Notes on the Olivocerebellar Connections *

In a previous communication' evidence was adduced to indicate that the dorsal accessory olives of the medulla are connected with the dorsal part of the vermis (lingula, lobus centralis, culmen and declive) and that the ventromedian accessory olives and the ventral limbs of the inferior olives are connected with the ventral part of the vermis (folium, tuber, pyramis, uvula and nodulus). Holmes and Stewart2 and Brouwer3 previously had stated that there is a definite regional relationship between the different portions of the inferior olives and the different areas of the cortex of the cerebellum; that the dorsal olivary loops are connected with the dorsal cerebellar cortex, the ventral with the ventral part, the medial with the medial, and the lateral with the lateral part of the cortex. Brouwer also quoted Bruns to the effect that the inferior olives send fibers to the uncrossed cerebellar cortex by way of the homolateral restiform body. These fibers were said to take origin from the dorsal portion of the olive. These views on the olivocerebellar relationships are contradicted by the findings in the case reported by Spiller4, in which were present atrophy and sclerosis involving the vermis, lateral cerebellar lobes and inferior olives, but no changes in the accessory olives. Further doubt on the olivocerebellar connections was cast in a recent report by Pines and Surabaschwili5, who described an almost complete absence of the ventral part of the vermis in an individual who had, nevertheless, intact dorsal and median accessory olives. Recently, the present writers had the opportunity to study the relationships between the olivary bodies and the various parts of the cerebellum in three cases which are presented in this communication. This is done in the hope that some light will be thrown on what is still a controversial question.