Visual attention and metacontrast modify latency to perception in opposite directions.
In human observers, cue-induced visual attention ('bottom-up' transient focal attention) shortens the latency of perception. Metacontrast reduces the intensity of perception and can even obliterate it. We show that a close relationship exists between both, but that their effects are reversed: cue-induced visual attention not only shortens latency but also intensifies perception, and metacontrast not only lowers intensity of perception but also prolongs latency. A common neurophysiological mechanism for both is possible. Indirect evidence suggests that this could be a subthreshold modulation of neuronal thresholds by de- and hyperpolarization.
Kirschfeld
K
K
Max-Planck-Institut für biologische Kybernetik, Spemannstrasse 38, D-72076, Tübingen, Germany. kuno.kirschfeld@tuebingen.mpg.de
Kammer
T
T
D000328:Adult; D001288:Attention / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology; D009903:Optical Illusions / Q000502:physiology; D010470:Perceptual Masking / Q000502:physiology; D011930:Reaction Time; D014796:Visual Perception / Q000502:physiology*