Post-switching beta synchronization reveals concomitant sensory reafferences and active inhibition processes

Abstract

It is known that post-movement beta synchronization (PMBS) is involved both in active inhibition and in sensory reafferences processes. The aim of this study was examine the temporal and spatial dynamics of the PMBS involved during multi-limb coordination task. We investigated post-switching beta synchronization (assigned PMBS) using time-frequency and source estimations analyzes. Participants (n=17) initiated an auditory-paced bimanual tapping. After a 1500ms preparatory period, an imperative stimulus required to either selectively stop the left while maintaining the right unimanual tapping (Switch condition: SWIT) or to continue the bimanual tapping (Continue condition: CONT). PMBS significantly increased in SWIT compared to CONT with maximal difference within right central region in broad-band 14–30Hz and within left central region in restricted-band 22–26Hz. Source estimations localized these effects within right pre-frontal cortex and left parietal cortex, respectively. A negative correlation showed that participants with a low percentage of errors in SWIT had a large PMBS amplitude within right parietal and frontal cortices. This study shows for the first time simultaneous PMBS with distinct functions in different brain regions and frequency ranges. The left parietal PMBS restricted to 22–26Hz could reflect the sensory reafferences of the right hand tapping disrupted by the switching. In contrast, the right pre-frontal PMBS in a broad-band 14–30Hz is likely reflecting the active inhibition of the left hand stopped. Finally, correlations between behavioral performance and the magnitude of the PMBS suggest that beta oscillations can be viewed as a marker of successful active inhibition.