The anterior claustrum and spatial reversal learning in rats

The claustrum is a small structure of poorly understood function situated subcortically in the basal forebrain. The fact that it is extensively and reciprocally connected with the cerebral cortex has led to suggestions that it is involved in coordination of cortical activity. In this study, we created excitotoxic lesions to the anterior claustrum of rats and tested performance on three tasks that involve neural processing in one or more frontal and limbic cortical structures. We tested reversal learning and spatial working memory in a water maze and tested latent inhibition using conditioned taste aversion. Lesioned rats were not impaired at acquiring the initial location of the platform in a water maze, but were impaired at acquiring a switched location in the reversal phase. The lesioned rats also exhibited an increased rate of perseverance errors compared to control rats during reversal. Lesioned rats were not impaired in the working memory task or latent inhibition. These results indicate that cell loss in the claustrum may lead to deficits in behavioral flexibility, and are consistent with theories of claustral function that suggest it may help coordinate information necessary for at least some cortical-dependent tasks.