Secondary somatosensory cortex



Brodmann area 40, or BA40, is part of the parietal cortex in the human brain. BA40 is in the area of the supramarginal gyrus, which lies at the posterior end of the lateral fissure, in the inferior lateral part of the parietal lobe.

This area is also known as supramarginal area 40 (H). It is bounded approximately by the intraparietal sulcus, the inferior postcentral sulcus, the posterior subcentral sulcus and the lateral sulcus. Cytoarchitecturally it is bounded caudally by the angular area 39 (H), rostrally and dorsally by the caudal postcentral area 2, and ventrally by the subcentral area 43 and the superior temporal area 22 (Brodmann-1909).

Anatomy
This region, forming the superior bank of the sylvian fissure, as studied in the cat, contains the secondary somatosensory representation, 'S-II', and a second somatotopic representation (parietal ventral, or PV). Anatomically, primate S-II receives inputs from area 3 and area 1, and projects to PV and area 7. PV has projections to area 5 and premotor areas.

Function
Single cell recording in primates show neurons with larger receptive fields than primary somatosensory cortex, responding to bilateral tactile stimuli, and showing attentional modulation.

In humans, PO is activated during somatosensory stimulation, texture discrimination tasks, and in motor tasks involving sensory feedback. It is also involved in tactile learning and memory, and may also perform co-ordinate transformations from the somatotopic to other spatial frames.