More recently, several groups have started using rodents to tackle such questions ( Brunton et al., 2013 Carandini and Churchland, 2013 Raposo et al., 2014 Hanks et al., 2015 Scott et al., 2015 Morcos and Harvey, 2016 Licata et al., 2017 Odoemene et al., 2017). However, much remains unknown regarding which brain areas are involved, and the specific circuit mechanisms and dynamics underlying this computation ( Brody and Hanks, 2016). How the brain gradually accumulates sensory evidence has been the topic of extensive studies performed primarily in primates ( Gold and Shadlen, 2007). Here, the mouse must find its food source while navigating in a potentially changing environment the corn plant may turn out to be a scarecrow, and evidence for or against this is typically used to interactively update a motor plan. This example also highlights another important point about decision-making, namely that it is often performed in conjunction with other complex behaviors and can itself be a dynamic process occurring over seconds-long timescales. Amidst tall grass, deciding a route to a partially occluded food source (say, a corn plant) might require gradual accumulation of visual evidence, i.e., short glimpses of what may or may not be part of that plant. Take, for instance, a mouse in the wild, whose navigation behavior relies on vision ( Alyan and Jander, 1994 Etienne et al., 1996 Stopka and Macdonald, 2003). Making decisions based on noisy or ambiguous sensory evidence is a task animals must face on a daily basis. Our task, which can be readily integrated with state-of-the-art techniques, is thus a valuable tool to study the circuit mechanisms and dynamics underlying perceptual decision making, particularly under more complex behavioral contexts. Additionally, analysis of the mice's running patterns revealed that trajectories are fairly stereotyped yet modulated by the amount of sensory evidence, suggesting that the navigational component of this task may provide a continuous readout correlated to the underlying cognitive variables. Moreover, using non-parametric as well as modeling approaches, we show that the mice indeed accumulate evidence: they use multiple pulses of evidence from throughout the cue region of the maze to make their decision, albeit with a small overweighting of earlier cues, and their performance is affected by the magnitude but not the duration of evidence. They are sensitive to side differences of a single pulse, and their memory of the cues is stable over time. A large number of mice of different genotypes were able to learn and consistently perform the task, at levels similar to rats in analogous tasks. The pulses occur randomly with Poisson statistics, yielding a diverse yet well-controlled stimulus set, making the data conducive to a variety of computational approaches. As they navigate down the stem of a virtual T-maze, they see brief pulses of visual evidence on either side, and retrieve a reward on the arm with the highest number of pulses. Here, we describe a new evidence-accumulation task for head-fixed mice navigating in a virtual reality (VR) environment. Given the wide availability of genetic and optical tools for mice, they can be useful model organisms for the study of these phenomena however, behavioral tools are largely lacking. The gradual accumulation of sensory evidence is a crucial component of perceptual decision making, but its neural mechanisms are still poorly understood. 6Howard Hughes Medical Institute, Princeton University, Princeton, NJ, United States.5Department of Molecular Biology, Princeton University, Princeton, NJ, United States. ![]() 4Department of Psychology, Princeton University, Princeton, NJ, United States.3Bezos Center for Neural Dynamics, Princeton University, Princeton, NJ, United States.2Robert Wood Johnson Medical School, New Brunswick, NJ, United States.1Princeton Neuroscience Institute, Princeton University, Princeton, NJ, United States.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |