Tactile extinction following unilateral lesions in the rat anteromedial cortex: effects of a contralateral cue.

Following unilateral lesions of the anteromedial cortex (AMC) or the caudal forelimb representation (CFL), rats prefer to remove an adhesive patch placed on the forelimb ipsilateral to the lesion before removing a simultaneously applied contralateral patch (i.e., ipsilateral asymmetry). The present experiment was designed to investigate the possibility that attention has some role in these asymmetries. Specifically, the researchers investigated whether a contralateral tactile cue presented before the simultaneous presentation of bilateral tactile stimuli would neutralize the ipsilateral asymmetry. In rats with AMC lesions, the contralateral cue neutralized the ipsilateral bias, whereas the cue had no effect on rats with CFL lesions. These data suggest that the ipsilateral bias observed in AMC-damaged rats may reflect an impairment in attention.