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Jean Lorenceau, Charles Aissani, Jacques Martinerie, Lydia Yahia Cherif, Anne-Lise Paradis; MEG Beta band oscillations index perceptual form/motion integration . Journal of Vision 2014;14(10):295. doi: https://doi.org/10.1167/14.10.295.
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© ARVO (1962-2015); The Authors (2016-present)
Scalp recordings of electrophysiological oscillations in humans reveal activity in different frequency bands correlated to perceptual, attentional, motor and cognitive processes. To probe the hypothetical roles of Gamma and Beta band activity in perceptual form/motion binding, we conducted a MEG study on 12 healthy participants using visual moving stimuli that, depending on subtle modifications of the distribution of luminance, could either be perceived as a whole square-shape moving along a Lissajou's figure (bound percept) or as two pairs of bars oscillating independently along horizontal and vertical axes (unbound percept). Each pair of bars moved at different frequencies (2.3 & 3Hz), so as to evoke different tagged cortical responses. After each trial, participants were to report their percept as bound, unbound (or unclassified). Randomizing the position of color coded responses required remapping the motor response on each trial, thus avoiding motor preparation that could contaminate the data. We report evoked tagged responses at the fundamentals and 1st harmonics of oscillations frequencies in parieto-occipital cortex independently from perception and identified significant differences in frontal sources at a 10.6 Hz intermodulation product for bound as compared to unbound percepts. Further, enhanced bilateral parietal Beta power (15-25 Hz) for bound as compared to unbound states and trial-by-trial classification of perception from Beta power suggest Beta oscillations provide a marker of perceptual states. Activity in the Alpha (8-12 Hz) and Gamma band (40-80 Hz), although significantly different during visual stimulation than during baseline, did not distinguish perceptual states. Our results indicate that Beta activity index perceptual states and favor the view that Beta oscillations serve to facilitate the long-range communication involved in integrating moving elements into a global object motion across both hemispheres.
Meeting abstract presented at VSS 2014
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