AN ANALYSIS OF GABAERGIC AFFERENTS TO BASKET CELL-BODIES IN THE CATS CEREBELLUM

An antibody to glutamic acid decarboxylase (GAD) was used to identify GABAergic terminals around the somata of basket cells in the cat's cer ebellar cortex. Two sources for GAD immunoreactive terminals were iden tified based on size and cytological characteristics including the rec urrent collaterals derived from Purkinje cells and the axons of stella te cells. The majority of the unlabeled terminals likely arise from pa rallel fibers. The present analysis indicates that GAD-positive termin als form 13% of the synaptic contacts on basket cells. The remaining 8 7% are unlabeled. Thus, GAD-positive terminals represent a small propo rtion of the synaptic input to basket cell bodies as compared to affer ent endings that likely mediate excitation.