Functional mapping of the motor cortex of the white mouse by a microstimulation method.

Studies on 33 anesthetized white mice were used to determine the motor representation of facial muscles and limb muscles by an intracortical microstimulation method. Microstimulation produced predominantly ipsilateral movement responses of facial muscles and contralateral responses in fore- and hindlimb muscles. Low-threshold stimulation in the left and right hemispheres showed a clear asymmetry of the motor representation of the facial muscles. Movement responses of the hindlimbs were obtained on microstimulation of the frontal regions of the neocortex, demonstrating the existence of multiple motor representations of muscles in the neocortex.