Spared and impaired aspects of motivated cognitive control in schizophrenia

The ability to upregulate cognitive control in motivationally salient situations was examined in individuals with schizophrenia (patients) and healthy controls. Fifty-four patients and 39 healthy controls were recruited. A computerized monetary response conflict task required participants to identity a picture, over which was printed a matching (congruent), neutral, or incongruent word. This baseline condition was followed by an incentive condition, in which participants were given the opportunity to win money on reward-cued trials. These reward-cued trials were interleaved with nonreward cued trials. Reaction times (RT) were examined for both incentive context effects (difference in RT between baseline and nonreward cue trials in the incentive condition) and incentive cue effects (difference in RT between nonreward and reward cue trials in the incentive condition). Compared with baseline, controls showed a speeding of responses during both the nonreward (incentive context effect) and reward cued (incentive cue effect) trials during the incentive condition, but with a larger incentive context than incentive cue effect, suggesting a reliance on proactive control strategies. Although patients also showed a speeding of responses to both nonreward and reward cued trials, they showed a significantly smaller incentive context effect than controls, suggesting a reduction in the use of proactive control and a greater reliance on the use of "just-in-time," reactive control strategies. These results are discussed in light of the relationship between motivation and cognitive impairments in schizophrenia, and the potential role of impairments in prefrontally mediated active maintenance mechanisms.