[Effect of stimulation of rostral portions of the midbrain reticular formation on the cat motor cortex].

Evoked potentials and responses of 139 neurones in the sensorimotor cortex (the lateral third of the posterior sigmoid gyrus) to electrical stimulation of the dorsolateral (DL) and the ventromedial (VM) areas of the mesencephalic reticular formation (MRF) were investigated in cats in acute and chronic experiments. Latencies of the cortical unit responses (in the form of single and multiple discharges) to MRF stimulation varied from 4 to 36 msec for VM (maxima of distribution: 4--10 and 18--24 msec); those for DL were from 4 to 26 msec (maxima of distribution: 4--6 and 14--16 msec). Responses to both DL and VM stimulation were observed in 29 neurones. As for MRF, its effects (mono-and polyvalent) were found in cortical neurones responding to limb electrocutaneous stimulation as well. At 7--10 days after coagulation of the ipsilateral connection between MRF and the pons, persistence of the cortical response main components was recorded, the long-latency part being slightly reduced.