Glucocorticoid hormones enhance memory consolidation of hippocampus-dependent spatial/contextual learning, but little is known about their possible influence on the consolidation of procedural/implicit memory. Therefore, in this study we examined the effect of corticosterone (2, 5, or 10 ng) infused into the dorsal striatum of male Wistar rats immediately after training on either a cued or spatial version of the water maze. We found that corticosterone dosedependently enhanced 48-h retention of the cued training without affecting the retention of the spatial training. These findings indicate that corticosterone acts within the dorsal striatum to enhance memory consolidation of procedural/ implicit training.It is well established that adrenocortical hormones, released during stressful stimulation, enhance the consolidation of memory of emotionally arousing experiences (de Kloet et al. 1999;Roozendaal 2000;Joëls et al. 2006;Sandi and Pinelo-Nava 2007;Roozendaal et al. 2008). Most studies have examined glucocorticoid effects on memory consolidation in relation to hippocampal function in experiments using tasks that have a strong spatial and/or contextual component, including water-maze spatial training, contextual fear conditioning, and inhibitory avoidance training (Roozendaal and McGaugh 1996;Pugh et al. 1997;Roozendaal et al. 1999a). Similarly, studies in human subjects emphasized an involvement of cortisol in modulating the consolidation of declarative memory (Buchanan and Lovallo 2001;Abercrombie et al. 2003;Andreano and Cahill 2006;Kuhlmann and Wolf 2006). However, growing evidence indicates that glucocorticoid hormones also enhance memory consolidation of training that does not appear to depend crucially on an intact hippocampus. We recently reported that glucocorticoids enhance the consolidation of memory of conditioned taste aversion training when infused into the insular cortex or basolateral complex of the amygdala, but not into the hippocampus (Miranda et al. 2008). Other studies indicated that glucocorticoids administered systemically enhance memory consolidation of hippocampus-independent auditory cue fear conditioning (Zorawski and Killcross 2002;Hui et al. 2004) and object recognition (Okuda et al. 2004;Roozendaal et al. 2006). Surprisingly little is known regarding a possible influence of glucocorticoids on the consolidation of memory of procedural or nondeclarative training. Although several studies have now reported that glucocorticoid administration, stress exposure, or an anxious emotional state, either shortly before training or before retention testing, shifts the relative use of spatial/declarative (''cognitive'') versus procedural/implicit (''habit'') response strategies (Kim et al. 2001;Schwabe et al. 2008Schwabe et al. , 2009Packard 2009a), these studies did not investigate whether glucocorticoids affect the consolidation of procedural memory. Moreover, findings suggest that such a bias in learning strategy is predominantly attributable to a stress-induced alteration of hippocampal functi...