Supramarginal gyrus

Important functions

The supramarginal gyrus is part of the somatosensory association cortex, which interprets tactile sensory data and is involved in perception of space and limbs location. It is also involved in identifying postures and gestures of other people and is thus a part of the mirror neuron system.

The right-hemisphere supramarginal gyrus appears to play a central role in controlling empathy towards other people. When this structure is not working properly or when individuals have to make very quick judgements, empathy becomes severely limited. Research has shown that disrupting the neurons in the right supramarginal gyrus causes humans to project emotions on others, inhibiting the ability to be empathetic. In addition, this disruption also causes people to be more egocentric, mainly because they are not able to perceive the emotions of those around them. Both the left and right supramarginal gyri of healthy, right-handed individuals are shown to be active when making phonological word choices. Individuals who had lesions to the left hemisphere had more difficulty than those with lesions to the right hemisphere, reinforcing the dominance of the left hemisphere in language.

Relationships to surrounding structures

The supramarginal gyrus is located just anterior to the angular gyrus allowing these two structures (which comprise the inferior parietal lobule) to form a multimodal complex that receives somatosensory, visual, and auditory inputs from the brain. Although the supramarginal gyrus is not considered a major portion of the language circuit, it still works with the angular gyrus to attempt to link words with meanings. It is also bound caudally by the lateral sulcus, one of the most prominent structures found in the brain.

Additional images

File:Supramarginal gyrus animation small.gif|Position of supramarginal gyrus (shown in red).

References

References

1. Gazzaniga, M.S., Ivry, R.B. and Mangun, G.R., ''Cognitive Neuroscience, the Biology of the Mind'', third edition, 2009, W.W. Norton, publishers. pgs. 395–401
2. Carlson, N. R. (2012). Physiology of Behavior 11th Edition. Pearson. pp. 83; 268; 273-275
3. (May 1994). "The nature of tactile agnosia: a case study". Neuropsychologia.
4. "I'm OK, you're not OK: Right supramarginal gyrus plays an important role in empathy".
5. [[Tania Singer. Singer, Tania]]. "ARE YOU EGOCENTRIC? CHECK YOUR RIGHT SUPRAMARGINAL GYRUS." Degreed, 28 May 2014. Web. 3 July 2014.
6. (2010-09-21). "Phonological decisions require both the left and right supramarginal gyri". Proceedings of the National Academy of Sciences.
7. "THE BRAIN FROM TOP TO BOTTOM".