The electrophysiological correlates of stimulus visibility and metacontrast masking.
There are conflicting views concerning the electrophysiological correlates of visual consciousness. Whereas one view considers a relatively late positive deflection (LP) as a primary correlate of consciousness, another model links consciousness with earlier negativity (VAN). The present experiment utilized metacontrast masking in investigating the electrophysiological correlates of visual consciousness. The participants were presented with target-mask sequences in three stimulus onset asynchronies. The target stimuli were followed by either a metacontrast mask or a similar-looking, but ineffective pseudomask. The results showed that the first deflection that correlated with target visibility was VAN which was followed by LP. We argue that the VAN is the primary correlate target visibility, while the LP reflects later, postperceptual processing stages.
Railo
Henry
H
Department of Psychology, University of Turku, 20014 Turku, Finland. henry.railo@utu.fi
Koivisto
Mika
M
D000328:Adult; D001288:Attention / Q000502:physiology*; D001364:Awareness / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology; D004192:Discrimination, Psychological / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010470:Perceptual Masking / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult