Cortical homunculus

Nerve fibres—conducting somatosensory information from all over the body—terminate in various areas of the parietal lobe in the cerebral cortex, forming a representational map of the body.

Findings from the 2010s and early 2020s began to call for a revision of the traditional "homunculus" model and a new interpretation of the internal body map (likely less simplistic and graphic), and research is ongoing in this field.

The primary motor cortex is located in the precentral gyrus, and handles signals coming from the premotor area of the frontal lobes.

[6][7][8] Wilder Penfield and his co-investigators Edwin Boldrey and Theodore Rasmussen are considered to be the originators of the sensory and motor homunculi.

[8][9] More recent studies have improved this understanding of somatotopic arrangement using techniques such as functional magnetic resonance imaging (fMRI).

Rather than the sharp delineation between different body areas shown in the drawings, there is actually significant overlap between neighboring regions.

This finding suggests that the motor cortex functions in terms of overall movements as coordinated groups of individual motions.