Range, routing and kinetics of rod signaling in primate retina
Abstract
Stimulus- or context-dependent routing of neural signals through parallel pathways can permit flexible processing of diverse inputs. For example, work in mouse shows that rod photoreceptor signals are routed through several retinal pathways, each specialized for different light levels. This light-level-dependent routing of rod signals has been invoked to explain several human perceptual results, but it has not been tested in primate retina. Here we show, surprisingly, that rod signals traverse the primate retina almost exclusively through a single pathway - the dedicated rod bipolar pathway. Identical experiments in mouse and primate reveal substantial differences in how rod signals traverse the retina. These results require reevaluating human perceptual results in terms of flexible computation within this single pathway. This includes a prominent speeding of rod signals with light level - which we show is inherited directly from the rod photoreceptors themselves rather than from different pathways with distinct kinetics.
Data availability
We have provided source data for the population analysis for all the main figures (as Excel files) and the raw traces from Figure 2 (Figure 2-source data 2 and Figure 2-source data 3).
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Author details
Funding
National Institutes of Health
- Fred Rieke
Howard Hughes Medical Institute
- Fred Rieke
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: We obtained primate retinas (Macaca fascicularis, Macaca nemestrina and Macaca mulatta of either sex, ages 3-19 years) through the Tissue Distribution Program of the Regional Primate Research Center. All protocols were approved by the Institutional Animal Care and Use Committee at the University of Washington (protocol 4140-01).
Copyright
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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