Subchronic phencyclidine treatment impairs performance of C57BL/6 mice in the attentional set-shifting task

Schizophrenic patients show deficits in their ability to shift attention to new stimuli during attentional set-shifting tasks. An equivalent task has been developed in rodents. This task was used to assess effects of phencyclidine (PCP), a drug widely used to model schizophrenia, in mice. Mice were administered PCP (0.63 or 1.3 mg/kg) daily, beginning 5 days prior to training and continuing throughout the test period. Mice were trained to discriminate stimuli to find a food reward in a series of discriminations. PCP increased the number of trials required to reach the criterion during simple and reversal discriminations, but not when the discriminations were repeated with a new set of stimuli (i.e. during the intradimensional shift and its reversal), suggesting an interaction between PCP effects and novelty. The 1.3 mg/kg of PCP also impaired performance of mice during the extradimensional shift. Similar results have been reported in schizophrenic patients. Although, in control mice, performance of the extradimensional shift was not impaired relative to the intradimensional shift, suggesting that the mouse may not be a suitable species for assessment in this model, specific discriminations within this task were sensitive to impairment by PCP, implying, therefore, that it may have some utility in modelling discrete aspects of schizophrenia in humans.