Quantitative prediction of perceptual decisions during near-threshold fear detection

A fundamental goal of cognitive neuroscience is to explain how “mental decisions” originate from basic neural mechanisms. In a recent study (PNAS, 2005), we investigated the neural correlates of perceptual decisions in the context of emotional perception. To probe this question, we investigated how fluctuations in fMRI signals were correlated with behavioral choice during a near-threshold fear detection task. fMRI signals predicted behavioral choice independently of stimulus properties and task accuracy in a network of brain regions linked to emotional processing: posterior cingulate cortex, medial prefrontal cortex, right inferior frontal gyrus, and left insula. We quantified the link between fMRI signals and behavioral choice in a whole-brain analysis by determining “choice probabilities” via signal detection theory methods. Our results demonstrate that voxel-wise fMRI signals can reliably predict behavioral choice in a quantitative fashion (choice probabilities ranged from 0.63-0.78) at levels comparable to neuronal data. We suggest that the conscious decision that a fearful face has been seen is represented across a network of interconnected brain regions that prepare the organism to appropriately handle emotionally challenging stimuli and that regulate the associated emotional response.