Cortical areas of bilateral representation of hand movements | Aree corticali di rappresentazione bilaterale dei movimenti della mano

PET and fMRI studies have disclosed areas of activation in the ipsilateral primary sensorimotor cortex, which appears to be spatially much more extensive in the dominant hemisphere during sequential finger movements. This study directly investigated the presence and spatial distribution of controlateral, bilateral and ipsilateral cortical motor representations in both hemispheres using echo planar fMRI. FMRI disclosed different populations of neurons with specific functional characteristics in an anatomically defined area. There was no purely ipsilateral representation of movement; the ipsilateral component of cortical activation seems to reflect a population of neurons activated during movement of both right and left hands with greater extension in the dominant hemisphere. This bilateral population is presumably involved in movement planning. A second neuron population, activated only during the controlateral movement, was found in both hemispheres in the posterior portion of the precentral gyrus, probably corresponding to the primary motor area