October 31, 2020

Retinal mechanisms of saccadic suppression and their role in processing sequential stimuli

Visual perception remains stable across eye movements such as saccades, despite the concurrent strong disruptive visual flow. This stability is partially associated with a reduction in visual system sensitivity, a phenomenon known as saccadic suppression. Saccadic suppression already starts in the retina, where responses of ganglion cells to flashes are strongly suppressed after saccade like image shifts. However, the retinal circuit mechanisms giving rise to such suppression remain unknown. Here, we describe these mechanisms using electrophysiology in mouse, pig, and macaque retina, 2 photon calcium imaging, computational modeling, and human psychophysics. We find that several mechanisms support retinal saccadic suppression, including a novel retinal processing motif, "dynamic reversal suppression", which is triggered by sequential stimuli containing contrast reversals. This motif relies on nonlinear transformation of the inherently slow responses of cone photoreceptors. We describe two further components of suppression present in ON ganglion cells which originate in the cells’ receptive field surround, highlighting a novel disparity between ON and OFF ganglion cells. Our results increase our understanding of retinal processing of any time varying stimulus.

 bioRxiv Subject Collection: Neuroscience

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