Schoenfeld, M. J. | Search bioRxiv

bioRxiv2025

Modulation of temporal prediction by STN-DBS in Parkinson's disease: Links between behavior and cortical oscillations

BACKGROUNDAccurate temporal prediction is essential for adaptive behavior and relies on coordinated neural activity within cortico-basal ganglia circuits. Parkinsons disease (PD), with the main hallmark of dopaminergic depletion and abnormal neural synchrony, impairs this ability. Deep brain stimulation deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a widely used treatment for reducing motor symptoms in PD, but its effects on temporal prediction remain not fully understood. OBJECTIVESThis study aimed to investigate how STN-DBS influences temporal prediction performance and its underlying oscillatory dynamics in PD patients, with a particular focus on beta-band power and delta-band inter-trial phase consistency (ITPC). METHODS13 PD patients (5 female, age: 64 {+/-} 5.7 years; disease duration: 11.8 {+/-} 1.8 years) with STN-DBS performed a temporal prediction task with (DBS ON) and without (DBS OFF) stimulation, while 64-channel-electroencephalography (EEG) was recorded. 20 age-matched healthy controls completed the same task. Behavioral performance was assessed using psychometric function slopes. Time-frequency analyses and source-level EEG measures examined beta power and delta ITPC. RESULTSPD patients showed impaired temporal prediction performance compared to controls, reflected in shallower psychometric slopes. DBS significantly improved performance to a level comparable to those of controls. EEG revealed reduced beta suppression in PD patients during DBS OFF, while beta suppression in DBS ON was comparable to controls. Both DBS OFF and ON exhibited reduced delta ITPC compared to controls. In DBS ON, source-level delta ITPC was positively correlated with temporal prediction accuracy. CONCLUSIONSTN-DBS improves temporal prediction performance in PD, likely through modulation of beta and delta oscillatory activity. While beta power suppression is partially restored, deficits in delta phase alignment persist, suggesting frequency-specific DBS effects on temporal prediction processes.

neuroscience↗

bioRxiv2024

Differential beta and gamma activity modulation during unimanual and bimanual motor learning

Movement-related dynamics in the beta and gamma bands have been studied in relation to motor execution and learning during unimanual movements, but their roles in complex bimanual tasks remain largely unexplored. This study aimed to investigate how beta and gamma activity differs between unimanual and bimanual movements, and how these neural signatures evolve during the learning process. Our motor task incorporated varying levels of bimanual interaction: unimanual, bimanual-equal, and bimanual-unequal. Magnetoencephalography data were recorded during task performance, and beta and gamma dynamics were quantified. As expected, increasing task complexity from unimanual to bimanual-equal, and then to bimanual-unequal movements resulted in slower and less accurate performance. Across all conditions, significant beta event-related desynchronization (ERD) and gamma event-related synchronization (ERS) were observed during movement, as well as beta ERS after movement. Bimanual movements exhibited greater beta ERD, beta ERS, and gamma ERS compared to unimanual movements. With practice, participants demonstrated faster and more accurate movements, accompanied by enhanced beta ERS responses. Furthermore, learning-related reductions in errors correlated with increases in beta ERS. These findings suggest the distinct behavioural and neural demands of unimanual versus bimanual movements and highlight the important role of beta dynamics in motor performance and learning.

physiology↗