title: Asymmetries of Dark and Bright Negative Afterimages Are Paralleled by Subcortical ON and OFF Poststimulus Responses.
abstract: Humans are more sensitive to luminance decrements than increments, as evidenced by lower thresholds and shorter latencies for dark stimuli. This asymmetry is consistent with results of neurophysiological recordings in dorsal lateral geniculate nucleus (dLGN) and primary visual cortex (V1) of cat and monkey. Specifically, V1 population responses demonstrate that darks elicit higher levels of activation than brights, and the latency of OFF responses in dLGN and V1 is shorter than that of ON responses. The removal of a dark or bright disc often generates the perception of a negative afterimage, and here we ask whether there also exist asymmetries for negative afterimages elicited by dark and bright discs. If so, do the poststimulus responses of subcortical ON and OFF cells parallel such afterimage asymmetries? To test these hypotheses, we performed psychophysical experiments in humans and single-cell/S-potential recordings in cat dLGN. Psychophysically, we found that bright afterimages elicited by luminance decrements are stronger and last longer than dark afterimages elicited by luminance increments of equal sizes. Neurophysiologically, we found that ON cells responded to the removal of a dark disc with higher firing rates that were maintained for longer than OFF cells to the removal of a bright disc. The ON and OFF cell asymmetry was most pronounced at long stimulus durations in the dLGN. We conclude that subcortical response strength differences between ON and OFF channels parallel the asymmetries between bright and dark negative afterimages, further supporting a subcortical origin of bright and dark afterimage perception.SIGNIFICANCE STATEMENTAfterimages are physiological aftereffects following stimulation of the eye, the study of which helps us to understand how our visual brain generates visual perception in the absence of physical stimuli. We report, for the first time to our knowledge, asymmetries between bright and dark negative afterimages elicited by luminance decrements and increments, respectively. Bright afterimages are stronger and last longer than dark afterimages. Subcortical neuronal recordings of poststimulus responses of ON and OFF cells reveal similar asymmetries with respect to response strength and duration. Our results suggest that subcortical differences between ON and OFF channels help explain intensity and duration asymmetries between bright and dark afterimages, supporting the notion of a subcortical origin of bright and dark afterimages.
authors.affiliation: Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.|University of Chinese Academy of Sciences, Shanghai 200031, China, and.
authors.forename: Hui
authors.identifier: 0000-0002-0355-5090
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.|University of Chinese Academy of Sciences, Shanghai 200031, China, and.
authors.forename: Xu
authors.identifier: 0000-0003-4631-0891
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China, i.andolina@ion.ac.cn w.wang@ion.ac.cn.
authors.forename: Ian M
authors.identifier: 0000-0001-9985-3414
authors.initials: IM
authors.lastname: Andolina
authors.affiliation: Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Li
authors.affiliation: Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Yiliang
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Neurology, University of Freiburg, 79085 Freiburg, Germany.
authors.forename: Lothar
authors.initials: L
authors.lastname: Spillmann
authors.affiliation: Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China, i.andolina@ion.ac.cn w.wang@ion.ac.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000818:Animals; D002415:Cats; D015350:Contrast Sensitivity / Q000502:physiology*; D005829:Geniculate Bodies / Q000166:cytology; D006801:Humans; D008297:Male; D009474:Neurons / Q000502:physiology; D010470:Perceptual Masking / Q000502:physiology*; D010775:Photic Stimulation; D011601:Psychophysics; D011930:Reaction Time; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*; D055815:Young Adult
keywords: LGN; OFF; ON; afterimage; asymmetry