Unconscious orientation processing.
Recent findings have shown that certain attributes of visual stimuli, like orientation, are registered in cortical areas when the stimulus is unresolvable or perceptually invisible; however, there is no evidence to show that complex forms of orientation processing (e.g., modulatory effects of orientation on the processing of other features) could occur in the absence of awareness. To address these questions, different psychophysical paradigms were designed in six experiments to probe unconscious orientation processing. First we demonstrated orientation-selective adaptation and color-contingent orientation adaptation for peripheral unresolvable Gabor patches. The next experiments showed the modulatory effects of perceptually indiscriminable orientations on apparent motion processing and attentional mechanisms. Finally we investigated disappearance patterns of unresolvable Gabor stimuli during motion-induced blindness (MIB). Abrupt changes in local unresolvable orientations truncated MIB; however, orientation-based grouping failed to affect the MIB pattern when the orientations were unresolvable. Overall results revealed that unresolvable orientations substantially influence perception at multiple levels.
Department of Cognitive Neuroscience, School of Intelligent Systems, Iranian Institute for Studies in Theoretical Physics and Mathematics, Niavaran, P.O. Box 19395-5746, Tehran, Iran. rajimehr@ipm.ir
Reza
R
Rajimehr
D000222:Adaptation, Physiological / Q000502:physiology; D002540:Cerebral Cortex / Q000502:physiology*; D003463:Cues; D006801:Humans; D009039:Motion Perception / Q000502:physiology; D009483:Neuropsychological Tests; D009949:Orientation / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D013028:Space Perception / Q000502:physiology; D014473:Unconscious, Psychology; D014796:Visual Perception / Q000502:physiology*