Conditional engagement of medial frontal cortex during responding under uncertain reinforcement in rats: a paradigm for subjective behavior.

Rats were studied for their performance on DRL 10 s and 5 s with 50% probability of reinforcement, before and after medial frontal cortical lesions. A sequential analysis of interresponse times (IRTs) was carried out. It suggested 1. that the medial frontal cortex mediates subjective risk of response choice in rats and 2. that the tolerated risk levels in human decision-making may have a biological basis.