Volberg, Gregor and Wutz, Andreas and Greenlee, Mark W. (2013) Top-Down Control in Contour Grouping. PLOS ONE, 8 (1): e54085. ISSN 1932-6203,
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Human observers tend to group oriented line segments into full contours if they follow the Gestalt rule of 'good continuation'. It is commonly assumed that contour grouping emerges automatically in early visual cortex. In contrast, recent work in animal models suggests that contour grouping requires learning and thus involves top-down control from higher brain structures. Here we explore mechanisms of top-down control in perceptual grouping by investigating synchronicity within EEG oscillations. Human participants saw two micro-Gabor arrays in a random order, with the task to indicate whether the first (S1) or the second stimulus (S2) contained a contour of collinearly aligned elements. Contour compared to non-contour S1 produced a larger posterior post-stimulus beta power (15-21 Hz). Contour S2 was associated with a pre-stimulus decrease in posterior alpha power (11-12 Hz) and in fronto-posterior theta (4-5 Hz) phase couplings, but not with a post-stimulus increase in beta power. The results indicate that subjects used prior knowledge from S1 processing for S2 contour grouping. Expanding previous work on theta oscillations, we propose that long-range theta synchrony shapes neural responses to perceptual groupings regulating lateral inhibition in early visual cortex.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | FIGURE-GROUND ORGANIZATION; PRIMARY VISUAL-CORTEX; EEG ALPHA OSCILLATIONS; SPATIAL ATTENTION; ELECTROPHYSIOLOGICAL CORRELATE; BEHAVIORAL PERFORMANCE; THETA OSCILLATIONS; OCCIPITAL CORTEX; CORTICAL AREA; GLOBAL SHAPES; |
| Subjects: | 100 Philosophy & psychology > 150 Psychology |
| Divisions: | Human Sciences > Institut für Psychologie Human Sciences > Institut für Psychologie > Lehrstuhl für Psychologie I (Allgemeine Psychologie I und Methodenlehre) - Prof. Dr. Mark W. Greenlee |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 28 Apr 2020 07:32 |
| Last Modified: | 28 Apr 2020 07:32 |
| URI: | https://pred.uni-regensburg.de/id/eprint/17293 |
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