Beta, but not gamma, band oscillations index visual form-motion integration.
Electrophysiological oscillations in different frequency bands co-occur with perceptual, motor and cognitive processes but their function and respective contributions to these processes need further investigations. Here, we recorded MEG signals and seek for percept related modulations of alpha, beta and gamma band activity during a perceptual form/motion integration task. Participants reported their bound or unbound perception of ambiguously moving displays that could either be seen as a whole square-like shape moving along a Lissajou's figure (bound percept) or as pairs of bars oscillating independently along cardinal axes (unbound percept). We found that beta (15-25 Hz), but not gamma (55-85 Hz) oscillations, index perceptual states at the individual and group level. The gamma band activity found in the occipital lobe, although significantly higher during visual stimulation than during base line, is similar in all perceptual states. Similarly, decreased alpha activity during visual stimulation is not different for the different percepts. Trial-by-trial classification of perceptual reports based on beta band oscillations was significant in most observers, further supporting the view that modulation of beta power reliably index perceptual integration of form/motion stimuli, even at the individual level.
Université Pierre et Marie Curie, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, CNRS UMR7225, Paris, France.
Charles
C
Aissani
Université Pierre et Marie Curie, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, CNRS UMR7225, Paris, France.
Jacques
J
Martinerie
CENIR, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, Université Pierre et Marie Curie-Paris6, INSERM U975, CNRS UMR7225, Paris, France.
Lydia
L
Yahia-Cherif
Université Pierre et Marie Curie, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, CNRS UMR7225, Paris, France.
Anne-Lise
AL
Paradis
Université Pierre et Marie Curie, Centre de Recherche de l'Institut du Cerveau et de la Moelle épinière, CNRS UMR7225, Paris, France.
Jean
J
Lorenceau
D000328:Adult; D004569:Electroencephalography; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D009038:Motion; D055815:Young Adult