Biology subjects

Pedrosa, D. J.

Publications and source records attributed to Pedrosa, D. J..

3 recordsLinked to original sources

bioRxiv2025

Characterizing the frequency-specific and spatiotemporal dynamics of β-γ Phase-Amplitude Coupling in Parkinson's disease

Cross-frequency coupling (CFC) has been proposed to facilitate neural information transfer across spatial and temporal scales. Phase-amplitude coupling (PAC), a type of CFC in which the amplitude of a faster brain oscillation is coupled to the phase of a slower brain oscillation, is implicated in various higher-order cognitive functions and was shown to be pathologically altered in neurological and psychiatric disease. In Parkinsons disease (PD), the coupling between gamma amplitude (50-150 Hz) to beta phase (13-35 Hz) is exaggerated. Enhanced {beta}-{gamma} PAC was found in the subthalamic nucleus and various cortical sources and shown to be responsive to dopaminergic therapy and deep brain stimulation (DBS). Therefore, exaggerated {beta}-{gamma} PAC has been proposed to be a disease marker and a potential target for brain circuit interventions. Despite these promising findings, a significant knowledge gap remains, as the spatial and frequency-specific dynamics of {beta}-{gamma} PAC and its association with motor symptoms and therapy remain elusive. To address this knowledge gap, we employed high-density electroencephalography (EEG) with advanced source localisation techniques for PD patients at rest. We highlight three key findings: (1) a frequency-specific increase in high {beta} (23-35 Hz)-{gamma} PAC within and between sources of the cortical motor network, (2) a link between elevated high {beta}-{gamma} PAC and bradykinesia and rigidity when OFF medication, but not tremor, and (3) a medication-induced reduction in high {beta}-{gamma} PAC in the supplementary motor area correlating with clinical improvement. Altogether, this study provides novel insights into the pathophysiology of PD as an oscillopathy and identifies high {beta}-{gamma} PAC as a potential marker of Parkinsonian symptoms and treatment effects. This has important implications for invasive as well as non-invasive therapeutic strategies as high {beta}-{gamma} PAC targeting might hold greater promise than targeting {beta}-{gamma} PAC per se.

neuroscience↗

bioRxiv2022

High-and Low-Frequency Deep Brain Stimulation in the Subthalamic Nucleus differentially modulate Response Inhibition and Action Selection in Parkinson's Disease

BackgroundWhile deep brain stimulation (DBS) in the subthalamic nucleus (STN) improves motor functions in Parkinsons disease (PD), it has also been associated with increased impulsivity. MethodsA combined approach of eye-tracking and high-density EEG was used to investigate how high- and low-frequency DBS impact impulsive actions in the antisaccade task in a cohort of ten persons with PD. Computational modelling of the behavioral outcomes allowed a nuanced insight into the effect of DBS on response inhibition and action selection processes. Results: Against our expectations, both 130 Hz- and 60 Hz-DBS improved response inhibition as both resulted in a reduced rate of early reflexive errors. Correspondingly, DBS with both frequencies led to increased desynchronization of beta power during the preparatory period which may be a correlate of anticipatory activation in the oculomotor network. Low-frequency DBS additionally was associated with increased midfrontal theta power, an established marker of cognitive control. While higher midfrontal theta power predicted longer antisaccade latencies in off-DBS state on a trial-by-trial basis, 130 Hz-DBS reversed this relationship. As informed by the computational model, 130 Hz-DBS further led to a shift in the speed-accuracy trade-off causing an acceleration and error-proneness of actions later in the trial. ConclusionsOur results disentangle the impact of DBS on early and late impulsive actions. Only 130 Hz-DBS may disrupt theta-mediated cognitive control mechanisms via medial frontal - STN pathways that are involved in delaying action selection. 60 Hz-DBS may provide beneficial effects on response inhibition without the detrimental effect on action selection seen with 130 Hz-DBS. FundingThis study was supported by the SUCCESS program of Philipps-University Marburg (JW), the Hessian Ministry of Sciences and the Arts, clusterproject: The Adaptive Mind - TAM (FB / AK) and the German Research Foundation (DFG). International Research Training Group 1901 (FB / AK)

neuroscience↗

bioRxiv2018

Decoding voluntary movements and postural tremor based on thalamic LFPs for closed-loop stimulation for essential tremor

High frequency deep brain stimulation (DBS) targeting motor thalamus is an effective therapy for essential tremor (ET). However, conventional continuous stimulation may deliver unnecessary current to the brain since tremor mainly affects voluntary movements and sustained postures in ET. We recorded LFPs from the motor thalamus, surface electromyographic (EMG) signals and/or behavioural measurements in seven ET patients during temporary lead externalization after the first surgery for DBS when they performed different voluntary upper limb movements and in nine more patients during the surgery, when they were asked to lift their arms to trigger postural tremor. We show that both voluntary movements and postural tremor can be decoded based on features extracted from thalamic LFPs using a machine learning based binary classifier. This information can be used to close the loop for DBS so that stimulation could be delivered on demand, without the need for peripheral sensors or additional invasive electrodes.

neuroscience↗