Visual psychophysics and limits of visual discrimination performance in freely behaving mice

Mice are being used increasing commonly to study visually guided behaviors. To help frame the design of visual tasks in mice, we explored limits of mouse visual behavior using a touchscreen-based 2AFC orientation discrimination task in unrestrained animals. We found that mice were able to discriminate targets as small as 25°, as brief as 100 ms, and with an 9impulsivity index9 of 0.6. They were able to perform well a rudimentary visual search task, exhibiting classic psychometric curves to the relative contrast between target and foil. Using a combination of conditional accuracy analysis and drift diffusion modeling, we estimated the time for sensory encoding in mice as 300 ms, and the duration of their visual short-term memory as 1700 ms. Our results reveal surprising parallels between aspects of mouse and human visual behavior, and suggest that visual perceptual abilities of mice may be underappreciated.