The term supplementary motor area proper refers to the more posterior of two parts of mesial premotor cortex in the macaque and the human. It is defined on the basis of internal structure, neurochemistry, connections and function ( Matelli-2004 ). In both species it is located on the mesial surface rostrally in the precentral gyrus. In the human it extends to the VCA line caudally in the superior frontal gyrus; in the macaque it occupies more of the precentral gyrus and less of the superior frontal gyrus than in the human. It is associated with area 6a alpha of Vogts. In the macaque it is also known as area F3. Its major input is from the adjacent dorsal part of the anterior cingulate gyrus, and the posterior mesial part of the superior parietal lobule (area PECg). It is more activated with the performance of simple motor tasks than in motor tasks requiring selection between actions. Electrical stimulation elicits multi-joint movements of the proximal, postural musculature more than of distal musculature. Unlike primary motor cortex, the parts of supplementary motor area proper mediating movements of different body parts overlap, but, as in primary motor cortex, there exists a rostrocaudal face-arm-leg gradient. It is proposed to control motor function globally by mediating postural adjustments appropriate to simple actions and in executing automatic motor sequences. In the human, the supplementary motor area proper is subdivided into to two areas: a rostral area SMAr and a more caudal area SMAc. The more anterior part of mesial premotor cortex itself is the presupplementary motor area.