BILATERAL LESIONS IN THE CEREBELLAR INTERPOSITUS-DENTATE REGION IMPAIR TASTE-AVERSION LEARNING IN RATS

Taste Aversion Learning (TAL) has been induced through two different b ehavioral procedures: a shea-term o concurrent (two-daily flavors) and a long-term (one-daily flavor) procedure. For the first, two gustator y/olfactory stimuli are presented separately but at the same time on a daily basis. One of the flavors is paired with simultaneous intragast ric administration of hypertonic NaCl and the other is paired with phy siological saline. In the long-term procedure, the two stimuli are pre sented on alternate days, one of them followed by intragastric injecti on of the aversive stimulus, and the other by saline. The subjects for both types of tests were animals that had been lesioned in the interp ositus-dentate region of the cerebellum. The experiments show that the lesions disrupt short-term TAL, but have no effect on long-term TAL. The results are discussed in terms of the role of the cerebellum in re lation to TAL and the different anatomical substrates of both learning modalities. (C) 1998 Elsevier Science Inc.