The influence of risky and conservative mental sets on cerebral activations of cognitive control.

Mental set is known to influence cognitive functioning. Risk-seeking and risk-aversive mental sets alter cerebral responses to conflicting events. Here, building on our previous imaging work of the stop signal task, we introduced a "reward uncertainty" condition to elicit changes in participants' mental sets and examined how individual differences altered the neural responses to salient events. Approximately half of 27 adult participants - the Conservatives - became more risk-aversive in the "reward" as compared to the "standard" condition, by slowing down in go reaction time. We hypothesized that stop errors were more salient for these participants, as compared to the other subjects - the Riskys - who speeded up in go reaction time in the reward as compared to standard condition. With statistical parametric mapping, we showed greater activation of the retrosplenial cortex, somatosensory cortex, pre-supplementary motor area, and thalamus during stop error, in contrast to stop success trials, in the Conservatives as compared to Riskys. These results provided evidence that mental set influences cerebral activations during stop signal performance and extended the potential utility of the stop signal task in elucidating the contextual effects on cognitive control.