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Updated: Jun 7, 2025
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Transretinal ERG Recordings from Mouse Retina: Rod and Cone Photoresponses
Published on: March 14, 2012
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Rod inputs arrive at horizontal cell somas in mouse retina solely via rod-cone coupling
Wallace B Thoreson1,2, Asia L Sladek1,2, Cody L Barta1
1Truhlsen Eye Institute and Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE 68106, USA.
Biorxiv : the Preprint Server for Biology
|November 18, 2024
Summary
Rod signals reach horizontal cell somas via cones, not directly down the axon. This occurs through rod-cone gap junctions, enabling spectrally opponent interactions in the retina.
Area of Science:
- Neuroscience
- Retinal Physiology
- Phototransduction
Background:
- Horizontal cells integrate signals from photoreceptors in the retina.
- Rod and cone photoreceptors synapse onto different retinal horizontal cell compartments.
- Previous studies proposed rod signals travel down axons to somata for spectral opponency, but data were conflicting.
Purpose of the Study:
- To investigate the pathway of rod signals to horizontal cell somata in the mouse retina.
- To determine if rod signals travel down the axon or are relayed by cones.
Main Methods:
- Optogenetic stimulation using channelrhodopsin selectively expressed in rods and/or cones.
- Analysis of inward currents in horizontal cell somata.
- Cone-specific synaptotagmin 1 knockout to block cone synaptic release.
- Elimination of Cx36 gap junctions between rods and cones.
Main Results:
- Optogenetic stimulation of rods and cones evoked inward currents in horizontal cell somata.
- Rod-driven responses in somata were independent of rod synaptic release but dependent on cone release.
- Eliminating rod-cone gap junctions (Cx36) abolished rod-driven responses in horizontal somata.
- Cone-specific synaptotagmin 1 knockout abolished cone-driven responses.
Conclusions:
- Rod signals reach B-type horizontal cell somas exclusively through gap junctions with cones.
- Rod signals do not travel down the axon from the axon terminal to the soma.
- This pathway facilitates spectrally opponent interactions between rods and cones.
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