Functional and Structural mapping of the somatosensory homunculus in the newborn brain

Abstract

The human body’s representation within the primary somatosensory cortex of the brain is highly organized, and can be topographically mapped as a “homunculus”. Specific areas of the body are represented in particular regions (the upper body infero-laterally, and the lower body supero-medially) and others are seemingly over-represented due to their rich neural innervation in comparison to their actual physical size (such as the lips and tongue). How and when this representation emerges in early human brain development has not been explored, although animal models suggest both activity-dependent and genetic factors are involved during a critical period equivalent to the second and third trimester [1].