Development and Maintenance of Somatotopic Maps of the Skin: A Mosaic Hypothesis Based on Peripheral and Central Contiguities (Part 2 of 2)

Abstract

The somatotopic mapping of tactile information from the skin onto structures in the brain is ubiquitous in the somatosensory system of mammals. This paper reviews evidence which suggests that the somatotopic map in the S-I cortex of the rat is not a single topographic entity but, instead, is a mosaic. This mosaic is comprised of subunits that process information from inputs which, by nature of their peripheral grouping and associated distribution to unified receptor surfaces, provide spatially and temporally contiguous signals. These subunits are developed and subsequently maintained in a piecemeal fashion within the integrated somatotopic map of the body. The relative size of the subunits is alterable by different mechanisms in newborn and adult animals.