[Harmaline tremor: activity of the interposito-rubral system and of the bulbo-ponto-reticular formation].

The effects of tremogenic doses of harmaline have been studied by extracellular unit recordings and 14C 2-deoxyglucose marking in two groups of cats. Harmaline sensitive neurons were found in the lateral reticular nucleus and the nucleus reticularis tegmenti pontis. The nucleus interpositus as well as the red nucleus were also found to be discharging at the tremor frequency, indicating that the cerebello-interposito-rubral system participates in harmaline tremor. In cats with unilateral sections of the inferior cerebellar peduncle, 14C 2-deoxyglucose marking demonstrated that the increased activity previously observed in those structures was a consequence of harmaline acting on the inferior olive.