Threshold vision under full-field stimulation: Revisiting the minimum number of quanta necessary to evoke a visual sensation
| Autor: | Prakash Adhikari, Andrew J. Zele, Ashim Dey, Beatrix Feigl |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Retinal Bipolar Cells
Photon genetic structures Absolute threshold Stimulus (physiology) Summation Retinal ganglion Retina 050105 experimental psychology Rod 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Optics 0501 psychology and cognitive sciences Scotopic vision Night Vision Vision Ocular Physics business.industry 05 social sciences Retinal Sensory Systems Ophthalmology Amacrine Cells chemistry sense organs business 030217 neurology & neurosurgery |
| Zdroj: | Vision Research. 180:1-10 |
| ISSN: | 0042-6989 |
| Popis: | At the absolute threshold of vision, Hecht, Shlaer and Pirenne estimate that 5–14 photons are absorbed within a retinal area containing ~500 rods. Other estimates of scotopic threshold vision based on stimuli with different durations and focal areas range up to ~100,000 photons. Given that rod density varies with retinal eccentricity and the magnitude of the intrinsic noise increases with increasing stimulus area and duration, here we determine whether the scotopic threshold estimates with focal stimuli can be extended to full-field stimulation and whether summation explains inter-study differences. We show that full-field threshold vision (~1018 mm2, 10 ms duration) is more sensitive than at absolute threshold, requiring the absorption of ~1000 photons across ~91.96 million rods. A summation model is presented integrating our and published data and using a nominal exposure duration, criterion frequency of seeing, rod density, and retinal area that largely explains the inter-study differences and allows estimation of rods per photon ratio for any stimulus size and duration. The highest signal to noise ratio is defined by a peak rod convergence estimated at 53:4:1:2 (rods:rod bipolar cells:AII amacrine cells:retinal ganglion cells), in line with macaque anatomical estimates that show AII amacrine cells form the bottleneck in the rod pathway to set the scotopic visual limit. Our model estimations that the rods per photon ratio under full-field stimulation is ~3000X higher than at absolute threshold are in accordance with visual summation effects and provide an alternative approach for understanding the limits of scotopic vision. |
| Databáze: | OpenAIRE |
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