How neuronal computations in the sensory periphery contribute to computations in the
cortex is not well understood. We examined this question in the context of visual-motion
processing in the retina and primary visual cortex (V1) of mice. We disrupted retinal
direction selectivity, either exclusively along the horizontal axis using FRMD7 mutants
or along all directions by ablating starburst amacrine cells, and monitored neuronal
activity in layer 2/3 of V1 during stimulation with visual motion. In control mice,
we found an over-representation of cortical cells preferring posterior visual motion,
the dominant motion direction an animal experiences when it moves forward. In mice
with disrupted retinal direction selectivity, the over-representation of posterior-motion-preferring
cortical cells disappeared, and their responses at higher stimulus speeds were reduced.
This work reveals the existence of two functionally distinct, sensory-periphery-dependent
and -independent computations of visual motion in the cortex.
