Nicotine improves Morris water task performance in rats given medial frontal cortex lesions

The object of this study was to investigate whether nicotine would improve cognitive impairments produced by medial frontal cortex lesions in rats behaviorally tested on the Morris water task (MWT). Rats were assigned to either a lesion or sham group. In the lesion group, animals were given vehicle (peanut oil) treatment or treatment with nicotine for 11 consecutive days before, after, or before and after a medial frontal cortex lesion. Additionally, a sham group was included that was given vehicle both before and after the lesion. Results showed that lesioned rats receiving pre- or post-operative nicotine treatment demonstrated improved Morris task acquisition performance relative to the lesioned group given the vehicle, although a deficit was shown relative to shams. On the probe trial, rats that received a pre- and post-treatment of nicotine demonstrated performance equivalent to shams and had significantly better performance than rats that received nicotine treatment before the lesion and lesioned animals treated with the vehicle. These results demonstrate that nicotine has therapeutic effects in rats that have received cortical injury.