A simple retinal mechanism contributes to perceptual interactions between rod- and cone-mediated responses in primates

• Published in: eLife 2015-06, Vol.4
• Main Authors: Grimes, William N, Graves, Logan R, Summers, Mathew T, Rieke, Fred
• Format: Article
• Language: English
• Subjects: Animals; Experiments; Light effects; Light emitting diodes; mesopic vision; Monkeys & apes; neural computation; Neuroscience; Nonlinear systems; parallel processing; Photoreceptors; primate; Primates; Psychophysics; Retina; Retina - physiology; Retinal Cone Photoreceptor Cells - physiology; Retinal ganglion cells; Retinal Ganglion Cells - physiology; Retinal Rod Photoreceptor Cells - physiology; Short Report; Vision, Ocular; Visual pathways; Visual perception
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.08033

Visual perception across a broad range of light levels is shaped by interactions between rod- and cone-mediated signals. Because responses of retinal ganglion cells, the output cells of the retina, depend on signals from both rod and cone photoreceptors, interactions occurring in retinal circuits provide an opportunity to link the mechanistic operation of parallel pathways and perception. Here we show that rod- and cone-mediated responses interact nonlinearly to control the responses of primate retinal ganglion cells; these nonlinear interactions, surprisingly, were asymmetric, with rod responses strongly suppressing subsequent cone responses but not vice-versa. Human psychophysical experiments revealed a similar perceptual asymmetry. Nonlinear interactions in the retinal output cells were well-predicted by linear summation of kinetically-distinct rod- and cone-mediated signals followed by a synaptic nonlinearity. These experiments thus reveal how a simple mechanism controlling interactions between parallel pathways shapes circuit output and perception.