Role of the basal ganglia in manifestation of rhythmical jaw movement in rats

Abstract

Microinjection of picrotoxin (PTX), a selective GABA antagonist, into the rostral part of the head of the caudate-putamen complex (CPC) produced rhythmical potentials of 3-11 Hz there that lasted for about 5-15 s in the rat. Rhythmical jaw movements (RJM) were observed to be associated with these rhythmical potentials. Since the potentials were still observed even after the CPC had been isolated, they were thought to be generated intrinsically by the CPC itself. Increased and grouped neuronal discharges of the CPC were recorded in association with the rhythmical potentials. Periodic or prolonged inhibition of neurons of the pars reticulata of the substantia nigra were also recorded in association with the rhythmical potentials in the CPC. We therefore propose that the basal ganglia are involved directly in the manifestation of RJM in the rat.