title: Content-specific evidence accumulation in inferior temporal cortex during perceptual decision-making.
abstract: During a perceptual decision, neuronal activity can change as a function of time-integrated evidence. Such neurons may serve as decision variables, signaling a choice when activity reaches a boundary. Because the signals occur on a millisecond timescale, translating to human decision-making using functional neuroimaging has been challenging. Previous neuroimaging work in humans has identified patterns of neural activity consistent with an accumulation account. However, the degree to which the accumulating neuroimaging signals reflect specific sources of perceptual evidence is unknown. Using an extended face/house discrimination task in conjunction with cognitive modeling, we tested whether accumulation signals, as measured using functional magnetic resonance imaging (fMRI), are stimulus-specific. Accumulation signals were defined as a change in the slope of the rising edge of activation corresponding with response time (RT), with higher slopes associated with faster RTs. Consistent with an accumulation account, fMRI activity in face- and house-selective regions in the inferior temporal cortex increased at a rate proportional to decision time in favor of the preferred stimulus. This finding indicates that stimulus-specific regions perform an evidence integrative function during goal-directed behavior and that different sources of evidence accumulate separately. We also assessed the decision-related function of other regions throughout the brain and found that several regions were consistent with classifications from prior work, suggesting a degree of domain generality in decision processing. Taken together, these results provide support for an integration-to-boundary decision mechanism and highlight possible roles of both domain-specific and domain-general regions in decision evidence evaluation.
authors.affiliation: Department of Psychology, University of Pittsburgh, PA, USA; Learning Research and Development Center, University of Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, University of Pittsburgh, PA, USA. Electronic address: j.tremel@pitt.edu.
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Tremel
authors.affiliation: Department of Psychology, University of Pittsburgh, PA, USA; Learning Research and Development Center, University of Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, University of Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, PA, USA; School of Psychology, Georgia Institute of Technology, Atlanta, GA, USA. Electronic address: mark.wheeler@psych.gatech.edu.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Wheeler
mesh_terms: D000328:Adult; D001931:Brain Mapping; D003657:Decision Making / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology; D000066499:Facial Recognition / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011930:Reaction Time; D013702:Temporal Lobe / Q000502:physiology*; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: decision time; diffusion model; evidence accumulation; fMRI; perceptual decision-making