PT - JOURNAL ARTICLE AU - Jeffrey C. Erlich AU - Bingni W. Brunton AU - Chunyu A. Duan AU - Timothy D. Hanks AU - Carlos D. Brody TI - Distinct effects of prefrontal and parietal cortex inactivations on an accumulation of evidence task in the rat AID - 10.1101/011031 DP - 2015 Jan 01 TA - bioRxiv PG - 011031 4099 - http://biorxiv.org/content/early/2015/03/21/011031.short 4100 - http://biorxiv.org/content/early/2015/03/21/011031.full AB - Numerous brain regions have been shown to have neural correlates of gradually accumulating evidence for decision-making, but the causal roles of these regions in decisions driven by accumulation of evidence have yet to be determined. Here, in rats performing an auditory evidence accumulation task, we inactivated the frontal orienting fields (FOF) and posterior parietal cortex (PPC), two rat cortical regions that have neural correlates of accumulating evidence and that have been proposed as central to decision-making. We used a detailed model of the decision process to analyze the effect of inactivations. Inactivation of the FOF induced substantial performance impairments that were quantitatively best described as an impairment in the output pathway of an evidence accumulator with a long integration time constant (>240ms). In contrast, we found a minimal role for PPC in decisions guided by accumulating auditory evidence, even while finding a strong role for PPC in internally-guided decisions.