Neuronal and perceptual differences in the temporal processing of darks and lights.
Visual information is mediated by two major thalamic pathways that signal light decrements (OFF) and increments (ON) in visual scenes, the OFF pathway being faster than the ON. Here, we demonstrate that this OFF temporal advantage is transferred to visual cortex and has a correlate in human perception. OFF-dominated cortical neurons in cats responded ∼3 ms faster to visual stimuli than ON-dominated cortical neurons, and dark-mediated suppression in ON-dominated neurons peaked ∼14 ms faster than light-mediated suppression in OFF-dominated neurons. Consistent with the neuronal differences, human observers were 6-14 ms faster at detecting darks than lights and better at discriminating dark than light flickers. Neuronal and perceptual differences both vanished if backgrounds were biased toward darks. Our results suggest that the cortical OFF pathway is faster than the ON pathway at increasing and suppressing visual responses, and these differences have parallels in the human visual perception of lights and darks.
Graduate Center for Vision Research, SUNY College of Optometry, New York, NY, 10036, USA.
Stanley Jose
SJ
Komban
Graduate Center for Vision Research, SUNY College of Optometry, New York, NY, 10036, USA.
Jens
J
Kremkow
Graduate Center for Vision Research, SUNY College of Optometry, New York, NY, 10036, USA.
Jianzhong
J
Jin
Graduate Center for Vision Research, SUNY College of Optometry, New York, NY, 10036, USA.
Yushi
Y
Wang
Graduate Center for Vision Research, SUNY College of Optometry, New York, NY, 10036, USA; School of Electrical Engineering, Iran University of Science and Technology, Narmak, Tehran, Iran.
Reza
R
Lashgari
Graduate Center for Vision Research, SUNY College of Optometry, New York, NY, 10036, USA.
Xiaobing
X
Li
Graduate Center for Vision Research, SUNY College of Optometry, New York, NY, 10036, USA.
Qasim
Q
Zaidi
Graduate Center for Vision Research, SUNY College of Optometry, New York, NY, 10036, USA. Electronic address: jalonso@sunyopt.edu.
Jose-Manuel
JM
Alonso
D000818:Animals; D001921:Brain; D001931:Brain Mapping; D002415:Cats; D003624:Darkness; D008027:Light; D008297:Male; D009474:Neurons / Q000502:physiology*; D010775:Photic Stimulation; D011601:Psychophysics; D011930:Reaction Time / Q000502:physiology; D013997:Time Factors; D014793:Visual Cortex / Q000166:cytology*; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*