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Updated: Jun 25, 2025
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Transpupillary Two-Photon In Vivo Imaging of the Mouse Retina
Published on: February 13, 2021
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Primate retina trades single-photon detection for high-fidelity contrast encoding
Markku Kilpeläinen1,2, Johan Westö3, Jussi Tiihonen2,3
1Department of Psychology and Logopedics, University of Helsinki, Helsinki, Finland.
Nature Communications
|May 27, 2024
Summary
Human vision at its sensitivity limit relies on the ON retinal pathway, not the OFF pathway. This explains why we can detect light intensity differences but not single photons in darkness.
Area of Science:
- Neuroscience
- Vision Science
- Retinal Physiology
Background:
- The precise relationship between retinal ganglion cell activity and human visual perception remains unclear.
- Understanding visual perception at the limits of sensitivity is crucial for comprehending visual processing.
- The roles of distinct retinal pathways, like ON and OFF parasol cells, in perception are not fully elucidated.
Purpose of the Study:
- To investigate how retinal spike output, specifically from ON and OFF parasol cells, relates to human visual perception at the threshold of vision.
- To determine which retinal pathway is critical for visual detection at the lowest light levels.
Main Methods:
- Correlating human psychophysical perception with electrophysiological recordings of primate retinal ganglion cell (RGC) spike output.
- Utilizing precisely controlled stimulus conditions to match perceptual tasks with RGC responses.
- Analyzing the contribution of both ON and OFF magnocellular pathways to visual detection.
Main Results:
- Human vision at its ultimate sensitivity limit is dependent on the spike output of the ON retinal pathway.
- The OFF retinal pathway does not contribute to visual perception at this sensitivity limit.
- Nonlinear signal processing within the ON pathway prevents single-photon detection in darkness.
Conclusions:
- The ON retinal pathway is essential for human visual perception at the threshold of light detection.
- The observed nonlinearities in the ON pathway allow for the discrimination of light intensity differences, despite limiting the detection of individual photons.
- These findings provide critical insights into the neural basis of vision at its most sensitive range.
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