High-yield methods for accurate two-alternative visual psychophysics in head-fixed mice
Research in neuroscience relies increasingly on the mouse, a mammalian species that affords unparalleled genetic tractability and brain atlases. Here we introduce high-yield methods for probing mouse visual decisions. Mice are head-fixed, which facilitates repeatable visual stimulation, eye tracking, and brain access. They turn a steering wheel to make two-alternative choices, forced or unforced. Learning is rapid thanks to intuitive coupling of stimuli to wheel position. The mouse decisions deliver high-quality psychometric curves for detection and discrimination, and conform to the predictions of a simple probabilistic observer model. The task is readily paired with two-photon imaging of cortical activity. Optogenetic inactivation reveals that the task requires the visual cortex. Mice are motivated to perform the task by fluid reward or optogenetic stimulation of dopaminergic neurons. This stimulation elicits larger number of trials and faster learning. These methods provide a platform to accurately probe mouse vision and its neural basis.