Glucocorticoids in the dorsomedial striatum modulate the consolidation of spatial but not procedural memory.

Glucocorticoid hormones are known to influence widely interconnected brain networks, thereby enhancing the consolidation of memory of several types of training experiences. In this network, the dorsal striatum plays an important role in transforming goal-directed behavior into habitual behavior. Many studies have shown that the dorsolateral striatum (DLS) enables the formation of stimulus-response associations that are needed for procedural learning. In contrast, the dorsomedial striatum (DMS) is predominantly involved in influencing goal-directed behaviors via interactions with the dorsal hippocampus and medial prefrontal cortex. To date, most studies that have supported a functional dissociation of the dorsal striatum in memory have focused on the behavioral deficits produced by lesions or temporary inactivation of different striatal regions. Few studies have investigated the effect of pharmacological activation of the DMS in modulating memory of distinct kinds of spatial navigation. Therefore, in the present study corticosterone (CORT) was administered into the DMS immediately after training on either a place or cue water-maze task to investigate possible effects on the consolidation of spatial and procedural memory. Our findings indicate that CORT (5, 10 and 20 ng) enhanced 24-h retention of place training, without affecting retention of cue training. However, CORT administration after place and cue training did not shift the selection from a procedural to a spatial navigation strategy in a place-cue competition test. These findings support the functional heterogeneity of the dorsal striatum and suggest that the DMS can modulate the consolidation of allocentric spatial information via glucocorticoid action.