ABSTRACT
Across species, the optokinetic reflex (OKR) stabilizes vision during self-motion. OKR occurs when ON direction-selective retinal ganglion cells (oDSGCs) detect slow, global image motion on the retina. How oDSGC activity is integrated centrally to generate behavior remains unknown. Here, we discover mechanisms that contribute to motion encoding in vertically-tuned oDSGCs, and leverage these findings to empirically define signal transformation between retinal output and vertical OKR behavior. We demonstrate that motion encoding in vertically-tuned oDSGCs is contrast-sensitive and asymmetric for oDSGC types that prefer opposite directions. These phenomena arise from the interplay between spike threshold nonlinearities and differences in synaptic input weights, including shifts in the balance of excitation and inhibition. In behaving mice, these neurophysiological observations, along with a central subtraction of oDSGC outputs, accurately predict the trajectories of vertical OKR across stimulus conditions. Thus, asymmetric tuning across competing sensory channels can critically shape behavior.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
This revision includes the following significant additions: - Recordings from oDSGCs in response to an oscillating grating stimulus and corresponding linear predictions of OKR. - Use of two-photon targeting to replicate the original findings of asymmetric direction tuning between Superior and Inferior oDSGCs. - Discussion of the contribution of tuned excitation and inhibition to spike tuning. Major changes are indicated by blue text in the PDF.