Contributions of striatal subregions to place and response learning

Abstract

The involvement of different subregions of the striatum in place and response learning was examined using a T-maze. Rats were given NMDA lesions of the dorsolateral striatum (DLS), anterior dorsomedial striatum (ADMS), posterior dorsomedial striatum (PDMS), or sham surgery. They were then trained to retrieve food from the west arm of the maze, starting from the south arm, by turning left at the choice point. After 7 d of training, with four trials a day, a probe test was given in which the starting arm is inserted as the north arm, at the opposite side of the maze. A left turn would indicate a "response" strategy; a right turn, a "place" strategy. The rats were then trained for 7 more days, followed by a second probe test. Unlike rats in the other groups, most of the rats in the PDMS group turned left, using the response strategy on both probe tests. These results suggest that the PDMS plays a role in spatially guided behavior.

Figure 1

The extent of damage caused by NMDA lesions. SHAM, sham operated controls; ADMS, anterior dorsomedial striatum; PDMS, posterior dorsomedial striatum; DLS, dorsolateral striatum. From top to bottom the distances from bregma in mm are: DLS and ADMS, 1.6, 1, 0.48, -0.26; PDMS, 0.2, -0.26, -0.3, -0.8.

Figure 2

Performance across 14 d of acquisition training. Abbreviations as in Figure 1.

Figure 3

The results from both probe tests. Abbreviations as in Figure 1. The numbers in the parentheses show how many rats from each lesion group made that particular choice (place or response).