The schizophrenia risk gene Map2k7 regulates responding in a novel contingency-shifting rodent touchscreen gambling task

Abstract

In schizophrenia, subjects show reduced ability to evaluate and update risk/reward contingencies, showing correspondingly suboptimal performance in the Iowa gambling task. JNK signalling gene variants are associated with schizophrenia risk, and JNK modulates aspects of cognition. We therefore studied the performance of mice hemizygous for genetic deletion of the JNK activator MKK7 (Map2k7+/− mice) in a touchscreen version of the Iowa gambling task, additionally incorporating a novel contingency-switching stage. Map2k7+/− mice performed slightly better than wild-type (WT) littermates in acquisition and performance of the task. Although Map2k7+/− mice adapted well to subtle changes in risk/ reward contingencies, they were profoundly impaired when the positions of ‘best’ and ‘worst’ choice selections were switched, and still avoided the previous ‘worst’ choice location weeks after the switch. This demonstrates a precise role for MKK7–JNK signalling in flexibility of risk/reward assessment and suggests that genetic variants affecting this molecular pathway may underlie impairment in this cognitive domain in schizophrenia. Importantly, this new contingency shift adaptation of the rodent touchscreen gambling task has translational utility for characterising these cognitive subprocesses in models of neuropsychiatric disorders.