RT Journal Article
A1 Pons, Carmen
A1 Mazade, Reece
A1 Jin, Jianzhong
A1 Dul, Mitchell W.
A1 Zaidi, Qasim
A1 Alonso, Jose-Manuel
T1 Neuronal mechanisms underlying differences in spatial resolution between darks and lights in human visionPons et al.
JF Journal of Vision
JO JOV
YR 2017
DO 10.1167/17.14.5
JF Journal of Vision
VO 17
IS 14
SP 5
OP 5
SN 1534-7362
AB  Artists and astronomers noticed centuries ago that humans perceive dark features in an image differently from light ones; however, the neuronal mechanisms underlying these dark/light asymmetries remained unknown. Based on computational modeling of neuronal responses, we have previously proposed that such perceptual dark/light asymmetries originate from a luminance/response saturation within the ON retinal pathway. Consistent with this prediction, here we show that stimulus conditions that increase ON luminance/response saturation (e.g., dark backgrounds) or its effect on light stimuli (e.g., optical blur) impair the perceptual discrimination and salience of light targets more than dark targets in human vision. We also show that, in cat visual cortex, the magnitude of the ON luminance/response saturation remains relatively constant under a wide range of luminance conditions that are common indoors, and only shifts away from the lowest luminance contrasts under low mesopic light. Finally, we show that the ON luminance/response saturation affects visual salience mostly when the high spatial frequencies of the image are reduced by poor illumination or optical blur. Because both low luminance and optical blur are risk factors in myopia, our results suggest a possible neuronal mechanism linking myopia progression with the function of the ON visual pathway. 
RD 6/25/2019
UL https://doi.org/10.1167/17.14.5