[Harmaline tremor: topography of activity in the cerebellar cortex in rats]

In the Rat under tremorogenic doses of harmaline, Purkinje cells of the vermis of the cerebellar cortex display a regular complex spike activity at 6 to 11 Hz ("harmaline-rhythm"). With increased laterality of the recorded units, the rhythm loses its regularity and then disappears. The intermediate regions thus contain less harmaline sensitive units, while lateral regions and those corresponding to the vestibulo-oculomotor system did not present any such units. These results indicate that the parts of the olivo-cerebellar system activated by harmaline in the Rat are homologous to those already known in the Cat, and do not coincide with those of the inferior olive where a serotonergic innervation has been described.