Sources of noise during accumulation of evidence in unrestrained and voluntarily head-restrained rats
Benjamin B Scott,
Christine M Constantinople,
Jeffrey C Erlich,
David W Tank,
Carlos D Brody
Affiliations
Benjamin B Scott
Princeton Neuroscience Institute, Princeton University, Princeton, United States; Department of Molecular Biology, Princeton University, Princeton, United States
Christine M Constantinople
Princeton Neuroscience Institute, Princeton University, Princeton, United States; Department of Molecular Biology, Princeton University, Princeton, United States
NYU-ECNU Institute of Brain and Cognitive Science, New York University Shanghai, Shanghai, China
David W Tank
Princeton Neuroscience Institute, Princeton University, Princeton, United States; Department of Molecular Biology, Princeton University, Princeton, United States; Bezos Center for Neural Circuit Dynamics, Princeton University, Princeton, United States
Carlos D Brody
Princeton Neuroscience Institute, Princeton University, Princeton, United States; Department of Molecular Biology, Princeton University, Princeton, United States; Howard Hughes Medical Institute, Princeton University, Princeton, United States
Decision-making behavior is often characterized by substantial variability, but its source remains unclear. We developed a visual accumulation of evidence task designed to quantify sources of noise and to be performed during voluntary head restraint, enabling cellular resolution imaging in future studies. Rats accumulated discrete numbers of flashes presented to the left and right visual hemifields and indicated the side that had the greater number of flashes. Using a signal-detection theory-based model, we found that the standard deviation in their internal estimate of flash number scaled linearly with the number of flashes. This indicates a major source of noise that, surprisingly, is not consistent with the widely used 'drift-diffusion modeling' (DDM) approach but is instead closely related to proposed models of numerical cognition and counting. We speculate that this form of noise could be important in accumulation of evidence tasks generally.
