Effect of orofacial motor cortex stimulation on neuronal activity in the red nucleus.

We studied modulation of the activities of the red nucleus (RN) neurons under to electrical stimulation of the orofacial motor cortex (OfM) in urethane-anesthetized rats. Of 57 neurons studied, 30 (53%) neurons modulated the firing patterns. The firing patterns of the RN neurons were classified into four types: an excitation (E) type (n=4), a long inhibition (LI) type (n=4), a short inhibition (SI) type (n=22), and a no-effect type (n=27). These modulated neurons were intermingled in the dorso-ventral part of the RN. Our results suggest that the RN neurons receive excitatory or inhibitory inputs from the OfM.