Rats with bilateral lesions of the medial frontal cortex were tested in a T-maze for the ability to learn a position habit and to make four reversals of it. Rats with medial frontal cortical lesions showed deficits in reversal learning. In addition, they were found to be hyperactive in an open field. Treatment with the dihydropyridine calcium channel antagonist, nimodipine, did not reduce these behavioral deficits.