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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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Jafadideh AT, Asl BM. Modified Dominant Mode Rejection Beamformer for Localizing Brain Activities When Data Covariance Matrix Is Rank Deficient. IEEE Trans Biomed Eng 2018; 66:2241-2252. [PMID: 30561337 DOI: 10.1109/tbme.2018.2886251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Minimum variance beamformer (MVB) and its extensions fail in localizing short time brain activities particularly evoked potentials because of rank deficiency or inaccurate estimation of a data covariance matrix. In this paper, the conventional dominant mode rejection (DMR) adaptive beamformer is modified to localize brain short time activities. METHODS In the modified DMR, it is attempted to obtain a well-conditioned covariance matrix by dividing the eigenvalues of the data covariance matrix into dominant, medium, and small eigenvalues and then modifying medium and small parts. The performance of the proposed approach is compared with diagonal loading MVB (DL_MVB) and fast fully adaptive (FFA) beamformer by using simulated event-related potentials and real event-related field data. Eigenspace versions of DL_MVB and modified DMR are also implemented. RESULTS In all simulations, the modified DMR obtains the least localization error (0-5 mm) and spread radius (0-8 mm) when the signal-to-noise ratio (SNR) varies from 0 to 10 dB with step 1 dB. In real data, the new approach in comparison to two other ones attains the most concentrated power spectrum. Eigenspace projection of DL_MVB presents better results than DL_MVB but worse results than the modified DMR. Applying eigenspace projection on the proposed method improves its performance at high SNR levels. CONCLUSION Empirical results illustrate the superiority of the proposed DMR method to the DL_MVB and FFA in localizing brain short time activities. SIGNIFICANCE The proposed method can be utilized in source localization of epilepsy for presurgical clinical evaluation purpose and also in applications dealing with the localization of evoked potentials and fields.
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Ranzi P, Freund JA, Thiel CM, Herrmann CS. Encephalography Connectivity on Sources in Male Nonsmokers after Nicotine Administration during the Resting State. Neuropsychobiology 2017; 74:48-59. [PMID: 27802427 DOI: 10.1159/000450711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 09/09/2016] [Indexed: 11/19/2022]
Abstract
We present an encephalography (EEG) connectivity study where 30 healthy male nonsmokers were randomly allocated either to a nicotine group (14 subjects, 7 mg of transdermal nicotine) or to a placebo group. EEG activity was recorded in an eyes-open (EO) and eyes-closed (EC) condition before and after drug administration. This is a reanalysis of a previous dataset. Through a source reconstruction procedure, we extracted 13 time series representing 13 sources belonging to a resting-state network. Here, we conducted connectivity analysis (renormalized partial directed coherence; rPDC) on sources, focusing on the frequency range of 8.5-18.4 Hz, subdivided into 3 frequency bands (α1, α2, and β1) with the hypothesis that an increase in vigilance would modulate connectivity. Furthermore, a phase-amplitude coupling (mean resultant vector length; VL) analysis, was performed investigating whether an increase of vigilance would modulate phase-amplitude coupling. In the VL analysis we estimated the coupling of the phases of 3 low frequencies (α1, α2, and β1), respectively, with the amplitude of high-frequency oscillations (30-40 Hz, low γ). With rPDC we found that during the EC condition, nicotine decreased feedback connectivity (from the precentral gyrus to precuneus, angular gyrus, cuneus and superior occipital gyrus) at 10.5-12.4 Hz. The VL analysis showed nicotine-induced increases in coupling at 10.5-18.4 Hz in the precuneus, cuneus and superior occipital gyrus during the EC condition. During the EO condition, no significant results were found in connectivity or phase-amplitude coupling measures at any frequency range. In conclusion, the results suggest that nicotine potentially increases the level of vigilance in the EC condition.
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Affiliation(s)
- Paolo Ranzi
- Experimental Psychology Group, Department of Psychology, Cluster of Excellence 'Hearing4all', European Medical School, Carl von Ossietzky University, Oldenburg, Germany
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Sitaram R, Ros T, Stoeckel L, Haller S, Scharnowski F, Lewis-Peacock J, Weiskopf N, Blefari ML, Rana M, Oblak E, Birbaumer N, Sulzer J. Closed-loop brain training: the science of neurofeedback. Nat Rev Neurosci 2016; 18:86-100. [PMID: 28003656 DOI: 10.1038/nrn.2016.164] [Citation(s) in RCA: 527] [Impact Index Per Article: 65.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Oswal A, Beudel M, Zrinzo L, Limousin P, Hariz M, Foltynie T, Litvak V, Brown P. Deep brain stimulation modulates synchrony within spatially and spectrally distinct resting state networks in Parkinson's disease. Brain 2016; 139:1482-96. [PMID: 27017189 PMCID: PMC4845255 DOI: 10.1093/brain/aww048] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/25/2016] [Indexed: 11/13/2022] Open
Abstract
Chronic dopamine depletion in Parkinson's disease leads to progressive motor and cognitive impairment, which is associated with the emergence of characteristic patterns of synchronous oscillatory activity within cortico-basal-ganglia circuits. Deep brain stimulation of the subthalamic nucleus is an effective treatment for Parkinson's disease, but its influence on synchronous activity in cortico-basal-ganglia loops remains to be fully characterized. Here, we demonstrate that deep brain stimulation selectively suppresses certain spatially and spectrally segregated resting state subthalamic nucleus-cortical networks. To this end we used a validated and novel approach for performing simultaneous recordings of the subthalamic nucleus and cortex using magnetoencephalography (during concurrent subthalamic nucleus deep brain stimulation). Our results highlight that clinically effective subthalamic nucleus deep brain stimulation suppresses synchrony locally within the subthalamic nucleus in the low beta oscillatory range and furthermore that the degree of this suppression correlates with clinical motor improvement. Moreover, deep brain stimulation relatively selectively suppressed synchronization of activity between the subthalamic nucleus and mesial premotor regions, including the supplementary motor areas. These mesial premotor regions were predominantly coupled to the subthalamic nucleus in the high beta frequency range, but the degree of deep brain stimulation-associated suppression in their coupling to the subthalamic nucleus was not found to correlate with motor improvement. Beta band coupling between the subthalamic nucleus and lateral motor areas was not influenced by deep brain stimulation. Motor cortical coupling with subthalamic nucleus predominantly involved driving of the subthalamic nucleus, with those drives in the higher beta frequency band having much shorter net delays to subthalamic nucleus than those in the lower beta band. These observations raise the possibility that cortical connectivity with the subthalamic nucleus in the high and low beta bands may reflect coupling mediated predominantly by the hyperdirect and indirect pathways to subthalamic nucleus, respectively, and that subthalamic nucleus deep brain stimulation predominantly suppresses the former. Yet only the change in strength of local subthalamic nucleus oscillations correlates with the degree of improvement during deep brain stimulation, compatible with the current view that a strengthened hyperdirect pathway is a prerequisite for locally generated beta activity but that it is the severity of the latter that may determine or index motor impairment.
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Affiliation(s)
- Ashwini Oswal
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK Medical Research Council Brain Network Dynamics Unit, University of Oxford, UK Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, 12 Queen Square, London, UK
| | - Martijn Beudel
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London, UK University Medical Centre Groningen, Department of Neurology, University of Groningen, The Netherlands
| | - Ludvic Zrinzo
- Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London, UK
| | - Patricia Limousin
- Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London, UK
| | - Marwan Hariz
- Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London, UK
| | - Tom Foltynie
- Unit of Functional Neurosurgery, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, Queen Square, London, UK
| | - Vladimir Litvak
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, 12 Queen Square, London, UK
| | - Peter Brown
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK Medical Research Council Brain Network Dynamics Unit, University of Oxford, UK
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Oswal A, Jha A, Neal S, Reid A, Bradbury D, Aston P, Limousin P, Foltynie T, Zrinzo L, Brown P, Litvak V. Analysis of simultaneous MEG and intracranial LFP recordings during Deep Brain Stimulation: a protocol and experimental validation. J Neurosci Methods 2015; 261:29-46. [PMID: 26698227 PMCID: PMC4758829 DOI: 10.1016/j.jneumeth.2015.11.029] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 11/30/2015] [Indexed: 11/17/2022]
Abstract
Setup for MEG and intracranial recordings during Deep Brain Stimulation is described. Phantom experiment showed correct recovery of oscillatory sources despite artefacts. The method is applied to real data from a patient with Parkinson's Disease. Cortico-subthalamic coherence profiles on and off stimulation were comparable.
Background Deep Brain Stimulation (DBS) is an effective treatment for several neurological and psychiatric disorders. In order to gain insights into the therapeutic mechanisms of DBS and to advance future therapies a better understanding of the effects of DBS on large-scale brain networks is required. New method In this paper, we describe an experimental protocol and analysis pipeline for simultaneously performing DBS and intracranial local field potential (LFP) recordings at a target brain region during concurrent magnetoencephalography (MEG) measurement. Firstly we describe a phantom setup that allowed us to precisely characterise the MEG artefacts that occurred during DBS at clinical settings. Results Using the phantom recordings we demonstrate that with MEG beamforming it is possible to recover oscillatory activity synchronised to a reference channel, despite the presence of high amplitude artefacts evoked by DBS. Finally, we highlight the applicability of these methods by illustrating in a single patient with Parkinson's disease (PD), that changes in cortical-subthalamic nucleus coupling can be induced by DBS. Comparison with existing approaches To our knowledge this paper provides the first technical description of a recording and analysis pipeline for combining simultaneous cortical recordings using MEG, with intracranial LFP recordings of a target brain nucleus during DBS.
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Affiliation(s)
- Ashwini Oswal
- Wellcome Trust Centre for Neuroimaging, 12 Queen Square, London, UK; Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
| | - Ashwani Jha
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, Queen Square, London, UK
| | - Spencer Neal
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, Queen Square, London, UK
| | - Alphonso Reid
- Wellcome Trust Centre for Neuroimaging, 12 Queen Square, London, UK
| | - David Bradbury
- Wellcome Trust Centre for Neuroimaging, 12 Queen Square, London, UK
| | - Peter Aston
- Wellcome Trust Centre for Neuroimaging, 12 Queen Square, London, UK
| | - Patricia Limousin
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, Queen Square, London, UK
| | - Tom Foltynie
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, Queen Square, London, UK
| | - Ludvic Zrinzo
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, Queen Square, London, UK
| | - Peter Brown
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
| | - Vladimir Litvak
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK.
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