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Borgheai SB, Opri E, Isbaine F, Cole E, Deligani RJ, Laxpati N, Risk BB, Willie JT, Gross RE, Yong NA, McIntyre CC, Miocinovic S. Neural pathway activation in the subthalamic region depends on stimulation polarity. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.01.24306044. [PMID: 38746250 PMCID: PMC11092741 DOI: 10.1101/2024.05.01.24306044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Deep brain stimulation (DBS) is an effective treatment for Parkinson's disease (PD); however, there is limited understanding of which subthalamic pathways are recruited in response to stimulation. Here, by focusing on the polarity of the stimulus waveform (cathodic vs. anodic), our goal was to elucidate biophysical mechanisms that underlie electrical stimulation in the human brain. In clinical studies, cathodic stimulation more easily triggers behavioral responses, but anodic DBS broadens the therapeutic window. This suggests that neural pathways involved respond preferentially depending on stimulus polarity. To experimentally compare the activation of therapeutically relevant pathways during cathodic and anodic subthalamic nucleus (STN) DBS, pathway activation was quantified by measuring evoked potentials resulting from antidromic or orthodromic activation in 15 PD patients undergoing DBS implantation. Cortical evoked potentials (cEP) were recorded using subdural electrocorticography, DBS local evoked potentials (DLEP) were recorded from non-stimulating contacts and EMG activity was recorded from arm and face muscles. We measured: 1) the amplitude of short-latency cEP, previously demonstrated to reflect activation of the cortico-STN hyperdirect pathway, 2) DLEP amplitude thought to reflect activation of STN-globus pallidus (GP) pathway, and 3) amplitudes of very short-latency cEP and motor evoked potentials (mEP) for activation of cortico-spinal/bulbar tract (CSBT). We constructed recruitment and strength-duration curves for each EP/pathway to compare the excitability for different stimulation polarities. We compared experimental data with the most advanced DBS computational models. Our results provide experimental evidence that subcortical cathodic and anodic stimulation activate the same pathways in the STN region and that cathodic stimulation is in general more efficient. However, relative efficiency varies for different pathways so that anodic stimulation is the least efficient in activating CSBT, more efficient in activating the HDP and as efficient as cathodic in activating STN-GP pathway. Our experiments confirm biophysical model predictions regarding neural activations in the central nervous system and provide evidence that stimulus polarity has differential effects on passing axons, terminal synapses, and local neurons. Comparison of experimental results with clinical DBS studies provides further evidence that the hyperdirect pathway may be involved in the therapeutic mechanisms of DBS.
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Spooner RK, Hizli BJ, Bahners BH, Schnitzler A, Florin E. Modulation of DBS-induced cortical responses and movement by the directionality and magnitude of current administered. NPJ Parkinsons Dis 2024; 10:53. [PMID: 38459031 PMCID: PMC10923868 DOI: 10.1038/s41531-024-00663-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 02/16/2024] [Indexed: 03/10/2024] Open
Abstract
Subthalamic deep brain stimulation (STN-DBS) is an effective therapy for alleviating motor symptoms in people with Parkinson's disease (PwP), although some may not receive optimal clinical benefits. One potential mechanism of STN-DBS involves antidromic activation of the hyperdirect pathway (HDP), thus suppressing cortical beta synchrony to improve motor function, albeit the precise mechanisms underlying optimal DBS parameters are not well understood. To address this, 18 PwP with STN-DBS completed a 2 Hz monopolar stimulation of the left STN during MEG. MEG data were imaged in the time-frequency domain using minimum norm estimation. Peak vertex time series data were extracted to interrogate the directional specificity and magnitude of DBS current on evoked and induced cortical responses and accelerometer metrics of finger tapping using linear mixed-effects models and mediation analyses. We observed increases in evoked responses (HDP ~ 3-10 ms) and synchronization of beta oscillatory power (14-30 Hz, 10-100 ms) following DBS pulse onset in the primary sensorimotor cortex (SM1), supplementary motor area (SMA) and middle frontal gyrus (MFG) ipsilateral to the site of stimulation. DBS parameters significantly modulated neural and behavioral outcomes, with clinically effective contacts eliciting significant increases in medium-latency evoked responses, reductions in induced SM1 beta power, and better movement profiles compared to suboptimal contacts, often regardless of the magnitude of current applied. Finally, HDP-related improvements in motor function were mediated by the degree of SM1 beta suppression in a setting-dependent manner. Together, these data suggest that DBS-evoked brain-behavior dynamics are influenced by the level of beta power in key hubs of the basal ganglia-cortical loop, and this effect is exacerbated by the clinical efficacy of DBS parameters. Such data provides novel mechanistic and clinical insight, which may prove useful for characterizing DBS programming strategies to optimize motor symptom improvement in the future.
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Affiliation(s)
- Rachel K Spooner
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany.
| | - Baccara J Hizli
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Bahne H Bahners
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
- Department of Neurology, Center for Movement Disorders and Neuromodulation, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
- Department of Neurology, Center for Movement Disorders and Neuromodulation, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Esther Florin
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany.
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Spooner RK, Bahners BH, Schnitzler A, Florin E. Time-resolved quantification of fine hand movements as a proxy for evaluating bradykinesia-induced motor dysfunction. Sci Rep 2024; 14:5340. [PMID: 38438484 PMCID: PMC10912452 DOI: 10.1038/s41598-024-55862-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 02/28/2024] [Indexed: 03/06/2024] Open
Abstract
Bradykinesia is a behavioral manifestation that contributes to functional dependencies in later life. However, the current state of bradykinesia indexing primarily relies on subjective, time-averaged categorizations of motor deficits, which often yield poor reliability. Herein, we used time-resolved analyses of accelerometer recordings during standardized movements, data-driven factor analyses, and linear mixed effects models (LMEs) to quantitatively characterize general, task- and therapy-specific indices of motor impairment in people with Parkinson's disease (PwP) currently undergoing treatment for bradykinesia. Our results demonstrate that single-trial, accelerometer-based features of finger-tapping and rotational hand movements were significantly modulated by divergent therapeutic regimens. Further, these features corresponded well to current gold standards for symptom monitoring, with more precise predictive capacities of bradykinesia-specific declines achieved when considering kinematic features from diverse movement types together, rather than in isolation. Herein, we report data-driven, sample-specific kinematic profiles of diverse movement types along a continuous spectrum of motor impairment, which importantly, preserves the temporal scale for which biomechanical fluctuations in motor deficits evolve in humans. Therefore, this approach may prove useful for tracking bradykinesia-induced motor decline in aging populations the future.
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Affiliation(s)
- Rachel K Spooner
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany.
| | - Bahne H Bahners
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Alfons Schnitzler
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
- Department of Neurology, Center for Movement Disorders and Neuromodulation, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany
| | - Esther Florin
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany.
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Oswal A, Abdi‐Sargezeh B, Sharma A, Özkurt TE, Taulu S, Sarangmat N, Green AL, Litvak V. Spatiotemporal signal space separation for regions of interest: Application for extracting neuromagnetic responses evoked by deep brain stimulation. Hum Brain Mapp 2024; 45:e26602. [PMID: 38339906 PMCID: PMC10826894 DOI: 10.1002/hbm.26602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/18/2023] [Accepted: 01/08/2024] [Indexed: 02/12/2024] Open
Abstract
Magnetoencephalography (MEG) recordings are often contaminated by interference that can exceed the amplitude of physiological brain activity by several orders of magnitude. Furthermore, the activity of interference sources may spatially extend (known as source leakage) into the activity of brain signals of interest, resulting in source estimation inaccuracies. This problem is particularly apparent when using MEG to interrogate the effects of brain stimulation on large-scale cortical networks. In this technical report, we develop a novel denoising approach for suppressing the leakage of interference source activity into the activity representing a brain region of interest. This approach leverages spatial and temporal domain projectors for signal arising from prespecified anatomical regions of interest. We apply this denoising approach to reconstruct simulated evoked response topographies to deep brain stimulation (DBS) in a phantom recording. We highlight the advantages of our approach compared to the benchmark-spatiotemporal signal space separation-and show that it can more accurately reveal brain stimulation-evoked response topographies. Finally, we apply our method to MEG recordings from a single patient with Parkinson's disease, to reveal early cortical-evoked responses to DBS of the subthalamic nucleus.
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Affiliation(s)
- Ashwini Oswal
- MRC Brain Network Dynamics UnitUniversity of OxfordOxfordUK
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
- The Wellcome Centre for Human NeuroimagingUniversity College LondonLondonUK
- Department of NeurologyJohn Radcliffe HospitalOxfordUK
| | - Bahman Abdi‐Sargezeh
- MRC Brain Network Dynamics UnitUniversity of OxfordOxfordUK
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Abhinav Sharma
- MRC Brain Network Dynamics UnitUniversity of OxfordOxfordUK
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Tolga Esat Özkurt
- Graduate School of InformaticsMiddle East Technical UniversityAnkaraTurkey
| | - Samu Taulu
- Department of PhysicsUniversity of WashingtonSeattleWashingtonUSA
- Institute for Learning and Brain SciencesUniversity of WashingtonSeattleWashingtonUSA
| | | | - Alexander L. Green
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUK
| | - Vladimir Litvak
- The Wellcome Centre for Human NeuroimagingUniversity College LondonLondonUK
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Neumann WJ, Steiner LA, Milosevic L. Neurophysiological mechanisms of deep brain stimulation across spatiotemporal resolutions. Brain 2023; 146:4456-4468. [PMID: 37450573 PMCID: PMC10629774 DOI: 10.1093/brain/awad239] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/04/2023] [Accepted: 06/28/2023] [Indexed: 07/18/2023] Open
Abstract
Deep brain stimulation is a neuromodulatory treatment for managing the symptoms of Parkinson's disease and other neurological and psychiatric disorders. Electrodes are chronically implanted in disease-relevant brain regions and pulsatile electrical stimulation delivery is intended to restore neurocircuit function. However, the widespread interest in the application and expansion of this clinical therapy has preceded an overarching understanding of the neurocircuit alterations invoked by deep brain stimulation. Over the years, various forms of neurophysiological evidence have emerged which demonstrate changes to brain activity across spatiotemporal resolutions; from single neuron, to local field potential, to brain-wide cortical network effects. Though fruitful, such studies have often led to debate about a singular putative mechanism. In this Update we aim to produce an integrative account of complementary instead of mutually exclusive neurophysiological effects to derive a generalizable concept of the mechanisms of deep brain stimulation. In particular, we offer a critical review of the most common historical competing theories, an updated discussion on recent literature from animal and human neurophysiological studies, and a synthesis of synaptic and network effects of deep brain stimulation across scales of observation, including micro-, meso- and macroscale circuit alterations.
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Affiliation(s)
- Wolf-Julian Neumann
- Movement Disorder and Neuromodulation Unit, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin 10117, Germany
| | - Leon A Steiner
- Movement Disorder and Neuromodulation Unit, Department of Neurology, Charité - Universitätsmedizin Berlin, Berlin 10117, Germany
- Department of Clinical and Computational Neuroscience, Krembil Brain Institute, University Health Network, Toronto M5T 1M8, Canada
| | - Luka Milosevic
- Department of Clinical and Computational Neuroscience, Krembil Brain Institute, University Health Network, Toronto M5T 1M8, Canada
- Institute of Biomedical Engineering, Institute of Medical Sciences, and CRANIA Neuromodulation Institute, University of Toronto, Toronto M5S 3G9, Canada
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Campbell BA, Favi Bocca L, Tiefenbach J, Hogue O, Nagel SJ, Rammo R, Escobar Sanabria D, Machado AG, Baker KB. Myogenic and cortical evoked potentials vary as a function of stimulus pulse geometry delivered in the subthalamic nucleus of Parkinson's disease patients. Front Neurol 2023; 14:1216916. [PMID: 37693765 PMCID: PMC10484227 DOI: 10.3389/fneur.2023.1216916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/10/2023] [Indexed: 09/12/2023] Open
Abstract
Introduction The therapeutic efficacy of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson's disease (PD) may be limited for some patients by the presence of stimulation-related side effects. Such effects are most often attributed to electrical current spread beyond the target region. Prior computational modeling studies have suggested that changing the degree of asymmetry of the individual phases of the biphasic, stimulus pulse may allow for more selective activation of neural elements in the target region. To the extent that different neural elements contribute to the therapeutic vs. side-effect inducing effects of DBS, such improved selectivity may provide a new parameter for optimizing DBS to increase the therapeutic window. Methods We investigated the effect of six different pulse geometries on cortical and myogenic evoked potentials in eight patients with PD whose leads were temporarily externalized following STN DBS implant surgery. DBS-cortical evoked potentials were quantified using peak to peak measurements and wavelets and myogenic potentials were quantified using RMS. Results We found that the slope of the recruitment curves differed significantly as a function of pulse geometry for both the cortical- and myogenic responses. Notably, this effect was observed most frequently when stimulation was delivered using a monopolar, as opposed to a bipolar, configuration. Discussion Manipulating pulse geometry results in differential physiological effects at both the cortical and neuromuscular level. Exploiting these differences may help to expand DBS' therapeutic window and support the potential for incorporating pulse geometry as an additional parameter for optimizing therapeutic benefit.
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Affiliation(s)
- Brett A. Campbell
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Department of Neurosciences, Cleveland Clinic, Cleveland, OH, United States
| | - Leonardo Favi Bocca
- Center for Neurological Restoration, Cleveland Clinic, Cleveland, OH, United States
| | - Jakov Tiefenbach
- Department of Neurosciences, Cleveland Clinic, Cleveland, OH, United States
| | - Olivia Hogue
- Center for Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH, United States
| | - Sean J. Nagel
- Center for Neurological Restoration, Cleveland Clinic, Cleveland, OH, United States
- Department of Neurosurgery, Cleveland Clinic, Cleveland, OH, United States
| | - Richard Rammo
- Center for Neurological Restoration, Cleveland Clinic, Cleveland, OH, United States
- Department of Neurosurgery, Cleveland Clinic, Cleveland, OH, United States
| | - David Escobar Sanabria
- Center for Neurological Restoration, Cleveland Clinic, Cleveland, OH, United States
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, OH, United States
| | - Andre G. Machado
- Department of Neurosciences, Cleveland Clinic, Cleveland, OH, United States
- Center for Neurological Restoration, Cleveland Clinic, Cleveland, OH, United States
- Department of Neurosurgery, Cleveland Clinic, Cleveland, OH, United States
| | - Kenneth B. Baker
- Department of Neurosciences, Cleveland Clinic, Cleveland, OH, United States
- Center for Neurological Restoration, Cleveland Clinic, Cleveland, OH, United States
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