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Jan Vesper

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7 papers
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7

YNICL Journal 2025 Journal Article

Longitudinal changes of resting-state networks in Parkinson‘s disease

  • Matthias Sure
  • Rasha Hyder
  • Levent Kandemir
  • Jan Vesper
  • Alfons Schnitzler
  • Esther Florin

Deep brain stimulation (DBS), but also the sole implantation of the electrodes and dopaminergic medication, can reduce symptoms in Parkinson's disease (PD) patients. Furthermore, an effect on network activity is known for all three options separately. However, long-term effects have rarely been investigated. Therefore, in the present study, we focus on the long-term impact of dopaminergic medication on whole-brain network activity following DBS electrode implantation. Therefore, we extracted resting state networks (RSNs) of 20 PD patients (4 females, (59.00 ± 9.72 years) from magnetoencephalography data. We recorded 30 min of resting-state activity two days before and one year after implantation of the electrodes with and without dopaminergic medication, but DBS was turned off. RSNs were obtained based on the phase-amplitude coupling between a low-frequency phase and a high gamma amplitude and examined for differences between conditions (i.e., pre- vs. post-surgery). We identified three RSNs across all conditions: sensory-motor, visual, and frontal. Each RSN was selectively altered due to a year of disease progression - while patients being treated with dopaminergic medication and DBS. In line with previous literature, we focus on longitudinal changes in RSNs over time after electrode implantation, acknowledging that chronic DBS treatment and other factors may confound the interpretation of these changes. In addition, the alterations found were RSN specific, as dopaminergic medication showed a greater impact on the frontal RSN, and the longitudinal factor expressed by the disease progression was more severe in alterations in the SMN and the visual RSN.

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YNICL Journal 2025 Journal Article

Modulations of thalamo-cortical coupling during voluntary movement in patients with essential tremor

  • Alexandra Steina
  • Sarah Sure
  • Markus Butz
  • Jan Vesper
  • Alfons Schnitzler
  • Jan Hirschmann

The ventral intermediate nucleus of the thalamus (VIM) is the main thalamic hub for cerebellar inputs and the primary deep brain stimulation target in essential tremor (ET). As such, it presumably plays a critical role in motor control. However, this structure is rarely studied in humans, and existing studies mostly focus on tremor. Here, we studied neural oscillations in the VIM and their coupling to cortical oscillations during voluntary movement. We investigated thalamo-cortical coupling, combining recordings of thalamic local field potentials and magnetoencephalography, in 10 ET patients with externalized deep brain stimulation electrodes. During the recording, patients repeatedly pressed a button in response to a visual cue. In a whole-brain analysis of VIM-cortex coherence, we contrasted activity during pre-movement baseline and button pressing. Button pressing was associated with a bilateral decrease of thalamic alpha (8-12 Hz) and beta (13-21 Hz) power and a contralateral gamma (35-90 Hz) power increase. Alpha/low-beta (8-20 Hz) coherence decreased during movement. This effect localized to the supplementary motor area and premotor cortex. A high-beta (21-35 Hz) coherence increase occurred in the same region but was more focal than the suppression. Pre-movement levels of thalamo-cortex low-beta coherence correlated with reaction time. Our results demonstrate that voluntary movement is associated with modulations of behaviourally relevant thalamic coupling, primarily to premotor areas. We observed a clear distinction between low- and high-beta frequencies and our results suggest that the concept of "antikinetic" beta oscillations, originating from research on Parkinson's disease, is transferable to ET.

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YNICL Journal 2023 Journal Article

Alterations of resting-state networks of Parkinson‘s disease patients after subthalamic DBS surgery

  • Matthias Sure
  • Sean Mertiens
  • Jan Vesper
  • Alfons Schnitzler
  • Esther Florin

The implantation of deep brain stimulation (DBS) electrodes in Parkinson's disease (PD) patients can lead to a temporary improvement in motor symptoms, known as the stun effect. However, the network alterations induced by the stun effect are not well characterized. As therapeutic DBS is known to alter resting-state networks (RSN) and subsequent motor symptoms in patients with PD, we aimed to investigate whether the DBS-related stun effect also modulated RSNs. Therefore, we analyzed RSNs of 27 PD patients (8 females, 59.0 +- 8.7 years) using magnetoencephalography and compared them to RSNs of 24 age-matched healthy controls (8 females, 62.8 +- 5.1 years). We recorded 30 min of resting-state activity two days before and one day after implantation of the electrodes with and without dopaminergic medication. RSNs were determined by use of phase-amplitude coupling between a low frequency phase and a high gamma amplitude and examined for differences between conditions (i.e., pre vs post surgery). We identified four RSNs across all conditions: sensory-motor, visual, fronto-occipital, and frontal. Each RSN was altered due to electrode implantation. Importantly, these changes were not restricted to spatially close areas to the electrode trajectory. Interestingly, pre-operative RSNs corresponded better with healthy control RSNs regarding the spatial overlap, although the stun effect is associated with motor improvement. Our findings reveal that the stun effect induced by implantation of electrodes exerts brain wide changes in different functional RSNs.

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YNICL Journal 2023 Journal Article

Neuroimaging-based analysis of DBS outcomes in pediatric dystonia: Insights from the GEPESTIM registry

  • Bassam Al-Fatly
  • Sabina J. Giesler
  • Simon Oxenford
  • Ningfei Li
  • Till A. Dembek
  • Johannes Achtzehn
  • Patricia Krause
  • Veerle Visser-Vandewalle

INTRODUCTION: Deep brain stimulation (DBS) is an established treatment in patients of various ages with pharmaco-resistant neurological disorders. Surgical targeting and postoperative programming of DBS depend on the spatial location of the stimulating electrodes in relation to the surrounding anatomical structures, and on electrode connectivity to a specific distribution pattern within brain networks. Such information is usually collected using group-level analysis, which relies on the availability of normative imaging resources (atlases and connectomes). Analysis of DBS data in children with debilitating neurological disorders such as dystonia would benefit from such resources, especially given the developmental differences in neuroimaging data between adults and children. We assembled pediatric normative neuroimaging resources from open-access datasets in order to comply with age-related anatomical and functional differences in pediatric DBS populations. We illustrated their utility in a cohort of children with dystonia treated with pallidal DBS. We aimed to derive a local pallidal sweetspot and explore a connectivity fingerprint associated with pallidal stimulation to exemplify the utility of the assembled imaging resources. METHODS: An average pediatric brain template (the MNI brain template 4.5-18.5 years) was implemented and used to localize the DBS electrodes in 20 patients from the GEPESTIM registry cohort. A pediatric subcortical atlas, analogous to the DISTAL atlas known in DBS research, was also employed to highlight the anatomical structures of interest. A local pallidal sweetspot was modeled, and its degree of overlap with stimulation volumes was calculated as a correlate of individual clinical outcomes. Additionally, a pediatric functional connectome of 100 neurotypical subjects from the Consortium for Reliability and Reproducibility was built to allow network-based analyses and decipher a connectivity fingerprint responsible for the clinical improvements in our cohort. RESULTS: We successfully implemented a pediatric neuroimaging dataset that will be made available for public use as a tool for DBS analyses. Overlap of stimulation volumes with the identified DBS-sweetspot model correlated significantly with improvement on a local spatial level (R = 0.46, permuted p = 0.019). The functional connectivity fingerprint of DBS outcomes was determined to be a network correlate of therapeutic pallidal stimulation in children with dystonia (R = 0.30, permuted p = 0.003). CONCLUSIONS: Local sweetspot and distributed network models provide neuroanatomical substrates for DBS-associated clinical outcomes in dystonia using pediatric neuroimaging surrogate data. Implementation of this pediatric neuroimaging dataset might help to improve the practice and pave the road towards a personalized DBS-neuroimaging analyses in pediatric patients.

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YNIMG Journal 2022 Journal Article

Cortical network formation based on subthalamic beta bursts in Parkinson's disease

  • Matthias Sure
  • Jan Vesper
  • Alfons Schnitzler
  • Esther Florin

Recent evidence suggests that beta bursts in subthalamic nucleus (STN) play an important role in Parkinsonian pathophysiology. We studied the spatio-temporal relationship between STN beta bursts and cortical activity in 26 Parkinson's disease (PD) patients undergoing deep brain stimulation (DBS) surgery. Postoperatively, we simultaneously recorded STN local field potentials (LFP) from externalized DBS leads and cortical activity using whole-brain magnetoencephalography. Event-related magnetic fields (ERF) were averaged time-locked to STN beta bursts and subjected to source localization. Our results demonstrate that ERF exhibiting activity significantly different from baseline activity were localized within areas functionally related to associative, limbic, and motor systems as well as regions pertinent for visual and language processing. Our data suggest that STN beta bursts are involved in network formation between STN and cortex. This interaction is in line with the idea of parallel processing within the basal ganglia-cortex loop, specifically within the functional subsystems of the STN (i.e., associative, limbic, motor, and the related cortical areas). ERFs within visual and language-related cortical areas indicate involvement of beta bursts in STN-cortex networks beyond the associative, limbic, and motor loops. In sum, our results highlight the involvement of STN beta bursts in the formation of multiple STN - cortex loops in patients with PD.

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