Abstract
Perceptual decision making is regarded as a process to integrate sensory signals toward appropriate action. Perceptual decision is made more quickly and more precisely with increasing the strength of signals and this tendency is reflected by the dorsal lateral prefrontal and intraparietal areas (Kim and Shadlen, 1999). At the same time, perceptual decision is also made by statistical knowledge of past experience (Carpenter and Williams, 1995; Shadlen, Britten et al., 1996; Rome, Brody et al., 1999; Gold and Shadlen, 2007). Does signal from statistical knowledge determine perceptual decision making similarly to current sensory signals? If so, statistical knowledge based on stronger signal should more greatly influence perceptual decision making. Last year, we showed that a past-experienced very weak signal more greatly influences decision making than stronger signals (Nishina, Kim, Watanabe, VSS, 2010). Here, we conducted fMRI experiments to examine the underlying mechanism for this puzzling bahavioral finding. Using a multivoxel pattern analysis (MVPA) originally developed by Kamitani and Tong (2005), we found that the behavioral results were significantly highly correlated to the decoded performance based on fMRI signals in ventral prefrontal areas but not to that in dorsal lateral prefrontal or intraparietal areas. These results indicate that ventral lateral prefrontal areas reflect an influence of past experiences of weak signals on decision masking.
NIH R01 (EY015980, EY019466, AG031941, MH091801).