Timing of contextual modulation in the shine-through effect.
Contextual elements can fundamentally change the perception of an embedded target. A recently discovered masking effect, shine-through, allows one to investigate the precise dynamics of contextual modulation of the human visual system. In this shine-through effect, a vernier precedes a grating comprising more than seven elements for display times as short as 10 ms. The vernier appears as a "shine-through" element superimposed on the grating. However, if additional single lines are presented above and below the grating, visibility of the shine-through element dramatically diminishes. Recent publications focused mainly on the spatial aspects of this contextual modulation. Here, we investigate its temporal characteristics. We show that contextual suppression can occur for context durations of 5-10 ms, even if contextual elements appear 100 ms before target onset. This contextual suppression is not due to the presentation of the contextual elements themselves since without the grating contextual elements exert only weak masking power. Only the combination of contextual elements and grating causes the contextual suppression.
Herzog
Michael H
MH
Human Neurobiology, Center for Advanced Imaging, University of Bremen, Argonnenstr. 3, D-28211, Bremen, Germany. michael.herzog@uni-bremen.de
Schmonsees
Ulrike
U
Fahle
Manfred
M
D000360:Afterimage / Q000502:physiology*; D004056:Differential Threshold / Q000502:physiology; D006801:Humans; D009903:Optical Illusions; D010470:Perceptual Masking / Q000502:physiology; D013028:Space Perception / Q000502:physiology*; D013997:Time Factors