Deficits in reward sensitivity in a neurodevelopmental rat model of schizophrenia

Neonatal ventral hippocampal lesions in rats have been shown to result in behavioral abnormalities at adulthood thought to simulate some aspects of positive and cognitive deficits classically observed in schizophrenic patients. We investigated whether such lesions can also induce deficits in reward sensitivity that are related to the negative symptoms of psychotic disorders. To investigate the effects of neonatal and adult lesions of the ventral hippocampus on reward-related behaviors we used the conditioned place preference (CPP) test and the saccharin consumption model. In contrast to adult-lesioned animals, neonatally lesioned rats exhibited a deficit in amphetamine-induced CPP and a significant reduction in saccharin preference. These deficits are unlikely due to lesion-induced motor impairments as both neonatal- and adult-lesioned rats exhibited a similar hyperlocomotor response to amphetamine. Taken together, these results show that neonatal ventral hippocampal lesions induce a reduction in reward-seeking behaviors in adulthood that mimic some aspects of the negative symptoms (anhedonia) in psychotic patients.