The role of the medial prefrontal cortex in attention: Altering predictability of task difficulty

Abstract

Rats were trained on a signal detection task in which a light (200 or 500 msec) appeared randomly over one of three levers. The rat was required to press the illuminated lever. There were two versions of the task: a light detection-random (LDR) and a light detection-block (LDB) task that differed only in the predictability of the difficulty level of the upcoming stimuli (LDR = unpredictable; LDB = predictable). Scopolamine infusions into the anterior cingulate and the prelimbic cortex significantly impaired choice accuracy in the LDR, but not in the LDB task. However, saline infusions into the prelimbic cortex also decreased choice accuracy, suggesting that the prelimbic cortex is particularly sensitive to disruption under conditions of high attentional demand. Overall, the results indicate that the prefrontal cortex is involved in mediating performance on tasks in which the difficulty level is unpredictable, thus requiring more focused attention throughout the task.