Distinct inhibitory pathways control velocity and directional tuning in the mouse retina

Summers, Mathew T.; Feller, Marla B.

doi:10.1016/j.cub.2022.03.054

Cited by 11 publications

(10 citation statements)

References 61 publications

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“…Further insight into how oDSGCs encode motion can be gained by comparing their tuning properties to those of the more comprehensively studied ooDSGCs. While prior work has focused on speed tuning as the primary difference between oDSGCs and ooDSGCs 14,26,49,57,79 , our results reveal an additional difference between these two classes of DSGCs that has been previously overlooked: oDSGCs are contrast-sensitive ( Fig 7 ), whereas ooDSGCs are not 62 . In ooDSGCs, preservation of E/I across contrasts is apparently critical for retaining contrast-invariant direction tuning 61,63 .…”

Section: Discussioncontrasting

confidence: 58%

“…These conductances have been studied primarily in ooDSGCs and deserve further characterization in oDSGCs. Interestingly, VGluT3 amacrine cells also corelease glycine, which cancels oDSGC spiking in response to high-velocity stimuli 49,57,78,79 . Asymmetries at the VGluT3-oDSGC synapse could coincide with differences in the speed tuning properties of Superior and Inferior oDSGCs.…”

Section: Discussionmentioning

confidence: 99%

“…In addition to the gain of excitatory inputs, other mechanisms could contribute to tuning curve differences between Superior and Inferior oDSGCs. Debate remains over the extent to which excitatory inputs to DSGCs are directionally tuned 48,50,[54][55][56][57][58] . Our data indicate that excitation may be less direction selective in Superior than in Inferior oDSGCs ( Further insight into how oDSGCs encode motion can be gained by comparing their tuning properties to those of the more comprehensively studied ooDSGCs.…”

Section: Discussionmentioning

confidence: 99%

“…Less obvious, however, is whether this difference in excitatory input can also account for the wider tuning curves of Superior oDSGCs (Fig 2h-l). A debate remains over whether excitatory inputs to DSGCs are directionally tuned 48,50,[54][55][56][57][58] (reviewed by ref. 27 ).…”

Section: Untuned Excitation Broadens Spike Tuning Curvesmentioning

confidence: 99%

“…First, the membrane capacitances of Superior oDSGCs were greater than those of Inferior oDSGCs ( 3 ). A debate remains over whether excitatory inputs to DSGCs are directionally tuned 48,50,[54][55][56][57][58] (reviewed by Wei 27 ). While our results indicate that MTN-projecting RGCs might receive different amounts of excitation based on stimulus direction ( Fig 3H ), the majority of directionally tuned inputs were inhibitory ( Fig 3K ).…”

Section: Postsynaptic Differences May Account For Shifts In E/imentioning

confidence: 99%

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Asymmetric retinal direction tuning predicts optokinetic eye movements across stimulus conditions

Harris

Dunn

2022

Preprint

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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. Specifically, 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 direction and magnitude of vertical OKR across stimulus conditions. Thus, asymmetric synaptic input across competing sensory input channels can critically shape behavior.

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