (time)→(location) synesthesia, the patient will arrange periods of time in a colored shape. For example, they may conceptualize the months of the year into a flat, horizontal loop surrounding them~~, and~~ each month ~~being a different~~ color.	+	In (time)→(location) synesthesia, the patient will arrange periods of time in a colored shape. For example, they may conceptualize the months of the year into a flat, horizontal loop surrounding them in which each month has its own color.
-		+
	== Causes ==		== Causes ==

Daveecee at 06:42, 27 April 2008

Daveecee — Sun, 27 Apr 2008 06:42:47 GMT

←Older revision		Revision as of 06:42, 27 April 2008
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	Most of the time, synesthesia is unidirectional (for example, most colored-hearing synesthetes do not hear sounds when they see colors). Also, even if patients have the same form of synesthesia, it is unlikely that their concurrents are the same, meaning: letters will not produce the same colors to different synesthetes.		Most of the time, synesthesia is unidirectional (for example, most colored-hearing synesthetes do not hear sounds when they see colors). Also, even if patients have the same form of synesthesia, it is unlikely that their concurrents are the same, meaning: letters will not produce the same colors to different synesthetes.
-
-	It is believed that synesthesia may have a genetic link, according to a twin study done by Hancock (2006). Hancock observed monozygotic twins, who both had color-number associations. The boys did not report seeing colors or even perceiving color experiences but, rather, had a simple association between numbers and colors, as if the numbers ''could be'' represented by colors. The genetic link was made possible by the discovery that the boys' mother also has a color-number association.
-
-	Synesthesia can also be a learned association. Witthoft and Winawer (2006) describe a case study in which their patient had a learned color-letter association as a byproduct of having colored refrigerator magnets as a child. Interestingly enough, this case also described the possibility that synesthetic color-letter associations can transfer between letters; their patient moved to Russia at the age of three, and her color-graphemic synesthesia transferred to Russian Cyrillik.

	== Color-graphemic ==		== Color-graphemic ==
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	In (time)→(location) synesthesia, the patient will arrange periods of time in a colored shape. For example, they may conceptualize the months of the year into a flat, horizontal loop surrounding them, and each month being a different color.		In (time)→(location) synesthesia, the patient will arrange periods of time in a colored shape. For example, they may conceptualize the months of the year into a flat, horizontal loop surrounding them, and each month being a different color.
		+
		+	== Causes ==
		+
		+	It is believed that synesthesia may have a genetic link, according to a twin study done by Hancock (2006). Hancock observed monozygotic twins, who both had color-number associations. The boys did not report seeing colors or even perceiving color experiences but, rather, had a simple association between numbers and colors, as if the numbers ''could be'' represented by colors. The genetic link was made possible by the discovery that the boys' mother also has a color-number association.
		+
		+	Synesthesia can also be a learned association. Witthoft and Winawer (2006) describe a case study in which their patient had a learned color-letter association as a byproduct of having colored refrigerator magnets as a child. Interestingly enough, this case also described the possibility that synesthetic color-letter associations can transfer between letters; their patient moved to Russia at the age of three, and her color-graphemic synesthesia transferred to Russian Cyrillik.

	== References ==		== References ==

Daveecee at 06:42, 27 April 2008

Daveecee — Sun, 27 Apr 2008 06:42:12 GMT

←Older revision		Revision as of 06:42, 27 April 2008
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	[[Category:Neuropsychological syndromes]]		[[Category:Neuropsychological syndromes]]
		+
		+	Synesthesia is a neurological syndromein which stimulation of one sensory modality automatically and uncontrollably triggers another sensory modality. The types of synesthesia discussed in class include:
		+
		+	#Color-graphemic synesthesia: written letters induce vivid color experiences
		+	#Colored-hearing: color experiences induced by spoken words
		+	#Numbers are projected into a spatial layout in front of the patient's chest, and are colored
		+	#Periods of time are conceptualized in a colored spatial layout
		+
		+	Synesthesia often begins in early childhood, but it can be brought about as a result of brain injury or sensory dedeafferentation.
		+
		+	Most of the time, synesthesia is unidirectional (for example, most colored-hearing synesthetes do not hear sounds when they see colors). Also, even if patients have the same form of synesthesia, it is unlikely that their concurrents are the same, meaning: letters will not produce the same colors to different synesthetes.
		+
		+	It is believed that synesthesia may have a genetic link, according to a twin study done by Hancock (2006). Hancock observed monozygotic twins, who both had color-number associations. The boys did not report seeing colors or even perceiving color experiences but, rather, had a simple association between numbers and colors, as if the numbers ''could be'' represented by colors. The genetic link was made possible by the discovery that the boys' mother also has a color-number association.
		+
		+	Synesthesia can also be a learned association. Witthoft and Winawer (2006) describe a case study in which their patient had a learned color-letter association as a byproduct of having colored refrigerator magnets as a child. Interestingly enough, this case also described the possibility that synesthetic color-letter associations can transfer between letters; their patient moved to Russia at the age of three, and her color-graphemic synesthesia transferred to Russian Cyrillik.
		+
		+	== Color-graphemic ==
		+
		+	[[image:synesthesia.png\|250px\|thumb\|How somebody with color-graphemic synesthesia may read words and numbers]]
		+
		+	In Color-graphemic synesthesia, written words, letters, and numbers induce vivid color experiences. The actual experience of color tends to vary from patient to patient. Patients may report any of the following:
		+
		+	#As seen in the image, perceiving letters and numbers as being colored rather than monochrome (black).
		+	#Seeing certain letters/words/numbers may cause the patient to see a screen of color "projected" onto their "mind's eye."
		+	#As above, but rather than being fully colored, the screen is a blurry and colored version of the letter they are seeing.
		+	#Patients may simply have an association between colors and letters/words/numbers without actually having a visual perception of color.
		+
		+	Sperling et. al (2006) found evidence that color-graphemic synesthesia is caused by an activation in the color areas ([[V4]]/V8) in the visual cortex as well as the inferior temporal lobe, another region known to be a cortical color processing system. A possible explanation for perceiving colors when seeing writing can be derived from activation of the superior temporal lobe and insula, which are hypothesized to mediate pathway convergence during the induction of a synesthetic-colour experience, leading to feedback-activation of visual areas responsible for color perception.
		+
		+	== Colored-hearing ==
		+
		+	In colored-hearing synesthesia, sounds produce an extrasensory experience of color. This is usually in response to tones or other aspects of sound. Usually, the sounds that produce colors in colored-hearing synesthetes are musical sounds, or environmental sounds (such as alarm clocks, or birds chirping). Like in color-graphemic synesthesia, activation in V4/V8 has been associated with the experience of color in response to music or environmental sounds.
		+
		+	== Number → Color & Shape ==
		+
		+	In (number)→(color/shape) synesthesia, the patient will project numbers in front of themselves in, for example, a coloured arc.
		+
		+	== Time → Location ==
		+
		+	In (time)→(location) synesthesia, the patient will arrange periods of time in a colored shape. For example, they may conceptualize the months of the year into a flat, horizontal loop surrounding them, and each month being a different color.
		+
		+	== References ==
		+
		+	Grossenbacher, P.G., & Lovelace, C.T. (2001). Mechanisms of synesthesia: Cognitive and physiological constraints. ''TRENDS in Cognitive Sciences, 5''(1), 36-41.
		+
		+	Hancock, P (2006). Monozygotic twins’ colour-number association: A case study. ''Cortex, 42'', 147-150.
		+
		+	Sperling, J. M., Prvulovic, D., Linden, D.E.J., Singer, W., & Stirn, A. (2006). Neuronal correlates of a colour-graphemic synaesthesia: A fMRI study. ''Cortex, 42'', 295-303.
		+
		+	Witthoft, N., & Winawer, J. (2006). Synesthetic colors determined by having colored refrigerator magnets in childhood. ''Cortex, 42'', 175-183.
		+
		+	== External Links ==

	[http://youtube.com/watch?v=DvwTSEwVBfc Tasting Colors]		[http://youtube.com/watch?v=DvwTSEwVBfc Tasting Colors]

JGasparri at 23:15, 24 April 2008

JGasparri — Thu, 24 Apr 2008 23:15:22 GMT

←Older revision		Revision as of 23:15, 24 April 2008
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	[[Category:Neuropsychological syndromes]]		[[Category:Neuropsychological syndromes]]
		+
		+	[http://youtube.com/watch?v=DvwTSEwVBfc Tasting Colors]

Admin at 20:59, 11 January 2008

Admin — Fri, 11 Jan 2008 20:59:47 GMT

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[[Category:Neuropsychological syndromes]]