The role of contrast adaptation in saccadic suppression in humans.
The idea of retinal and ex-retinal sources of saccadic suppression has long been established in previous studies. However, how they are implemented in local circuit remains unknown. Researchers have suggested that saccadic suppression was probably achieved by contrast gain control, but this possibility has never been directly tested. In this study, we manipulated contrast gain control by contrast-adapting observers with sinusoidal gratings of different contrasts. Presaccadic and fixational contrast thresholds were measured and compared to give estimates of saccadic suppression at different adaptation states. Our results reconfirmed the selective saccadic suppression in achromatic condition, and further showed that, achromatic saccadic suppression diminished as contrast adaptation was accentuated, whereas no significant chromatic saccadic suppression was induced by greater contrast adaptation. Our data provided evidence for the involvement of contrast gain control in saccadic suppression in achromatic channel. We also discussed how the negative correlation between contrast adaptation and saccadic suppression could be interpreted with contrast gain control.
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ; University of Chinese Academy of Sciences, Beijing, China.
Xiao-Jing
XJ
Gu
Department of Neurobiology and Anatomy, University of Texas-Houston Medical School, Houston, Texas, United States of America.
Ming
M
Hu
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
Bing
B
Li
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China ; Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Science, Kunming, Yunnan, China.
Xin-Tian
XT
Hu
D000222:Adaptation, Physiological; D000328:Adult; D015350:Contrast Sensitivity; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D012438:Saccades / Q000502:physiology*