Abstract
The perceived intensity of sensory stimuli is reduced when these stimuli are caused by the observer's actions. This phenomenon is traditionally explained by forward models of sensory action-outcome, which arise from motor processing. Although these forward models critically predict anticipatory modulation of sensory neural processing, neurophysiological evidence for anticipatory modulation is sparse and has not been linked to perceptual data showing sensory attenuation. By combining a psychophysical task involving contrast discrimination with source-level time-frequency analysis of MEG data, we demonstrate that the amplitude of alpha-oscillations in visual cortex is enhanced before the onset of a visual stimulus when the identity and onset of the stimulus are controlled by participants' motor actions. Critically, this prestimulus enhancement of alpha-amplitude is paralleled by psychophysical judgments of a reduced contrast for this stimulus. We suggest that alpha-oscillations in visual cortex preceding self-generated visual stimulation are a likely neurophysiological signature of motor-induced sensory anticipation and mediate sensory attenuation. We discuss our results in relation to proposals that attribute generic inhibitory functions to alpha-oscillations in prioritizing and gating sensory information via top-down control.
Highlights
Immediate consequences of voluntary actions are subject to sensory attenuation
Sensory attenuation is often explained by consistency between forward models of anticipated action effects and actual sensory feedback
We demonstrate that causal control over both onset and identity of visual stimuli results in enhanced anticipatory alpha-power in visual cortex, an enhancement we link to a psychophysical measure of sensory attenuation
Summary
Immediate consequences of voluntary actions are subject to sensory attenuation. A prominent example is the perceived intensity of self-applied tactile stimuli, which is reduced when compared with identical, externally generated stimuli (Bays, Wolpert, & Flanagan, 2005). Other studies of sensory attenuation are based on a task design that introduces another potential confounding factor These studies typically compare stimuli that are contingent on an action with identical stimuli that are not preceded by a motor response (e.g., Weiss et al, 2011; see Hughes et al, 2012, for a review). Related functions have been proposed for sensory attenuation, namely the prevention of self-induced desensitization and the prioritizing of externally caused stimuli (Lally & Frendo, 2011; Poulet & Hedwig, 2007) On this basis, we hypothesized that anticipation of a visual stimulus that is controlled by ones action would be reflected in an increase in alpha-amplitude in visual cortex and predict sensory attenuation at the perceptual level
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