Natural binocular depth discrimination behavior in mice explained by visual cortical activity

In mice and other mammals, forebrain neurons integrate right and left eye information to generate a three-dimensional representation of the visual environment. Neurons in the visual cortex of mice are sensitive to binocular disparity,(1-3) yet it is unclear whether that sensitivity is linked to the perception of depth.(4-8) We developed a natural task based on the classic visual cliff and pole descent tasks to estimate the psychophysical range of mouse depth discrimination.(5,9) Mice with binocular vision descended to a near (shallow) surface more often when surrounding far (deep) surfaces were progressively more distant. Occlusion of one eye severely impaired their ability to target the near surface. We quantified the distance at which animals make their decisions to estimate the binocular image displacement of the checkerboard pattern on the near and far surfaces. Then, we assayed the disparity sensitivity of large populations of binocular neurons in primary visual cortex (V1) using two-photon microscopy(2) and quantitatively compared this information available in V1 to their behavioral sensitivity. Disparity information in V1 matches the behavioral performance over the range of depths examined and was resistant to changes in binocular alignment. These findings reveal that mice naturally use stereoscopic cues to guide their behavior and indicate a neural basis for this depth discrimination task.

Automated summary

In mice, neurons in the visual cortex are sensitive to binocular disparity, but it was uncertain if this sensitivity was related to depth perception. A study developed a natural task to estimate mouse depth discrimination, finding that mice naturally use stereoscopic cues to guide their behavior. Neural basis for depth discrimination task in mice was indicated by the findings.