Reversal-rate dependent differences in the EEG gamma-band during multistable visual perception.
It is an often reported observation in the literature on multistable perception that the reversal rate within a given observation time is subject to a high interindividual variability. Recently, we reported frontal gamma-band enhancement during multistable visual perception. The aim of the present study was to investigate whether changes in the gamma-band correspond to the variability of the reversal rate. Therefore, a total of 25 observers were divided into two subgroups according to their reversal rate during a 400-s observation period of a reversible pattern based on apparent motion. Subjects with more than 40 reversals within the 400-s were defined as high-rate switchers (HRS). Subjects with a reversal rate below 40 switches were defined as low-rate switchers (LRS). EEG was recorded from frontal, central, parietal, and occipital locations of both hemispheres. The results showed significantly higher gamma activity for the HRS in both phase-locked and non-phase-locked oscillations. Both subgroups showed the highest gamma amplitudes at frontal locations. The results support the involvement of attentional top-down processing in figure reversal. It is concluded that the higher gamma activity for the HRS reflects states of higher arousal, alertness and/or attention according to their fast reversal rate.
Strüber
D
D
Institute of Psychology and Cognition Research & Center for Cognitive Sciences, University of Bremen, P.O. Box 330440, D-28334, Bremen, Germany. strueber@uni-bremen.de
Basar-Eroglu
C
C
Hoff
E
E
Stadler
M
M
D000293:Adolescent; D000328:Adult; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D010775:Photic Stimulation; D012815:Signal Processing, Computer-Assisted; D014796:Visual Perception / Q000502:physiology*