EFFECTS OF REGIONAL GABAERGIC BLOCKADE OF THE STRIATUM ON MEMORY CONSOLIDATION

The prediction was made that blocking the action of gamma-aminobutyric acid (GABA) in different regions of the striatum, through local injec tion of picrotoxin, would produce differential amnestic effects. Rats were trained in an inhibitory avoidance task, and a retention test was carried out 24 h later. Posttraining injection of picrotoxin (1 mu g/ 1 mu l) into posteroventral and lateral regions produced strong amnesi a; an intermediate degree of impairment was found when delivered at do rsomedial regions; and no retention deficit was found when given to th e ventromedial aspect of the anterior striatum. In sum, the retention impairments were consistently higher in posterior and lateral striatal regions than in the anterior and medial regions. The present findings support the concept that striatal GABAergic activity is involved in m emory functions and also provide further evidence of neurochemical het erogeneity within the striatum regarding memory consolidation. (C) 199 6 Academic Press, Inc.