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Session: NeuroMuscular
Session starts: Thursday 26 January, 14:30
Presentation starts: 15:30
Room: Room 530

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Janne Heijs ()
Silvana Huertas-Penen ()
Bettina Schwab ()
Richard van Wezel ()
Tjitske Heida ()

Abstract:
Sensorimotor synchronization (SMS) involves the adaptation of voluntary movements to external, rhythmic, sensory stimuli, called cues. SMS can, for instance, be used to investigate the timing mechanisms of voluntary movements. Voluntary movements are characterized by event-related desynchronization (ERD) of the sensorimotor cortex during movement execution (cortical activity), followed by event-related synchronization (ERS) after movement termination (cortical inactivity). Little is known about the effect of cue characteristics on the oscillatory activity (ERD/ERS) during SMS. Therefore, the aim of this study is to evaluate the cortical activity related to SMS guided by different types of external sensory cues, to assess the effect of type, frequency and rhythmicity of cues. Twenty healthy subjects performed a finger tapping experiment, following different sensory cues in a 2x2x2-design, to evaluate the effect of: 1) cueing type: visual (flickering circle) vs. auditory cues (repetitive tones); 2) cueing frequency: 1Hz (discrete) vs. 3.2Hz cues (continuous); and 3) cueing rhythmicity: isorhythmic (one rhythm) vs. polyrhythmic cues (two rhythms in a [2:3]-relationship). A 32-channel EEG system recorded the electrocortical activity. ERD/ERS of the α-band (8-12Hz) and β-band (12-30Hz) was evaluated around finger tap (FT). Summary of the results: 1) The cueing frequency affected oscillatory activity in central and parietal electrodes. With 1Hz cues, β-ERD during FT was followed by β-ERS after FT, while 3.2Hz cues showed a sustained β-ERD. 2) Small differences in oscillatory activity were observed between cueing types. With 1Hz-isorhythmic cues, β-ERS after FT was stronger in central electrodes for auditory cues, but more widespread towards parietal electrodes for visual cues. Moreover, α-ERS during FT was stronger for visual cues. 3) A strong effect of cueing rhythmicity was observed, especially for visual cues. Polyrhythmic cues caused a widespread increase in α- and β-ERD, while isorhythmic cues showed α-ERS in central and parietal electrodes. These results showed that the characteristics of the cue and the related movement affect the cortical oscillations during SMS in a finger tapping task, suggesting differences in movement execution, complexity or processing of the cues. Similar studies should be performed in patients with Parkinson’s disease, for whom cueing is a common therapy to improve gait.