[Ipsilateral motor responses of the facial muscles to intracortical microstimulation in the white mouse].

Motor responses (MRs) of facial muscles to intracortical microstimulation (ICMS) of lightly anaesthetized outbred white mice were observed visually and recorded by means of photodiodes. ICMS rostral to bregma, within cortical band along sagittal suture (area 6) evoked mostly ipsilateral MRs of vibrissae and upper lip, more often from the left hemisphere. MRs of the lower jaw, tongue and larynx were induced by ICMS in symmetrical zones of both hemispheres. The lowest thresholds of ICMS, 2-20 mcA, were revealed at the depth from 0.8-1.1 mm up to 1.3-1.7 mm, i. e. in layers III and V. Short-latency (from 10 to 25 ms) MRs of the vibrissae, lip and jaw were evoked by high-frequency volleys of 2 to 5 pulses. The participation of some oligosynaptic components in cortico-facial descending projections in the white mouse is supposed.