DIFFERENTIAL-EFFECTS OF UNILATERAL LIDOCAINE INFUSION INTO THE GLOBUS-PALLIDUS ON CONSOLIDATION AND PERFORMANCE OF INHIBITORY AVOIDANCE

The striatum is involved in memory consolidation; also involved in thi s process is one of its two major efferent targets, namely, the substa ntia nigra. It is not clear, however, if the other target, the globus pallidus, participates in storage and/or performance of learned inform ation. To examine this problem, male Wistar rats were trained in an in hibitory avoidance task and tested for retention 24 h afterward. Indep endent groups were infused, unilaterally, with 2% lidocaine in the pal lidus either 2 min after training or 2 min before testing. No disturba nces of memory were detected with posttraining infusion, but a signifi cant deficit in retention was observed as a consequence of pretest inf usion. Infusion of isotonic saline into the globus pallidus, or of lid ocaine before testing into the parietal cortex, after training into th e ventral thalamic nucleus, and both before training and testing into this thalamic nucleus were without effect. Taken together, the data in dicate that unilateral inactivation of the GP interferes with retrieva l of information derived from inhibitory avoidance training, but not w ith the early stages of memory consolidation of this task, and other w ork indicates that the pallidus may be involved in a late phase of thi s process. (C) 1998 Academic Press.