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Tang C, Todo Y, Kodera S, Sun R, Shimada A, Hirata A. A novel multivariate time series forecasting dendritic neuron model for COVID-19 pandemic transmission tendency. Neural Netw 2024; 179:106527. [PMID: 39029298 DOI: 10.1016/j.neunet.2024.106527] [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: 12/19/2022] [Revised: 02/21/2024] [Accepted: 07/07/2024] [Indexed: 07/21/2024]
Abstract
A novel coronavirus discovered in late 2019 (COVID-19) quickly spread into a global epidemic and, thankfully, was brought under control by 2022. Because of the virus's unknown mutations and the vaccine's waning potency, forecasting is still essential for resurgence prevention and medical resource management. Computational efficiency and long-term accuracy are two bottlenecks for national-level forecasting. This study develops a novel multivariate time series forecasting model, the densely connected highly flexible dendritic neuron model (DFDNM) to predict daily and weekly positive COVID-19 cases. DFDNM's high flexibility mechanism improves its capacity to deal with nonlinear challenges. The dense introduction of shortcut connections alleviates the vanishing and exploding gradient problems, encourages feature reuse, and improves feature extraction. To deal with the rapidly growing parameters, an improved variation of the adaptive moment estimation (AdamW) algorithm is employed as the learning algorithm for the DFDNM because of its strong optimization ability. The experimental results and statistical analysis conducted across three Japanese prefectures confirm the efficacy and feasibility of the DFDNM while outperforming various state-of-the-art machine learning models. To the best of our knowledge, the proposed DFDNM is the first to restructure the dendritic neuron model's neural architecture, demonstrating promising use in multivariate time series prediction. Because of its optimal performance, the DFDNM may serve as an important reference for national and regional government decision-makers aiming to optimize pandemic prevention and medical resource management. We also verify that DFDMN is efficiently applicable not only to COVID-19 transmission prediction, but also to more general multivariate prediction tasks. It leads us to believe that it might be applied as a promising prediction model in other fields.
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Affiliation(s)
- Cheng Tang
- Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, 819-0395, Japan; Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya-shi, 466-8555, Japan.
| | - Yuki Todo
- Faculty of Electrical and Computer Engineering, Kanazawa University, Kanazawa-shi, 920-1192, Japan
| | - Sachiko Kodera
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya-shi, 466-8555, Japan
| | - Rong Sun
- Faculty of Electrical and Computer Engineering, Kanazawa University, Kanazawa-shi, 920-1192, Japan; Division of Medical Oncology & Respiratory Medicine, Department of Internal Medicine, Faculty of Medicine, Shimane University, Izumo, Japan
| | - Atsushi Shimada
- Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, 819-0395, Japan
| | - Akimasa Hirata
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya-shi, 466-8555, Japan.
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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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Su TF, Hamilton JD, Guo Y, Potas JR, Shivdasani MN, Moalem-Taylor G, Fridman GY, Aplin FP. Peripheral direct current reduces naturally evoked nociceptive activity at the spinal cord in rodent models of pain. J Neural Eng 2024; 21:026044. [PMID: 38579742 DOI: 10.1088/1741-2552/ad3b6c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 04/05/2024] [Indexed: 04/07/2024]
Abstract
Objective.Electrical neuromodulation is an established non-pharmacological treatment for chronic pain. However, existing devices using pulsatile stimulation typically inhibit pain pathways indirectly and are not suitable for all types of chronic pain. Direct current (DC) stimulation is a recently developed technology which affects small-diameter fibres more strongly than pulsatile stimulation. Since nociceptors are predominantly small-diameter Aδand C fibres, we investigated if this property could be applied to preferentially reduce nociceptive signalling.Approach.We applied a DC waveform to the sciatic nerve in rats of both sexes and recorded multi-unit spinal activity evoked at the hindpaw using various natural stimuli corresponding to different sensory modalities rather than broad-spectrum electrical stimulus. To determine if DC neuromodulation is effective across different types of chronic pain, tests were performed in models of neuropathic and inflammatory pain.Main results.We found that in both pain models tested, DC application reduced responses evoked by noxious stimuli, as well as tactile-evoked responses which we suggest may be involved in allodynia. Different spinal activity of different modalities were reduced in naïve animals compared to the pain models, indicating that physiological changes such as those mediated by disease states could play a larger role than previously thought in determining neuromodulation outcomes.Significance.Our findings support the continued development of DC neuromodulation as a method for reduction of nociceptive signalling, and suggests that it may be effective at treating a broader range of aberrant pain conditions than existing devices.
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Affiliation(s)
- Tom F Su
- School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Jack D Hamilton
- School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Yiru Guo
- School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Jason R Potas
- School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
- Eccles Institute, John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Mohit N Shivdasani
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, New South Wales, Australia
| | - Gila Moalem-Taylor
- School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Gene Y Fridman
- Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University, Baltimore, MD, United States of America
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States of America
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, United States of America
| | - Felix P Aplin
- School of Biomedical Sciences, University of New South Wales, Sydney, New South Wales, Australia
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Kumaravelu K, Grill WM. Neural mechanisms of the temporal response of cortical neurons to intracortical microstimulation. Brain Stimul 2024; 17:365-381. [PMID: 38492885 PMCID: PMC11090107 DOI: 10.1016/j.brs.2024.03.012] [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: 10/12/2023] [Revised: 02/20/2024] [Accepted: 03/12/2024] [Indexed: 03/18/2024] Open
Abstract
BACKGROUND Intracortical microstimulation (ICMS) is used to map neuronal circuitry in the brain and restore lost sensory function, including vision, hearing, and somatosensation. The temporal response of cortical neurons to single pulse ICMS is remarkably stereotyped and comprises short latency excitation followed by prolonged inhibition and, in some cases, rebound excitation. However, the neural origin of the different response components to ICMS are poorly understood, and the interactions between the three response components during trains of ICMS pulses remains unclear. OBJECTIVE We used computational modeling to determine the mechanisms contributing to the temporal response to ICMS in model cortical neurons. METHODS We implemented a biophysically based computational model of a cortical column comprising neurons with realistic morphology and synapses and quantified the temporal response of cortical neurons to different ICMS protocols. We characterized the temporal responses to single pulse ICMS across stimulation intensities and inhibitory (GABA-B/GABA-A) synaptic strengths. To probe interactions between response components, we quantified the response to paired pulse ICMS at different inter-pulse intervals and the response to short trains at different stimulation frequencies. Finally, we evaluated the performance of biomimetic ICMS trains in evoking sustained neural responses. RESULTS Single pulse ICMS evoked short latency excitation followed by a period of inhibition, but model neurons did not exhibit post-inhibitory excitation. The strength of short latency excitation increased and the duration of inhibition increased with increased stimulation amplitude. Prolonged inhibition resulted from both after-hyperpolarization currents and GABA-B synaptic transmission. During the paired pulse protocol, the strength of short latency excitation evoked by a test pulse decreased marginally compared to those evoked by a single pulse for interpulse intervals (IPI) < 100 m s. Further, the duration of inhibition evoked by the test pulse was prolonged compared to single pulse for IPIs <50 m s and was not predicted by linear superposition of individual inhibitory responses. For IPIs>50 m s, the duration of inhibition evoked by the test pulse was comparable to those evoked by a single pulse. Short ICMS trains evoked repetitive excitatory responses against a background of inhibition. However, the strength of the repetitive excitatory response declined during ICMS at higher frequencies. Further, the duration of inhibition at the cessation of ICMS at higher frequencies was prolonged compared to the duration following a single pulse. Biomimetic pulse trains evoked comparable neural response between the onset and offset phases despite the presence of stimulation induced inhibition. CONCLUSIONS The cortical column model replicated the short latency excitation and long-lasting inhibitory components of the stereotyped neural response documented in experimental studies of ICMS. Both cellular and synaptic mechanisms influenced the response components generated by ICMS. The non-linear interactions between response components resulted in dynamic ICMS-evoked neural activity and may play an important role in mediating the ICMS-induced precepts.
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Affiliation(s)
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA; Department of Neurobiology, Duke University, Durham, NC, USA; Department of Neurosurgery, Duke University, Durham, NC, USA.
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5
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Huang X, Wei X, Wang J, Yi G. Frequency-dependent membrane polarization across neocortical cell types and subcellular elements by transcranial alternating current stimulation. J Neural Eng 2024; 21:016034. [PMID: 38382101 DOI: 10.1088/1741-2552/ad2b8a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/21/2024] [Indexed: 02/23/2024]
Abstract
Objective.Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that directly interacts with ongoing brain oscillations in a frequency-dependent manner. However, it remains largely unclear how the cellular effects of tACS vary between cell types and subcellular elements.Approach.In this study, we use a set of morphologically realistic models of neocortical neurons to simulate the cellular response to uniform oscillating electric fields (EFs). We systematically characterize the membrane polarization in the soma, axons, and dendrites with varying field directions, intensities, and frequencies.Main results.Pyramidal cells are more sensitive to axial EF that is roughly parallel to the cortical column, while interneurons are sensitive to axial EF and transverse EF that is tangent to the cortical surface. Membrane polarization in each subcellular element increases linearly with EF intensity, and its slope, i.e. polarization length, highly depends on the stimulation frequency. At each frequency, pyramidal cells are more polarized than interneurons. Axons usually experience the highest polarization, followed by the dendrites and soma. Moreover, a visible frequency resonance presents in the apical dendrites of pyramidal cells, while the other subcellular elements primarily exhibit low-pass filtering properties. In contrast, each subcellular element of interneurons exhibits complex frequency-dependent polarization. Polarization phase in each subcellular element of cortical neurons lags that of field and exhibits high-pass filtering properties. These results demonstrate that the membrane polarization is not only frequency-dependent, but also cell type- and subcellular element-specific. Through relating effective length and ion mechanism with polarization, we emphasize the crucial role of cell morphology and biophysics in determining the frequency-dependent membrane polarization.Significance.Our findings highlight the diverse polarization patterns across cell types as well as subcellular elements, which provide some insights into the tACS cellular effects and should be considered when understanding the neural spiking activity by tACS.
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Affiliation(s)
- Xuelin Huang
- School of Electrical and Information Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| | - Xile Wei
- School of Electrical and Information Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| | - Jiang Wang
- School of Electrical and Information Engineering, Tianjin University, Tianjin 300072, People's Republic of China
| | - Guosheng Yi
- School of Electrical and Information Engineering, Tianjin University, Tianjin 300072, People's Republic of China
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Fan Y, Wei X, Lu M, Wang J, Yi G. Electric field effects on neuronal input-output relationship by regulating NMDA spikes. Cogn Neurodyn 2024; 18:199-215. [PMID: 38406200 PMCID: PMC10881955 DOI: 10.1007/s11571-022-09922-y] [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: 10/07/2022] [Revised: 11/23/2022] [Accepted: 12/10/2022] [Indexed: 01/05/2023] Open
Abstract
Evidence shows that the dendritic polarization induced by weak electrical field (EF) can affect the neuronal input-output function via modulating dendritic integration of AMPA synapses, indicating that the supralinear dendritic integration of NMDA synapses can also be influenced by dendritic polarization. However, it remains unknown how dendritic polarization affects NMDA-type dendritic integration, and then contributes to neuronal input-output relationship. Here, we used a computational model of pyramidal neuron with inhomogeneous extracellular potentials to characterize the relationship among EF, dendritic integration, and somatic output. Basing on singular perturbation we analyzed the subthreshold dynamics of membrane potentials in response to NMDA synapses, and found that the equilibrium mapping of a fast subsystem can characterize the asymptotic subthreshold input-output (sI/O) relationship for EF-regulated supralinear dendritic integration, allowing us to predict the tendency of EF-regulated dendritic integration by showing the variation of equilibrium mapping under EF stimulation. EF-induced depolarization at distal dendrites receiving synapses plays a crucial role in shifting the steep change of sI/O left by facilitating dendritic NMDA spike generation and in decreasing the plateau of sI/O via reducing driving force. And more effective EF modulation appears at sparsely activated NMDA receptors compared with clustered synaptic inputs. During the action potential (AP) generation, the respective contribution of EF-regulated dendritic integration and EF-induced somatic polarization was identified to show their synergetic or antagonistic effect on AP generation, depending on neuronal excitability. These results provided insight in understanding the modulation effect of EF on neuronal computation, which is important for optimizing noninvasive brain stimulation. Supplementary Information The online version contains supplementary material available at 10.1007/s11571-022-09922-y.
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Affiliation(s)
- Yaqin Fan
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China
| | - Xile Wei
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China
| | - Meili Lu
- School of Information Technology Engineering, Tianjin University of Technology and Education, Tianjin, 300222 China
| | - Jiang Wang
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China
| | - Guosheng Yi
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China
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Di Lazzaro V, Ranieri F, Bączyk M, de Carvalho M, Dileone M, Dubbioso R, Fernandes S, Kozak G, Motolese F, Ziemann U. Novel approaches to motoneuron disease/ALS treatment using non-invasive brain and spinal stimulation: IFCN handbook chapter. Clin Neurophysiol 2024; 158:114-136. [PMID: 38218077 DOI: 10.1016/j.clinph.2023.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/28/2023] [Accepted: 12/17/2023] [Indexed: 01/15/2024]
Abstract
Non-invasive brain stimulation techniques have been exploited in motor neuron disease (MND) with multifold objectives: to support the diagnosis, to get insights in the pathophysiology of these disorders and, more recently, to slow down disease progression. In this review, we consider how neuromodulation can now be employed to treat MND, with specific attention to amyotrophic lateral sclerosis (ALS), the most common form with upper motoneuron (UMN) involvement, taking into account electrophysiological abnormalities revealed by human and animal studies that can be targeted by neuromodulation techniques. This review article encompasses repetitive transcranial magnetic stimulation methods (including low-frequency, high-frequency, and pattern stimulation paradigms), transcranial direct current stimulation as well as experimental findings with the newer approach of trans-spinal direct current stimulation. We also survey and discuss the trials that have been performed, and future perspectives.
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Affiliation(s)
- Vincenzo Di Lazzaro
- Department of Medicine and Surgery, Unit of Neurology, Neurophysiology, Neurobiology and Psychiatry, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo, 21, 00128 Roma, Italy; Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy.
| | - Federico Ranieri
- Neurology Unit, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, P.Le L.A. Scuro 10, 37134 Verona, Italy
| | - Marcin Bączyk
- Department of Neurobiology, Poznań University of Physical Education, Królowej Jadwigi Street 27/39, 61-871 Poznań, Poland
| | - Mamede de Carvalho
- Institute of Physiology, Institute of Molecular Medicine-JLA, Egas Moniz Study Centre, Faculty of Medicine, University of Lisbon, Lisbon 1649-028, Portugal; Department of Neurosciences and Mental Health, CHULN, Lisbon, Portugal
| | - Michele Dileone
- Faculty of Health Sciences, UCLM Talavera de la Reina, Toledo, Spain; Neurology Department, Hospital Nuestra Señora del Prado, Talavera de la Reina, Toledo, Spain
| | - Raffaele Dubbioso
- Neurophysiology Unit, Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Napoli, Italy
| | - Sofia Fernandes
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016-Lisboa, Portugal
| | - Gabor Kozak
- Department of Neurology and Stroke, University of Tübingen, Tübingen, Germany; Hertie-Institute of Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Francesco Motolese
- Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo, 200, 00128 Roma, Italy
| | - Ulf Ziemann
- Department of Neurology and Stroke, University of Tübingen, Tübingen, Germany; Hertie-Institute of Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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Khalil R, Karim AA, Godde B. Less might be more: 1 mA but not 1.5 mA of tDCS improves tactile orientation discrimination. IBRO Neurosci Rep 2023; 15:186-192. [PMID: 37746157 PMCID: PMC10511473 DOI: 10.1016/j.ibneur.2023.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 08/08/2023] [Accepted: 08/17/2023] [Indexed: 09/26/2023] Open
Abstract
Background Transcranial direct current stimulation (tDCS) is a frequently used brain stimulation method; however, studies on tactile perception using tDCS are inconsistent, which might be explained by the variations in endogenous and exogenous parameters that influence tDCS. Objectives We aimed to investigate the effect of one of these endogenous parameters-the tDCS amplitude-on tactile perception. Methods We conducted this experiment on 28 undergraduates/graduates aged 18-36 years. In separate sessions, participants received 20 min of 1 mA or 1.5 mA current tDCS in a counterbalanced order. Half of the participants received anodal tDCS of the left SI coupled with cathodal tDCS of the right SI, and this montage was reversed for the other half. Pre- and post-tDCS tactile discrimination performance was assessed using the Grating Orientation Task (GOT). In this task, plastic domes with gratings of different widths cut into their surfaces are placed on the fingertip, and participants have to rate the orientation of the gratings. Results Linear modeling with amplitude, dome, and session as within factors and montage as between factors revealed the following: significant main effects of grating width, montage, and session and a marginally significant interaction effect of session and amplitude. Posthoc t-tests indicated that performance in GOT improved after 1 mA but not 1.5 mA tDCS independent of the montage pattern of the electrodes. Conclusion Increasing the stimulation amplitude from 1 mA to 1.5 mA does not facilitate the tDCS effect on GOT performance. On the contrary, the effect seemed more robust for the lower-current amplitude.
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Affiliation(s)
- Radwa Khalil
- School of Business, Social and Decision Sciences, Constructor University, Bremen, Germany
| | - Ahmed A. Karim
- School of Business, Social and Decision Sciences, Constructor University, Bremen, Germany
- Department of Psychiatry and Psychotherapy, University Clinic Tübingen, Tübingen, Germany
- Department of Health Psychology and Neurorehabilitation, SRH Mobile University, Riedlingen, Germany
| | - Ben Godde
- School of Business, Social and Decision Sciences, Constructor University, Bremen, Germany
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Vasu SO, Kaphzan H. Direct Current Stimulation Modulates Synaptic Facilitation via Distinct Presynaptic Calcium Channels. Int J Mol Sci 2023; 24:16866. [PMID: 38069188 PMCID: PMC10706473 DOI: 10.3390/ijms242316866] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/23/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) is a subthreshold neurostimulation technique known for ameliorating neuropsychiatric conditions. The principal mechanism of tDCS is the differential polarization of subcellular neuronal compartments, particularly the axon terminals that are sensitive to external electrical fields. Yet, the underlying mechanism of tDCS is not fully clear. Here, we hypothesized that direct current stimulation (DCS)-induced modulation of presynaptic calcium channel conductance alters axon terminal dynamics with regard to synaptic vesicle release. To examine the involvement of calcium-channel subtypes in tDCS, we recorded spontaneous excitatory postsynaptic currents (sEPSCs) from cortical layer-V pyramidal neurons under DCS while selectively inhibiting distinct subtypes of voltage-dependent calcium channels. Blocking P/Q or N-type calcium channels occluded the effects of DCS on sEPSCs, demonstrating their critical role in the process of DCS-induced modulation of spontaneous vesicle release. However, inhibiting T-type calcium channels did not occlude DCS-induced modulation of sEPSCs, suggesting that despite being active in the subthreshold range, T-type calcium channels are not involved in the axonal effects of DCS. DCS modulates synaptic facilitation by regulating calcium channels in axon terminals, primarily via controlling P/Q and N-type calcium channels, while T-type calcium channels are not involved in this mechanism.
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Affiliation(s)
| | - Hanoch Kaphzan
- Sagol Department of Neurobiology, University of Haifa, Haifa 3103301, Israel
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10
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Rogers ER, Mirzakhalili E, Lempka SF. Model-based analysis of subthreshold mechanisms of spinal cord stimulation for pain. J Neural Eng 2023; 20:066003. [PMID: 37906966 PMCID: PMC10632558 DOI: 10.1088/1741-2552/ad0858] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/11/2023] [Accepted: 10/31/2023] [Indexed: 11/02/2023]
Abstract
Objective.Spinal cord stimulation (SCS) is a common treatment for chronic pain. For decades, SCS maximized overlap between stimulation-induced paresthesias and the patient's painful areas. Recently developed SCS paradigms relieve pain at sub-perceptible amplitudes, yet little is known about the neural response to these new waveforms or their analgesic mechanisms of action. Therefore, in this study, we investigated the neural response to multiple forms of paresthesia-free SCS.Approach.We used computational modeling to investigate the neurophysiological effects and the plausibility of commonly proposed mechanisms of three paresthesia-free SCS paradigms: burst, 1 kHz, and 10 kHz SCS. Specifically, in C- and Aβ-fibers, we investigated the effects of different SCS waveforms on spike timing and activation thresholds, as well as how stochastic ion channel gating affects the response of dorsal column axons. Finally, we characterized membrane polarization of superficial dorsal horn neurons.Main results.We found that none of the SCS waveforms activate nor modulate spike timing in C-fibers. Spike timing was modulated in Aβ-fibers only at suprathreshold amplitudes. Ion channel stochasticity had little effect on Aβ-fiber activation thresholds but produced heterogeneous spike timings at suprathreshold amplitudes. Finally, local cells were preferentially polarized in their axon terminals, and the magnitude of this polarization was dependent on cellular morphology and position relative to the stimulation electrodes.Significance.Overall, the mechanisms of action of subparesthetic SCS remain unclear. Our results suggest that no SCS waveforms directly activate C-fibers, and modulation of spike timing is unlikely at subthreshold amplitudes. We conclude that potential subthreshold neuromodulatory effects of SCS on local cells are likely to be presynaptic in nature, as axons are preferentially depolarized during SCS.
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Affiliation(s)
- Evan R Rogers
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Ehsan Mirzakhalili
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States of America
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11
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Guidetti M, Maria Bianchi A, Parazzini M, Maiorana N, Bonato M, Ferrara R, Libelli G, Montemagno K, Ferrucci R, Priori A, Bocci T. Monopolar tDCS might affect brainstem reflexes: A computational and neurophysiological study. Clin Neurophysiol 2023; 155:44-54. [PMID: 37690391 DOI: 10.1016/j.clinph.2023.08.011] [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: 06/06/2023] [Revised: 08/04/2023] [Accepted: 08/12/2023] [Indexed: 09/12/2023]
Abstract
OBJECTIVE To assess whether monopolar multi-electrode transcranial direct current stimulation (tDCS) montages might selectively affect deep brain structures through computational predictions and neurophysiological assessment. METHODS Electric field distribution in deep brain structures (i.e., thalamus and midbrain) were estimated through computational models simulating tDCS with two monopolar and two monopolar multi-electrode montages. Monopolar multi-electrode tDCS was then applied to healthy subject, and effects on pontine and medullary circuitries was evaluated studying changes in blink reflex (BR) and masseter inhibitory reflex (MIR). RESULTS Computational results suggest that tDCS with monopolar multi-electrode montages might induce electric field intensities in deep brain structure comparable to those in grey matter, while neurophysiological results disclosed that BR and MIR were selectively modulated by tDCS only when cathode was placed over the right deltoid. CONCLUSIONS Multi-electrode tDCS (anodes over motor cortices, cathode over right deltoid) could induce significant electric fields in the thalamus and midbrain, and selectively affect brainstem neural circuits. SIGNIFICANCE Multi-electrode tDCS (anodes over motor cortices, cathode over right deltoid) might be further explored to affect brainstem activity, also in the context of non-invasive deep brain stimulation.
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Affiliation(s)
- Matteo Guidetti
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy; Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan, Italy
| | - Anna Maria Bianchi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan, Italy
| | - Marta Parazzini
- Institute of Electronics, Computer and Telecommunication Engineering (IEIIT), CNR, 20133 Milan, Italy
| | - Natale Maiorana
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Marta Bonato
- Institute of Electronics, Computer and Telecommunication Engineering (IEIIT), CNR, 20133 Milan, Italy
| | - Rosanna Ferrara
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Giorgia Libelli
- Neurology Unit, Department of Medicine and Surgery, University of Parma, Via Gramsci 14, 43126 Parma, Italy
| | - Kora Montemagno
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Roberta Ferrucci
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy; Clinical Neurology Unit, "Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo", Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Alberto Priori
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy; Clinical Neurology Unit, "Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo", Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy
| | - Tommaso Bocci
- "Aldo Ravelli" Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy; Clinical Neurology Unit, "Azienda Socio-Sanitaria Territoriale Santi Paolo E Carlo", Department of Health Sciences, University of Milan, Via Antonio di Rudinì 8, 20142 Milan, Italy.
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12
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Aberra AS, Wang R, Grill WM, Peterchev AV. Multi-scale model of axonal and dendritic polarization by transcranial direct current stimulation in realistic head geometry. Brain Stimul 2023; 16:1776-1791. [PMID: 38056825 PMCID: PMC10842743 DOI: 10.1016/j.brs.2023.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 11/06/2023] [Accepted: 11/29/2023] [Indexed: 12/08/2023] Open
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation modality that can alter cortical excitability. However, it remains unclear how the subcellular elements of different neuron types are polarized by specific electric field (E-field) distributions. OBJECTIVE To quantify neuronal polarization generated by tDCS in a multi-scale computational model. METHODS We embedded layer-specific, morphologically-realistic cortical neuron models in a finite element model of the E-field in a human head and simulated steady-state polarization generated by conventional primary-motor-cortex-supraorbital (M1-SO) and 4 × 1 high-definition (HD) tDCS. We quantified somatic, axonal, and dendritic polarization of excitatory pyramidal cells in layers 2/3, 5, and 6, as well as inhibitory interneurons in layers 1 and 4 of the hand knob. RESULTS Axonal and dendritic terminals were polarized more than the soma in all neurons, with peak axonal and dendritic polarization of 0.92 mV and 0.21 mV, respectively, compared to peak somatic polarization of 0.07 mV for 1.8 mA M1-SO stimulation. Both montages generated regions of depolarization and hyperpolarization beneath the M1 anode; M1-SO produced slightly stronger, more diffuse polarization peaking in the central sulcus, while 4 × 1 HD produced higher peak polarization in the gyral crown. The E-field component normal to the cortical surface correlated strongly with pyramidal neuron somatic polarization (R2>0.9), but exhibited weaker correlations with peak pyramidal axonal and dendritic polarization (R2:0.5-0.9) and peak polarization in all subcellular regions of interneurons (R2:0.3-0.6). Simulating polarization by uniform local E-field extracted at the soma approximated the spatial distribution of tDCS polarization but produced large errors in some regions (median absolute percent error: 7.9 %). CONCLUSIONS Polarization of pre- and postsynaptic compartments of excitatory and inhibitory cortical neurons may play a significant role in tDCS neuromodulation. These effects cannot be predicted from the E-field distribution alone but rather require calculation of the neuronal response.
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Affiliation(s)
- Aman S Aberra
- Dept. of Biomedical Engineering, Pratt School of Engineering, Duke University, NC, USA.
| | - Ruochen Wang
- Dept. of Biomedical Engineering, Pratt School of Engineering, Duke University, NC, USA; Dept. of Psychiatry and Behavioral Sciences, School of Medicine, Duke University, NC, USA.
| | - Warren M Grill
- Dept. of Biomedical Engineering, Pratt School of Engineering, Duke University, NC, USA; Dept. of Electrical and Computer Engineering, Pratt School of Engineering, Duke University, NC, USA; Dept. of Neurobiology, School of Medicine, Duke University, NC, USA; Dept. of Neurosurgery, School of Medicine, Duke University, NC, USA.
| | - Angel V Peterchev
- Dept. of Biomedical Engineering, Pratt School of Engineering, Duke University, NC, USA; Dept. of Psychiatry and Behavioral Sciences, School of Medicine, Duke University, NC, USA; Dept. of Electrical and Computer Engineering, Pratt School of Engineering, Duke University, NC, USA; Dept. of Neurosurgery, School of Medicine, Duke University, NC, USA.
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13
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Fan Y, Wei X, Lu M, Wang J, Yi G. State-dependent modulation of low-threshold-current-regulated dendritic Ca 2+ response in thalamic reticular neurons with extracellular electric fields. Sci Rep 2023; 13:16485. [PMID: 37779115 PMCID: PMC10543533 DOI: 10.1038/s41598-023-43611-y] [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: 07/06/2023] [Accepted: 09/26/2023] [Indexed: 10/03/2023] Open
Abstract
Deep brain stimulation (DBS) in thalamic reticular nucleus (TRN) neuron provides a novel treatment for drug-resistant epilepsy via the induced electrical field (EFs). However, the mechanisms underlying EF effects remain unclear. This paper investigated how EFs regulate low-threshold dendritic Ca2+ (dCa) response and thus contribute to the input-output relationship of TRN cell. Our results showed that EFs modulate firing modes differently in a neuronal state-dependent manner. At the depolarized state, EFs only regulate the spike timing of a somatic stimulus-evoked single action potential (AP) with less contribution in the regulation of dCa response but could induce the transition between a dendritic stimulus-evoked single AP and a tonic burst of APs via the moderate regulation of dCa response. At the hyperpolarized state, EFs have significant effects on the dCa response, which modulate the large dCa response-dependent burst discharge and even cause a transition from this type of burst discharge to a single AP with less dCa response. Moreover, EF effects on stimulation threshold of somatic spiking prominently depend on EF-regulated dCa responses and the onset time differences between the stimulus and EF give rise to the distinct effect in the EF regulation of dCa responses. Finally, the larger neuronal axial resistance tends to result in the dendritic stimulus-evoked dCa response independent of somatic state. Interestingly, in this case, the EF application could reproduce the similar somatic state-dependent dCa response to dendritic stimulus which occurs in the case of lower axial resistance. These results suggest that the influence of EF on neuronal activities depends on neuronal intrinsic properties, which provides insight into understanding how DBS in TRN neuron modulates epilepsy from the point of view of biophysics.
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Affiliation(s)
- Yaqin Fan
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China
| | - Xile Wei
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China
| | - Meili Lu
- School of Information Technology Engineering, Tianjin University of Technology and Education, Tianjin, 300222, China
| | - Jiang Wang
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China
| | - Guosheng Yi
- Tianjin Key Laboratory of Process Measurement and Control, School of Electrical and Information Engineering, Tianjin University, Tianjin, China.
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14
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Mirzakhalili E, Rogers ER, Lempka SF. An optimization framework for targeted spinal cord stimulation. J Neural Eng 2023; 20:056026. [PMID: 37647885 PMCID: PMC10535048 DOI: 10.1088/1741-2552/acf522] [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: 06/05/2023] [Revised: 08/14/2023] [Accepted: 08/30/2023] [Indexed: 09/01/2023]
Abstract
Objective. Spinal cord stimulation (SCS) is a common neurostimulation therapy to manage chronic pain. Technological advances have produced new neurostimulation systems with expanded capabilities in an attempt to improve the clinical outcomes associated with SCS. However, these expanded capabilities have dramatically increased the number of possible stimulation parameters and made it intractable to efficiently explore this large parameter space within the context of standard clinical programming procedures. Therefore, in this study, we developed an optimization approach to define the optimal current amplitudes or fractions across individual contacts in an SCS electrode array(s).Approach. We developed an analytic method using the Lagrange multiplier method along with smoothing approximations. To test our optimization framework, we used a hybrid computational modeling approach that consisted of a finite element method model and multi-compartment models of axons and cells within the spinal cord. Moreover, we extended our approach to multi-objective optimization to explore the trade-off between activating regions of interest (ROIs) and regions of avoidance (ROAs).Main results. For simple ROIs, our framework suggested optimized configurations that resembled simple bipolar configurations. However, when we considered multi-objective optimization, our framework suggested nontrivial stimulation configurations that could be selected from Pareto fronts to target multiple ROIs or avoid ROAs.Significance. We developed an optimization framework for targeted SCS. Our method is analytic, which allows for the fast calculation of optimal solutions. For the first time, we provided a multi-objective approach for selective SCS. Through this approach, we were able to show that novel configurations can provide neural recruitment profiles that are not possible with conventional stimulation configurations (e.g. bipolar stimulation). Most importantly, once integrated with computational models that account for sources of interpatient variability (e.g. anatomy, electrode placement), our optimization framework can be utilized to provide stimulation settings tailored to the needs of individual patients.
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Affiliation(s)
- Ehsan Mirzakhalili
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Evan R Rogers
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States of America
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15
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Aberra AS, Wang R, Grill WM, Peterchev AV. Multi-scale model of axonal and dendritic polarization by transcranial direct current stimulation in realistic head geometry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.23.554447. [PMID: 37767087 PMCID: PMC10522328 DOI: 10.1101/2023.08.23.554447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Background Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation modality that can alter cortical excitability. However, it remains unclear how the subcellular elements of different neuron types are polarized by specific electric field (E-field) distributions. Objective To quantify neuronal polarization generated by tDCS in a multi-scale computational model. Methods We embedded layer-specific, morphologically-realistic cortical neuron models in a finite element model of the E-field in a human head and simulated steady-state polarization generated by conventional primary-motor-cortex-supraorbital (M1-SO) and 4×1 high-definition (HD) tDCS. We quantified somatic, axonal, and dendritic polarization of excitatory pyramidal cells in layers 2/3, 5, and 6, as well as inhibitory interneurons in layers 1 and 4 of the hand knob. Results Axonal and dendritic terminals were polarized more than the soma in all neurons, with peak axonal and dendritic polarization of 0.92 mV and 0.21 mV, respectively, compared to peak somatic polarization of 0.07 mV for 1.8 mA M1-SO stimulation. Both montages generated regions of depolarization and hyperpolarization beneath the M1 anode; M1-SO produced slightly stronger, more diffuse polarization peaking in the central sulcus, while 4×1 HD produced higher peak polarization in the gyral crown. Simulating polarization by uniform local E-field approximated the spatial distribution of tDCS polarization but produced large errors in some regions. Conclusions Polarization of pre- and postsynaptic compartments of excitatory and inhibitory cortical neurons may play a significant role in tDCS neuromodulation. These effects cannot be predicted from the E-field distribution alone but rather require calculation of the neuronal response.
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16
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Liang L, Damiani A, Del Brocco M, Rogers ER, Jantz MK, Fisher LE, Gaunt RA, Capogrosso M, Lempka SF, Pirondini E. A systematic review of computational models for the design of spinal cord stimulation therapies: from neural circuits to patient-specific simulations. J Physiol 2023; 601:3103-3121. [PMID: 36409303 PMCID: PMC10259770 DOI: 10.1113/jp282884] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 11/08/2022] [Indexed: 08/02/2023] Open
Abstract
Seventy years ago, Hodgkin and Huxley published the first mathematical model to describe action potential generation, laying the foundation for modern computational neuroscience. Since then, the field has evolved enormously, with studies spanning from basic neuroscience to clinical applications for neuromodulation. Computer models of neuromodulation have evolved in complexity and personalization, advancing clinical practice and novel neurostimulation therapies, such as spinal cord stimulation. Spinal cord stimulation is a therapy widely used to treat chronic pain, with rapidly expanding indications, such as restoring motor function. In general, simulations contributed dramatically to improve lead designs, stimulation configurations, waveform parameters and programming procedures and provided insight into potential mechanisms of action of electrical stimulation. Although the implementation of neural models are relentlessly increasing in number and complexity, it is reasonable to ask whether this observed increase in complexity is necessary for improved accuracy and, ultimately, for clinical efficacy. With this aim, we performed a systematic literature review and a qualitative meta-synthesis of the evolution of computational models, with a focus on complexity, personalization and the use of medical imaging to capture realistic anatomy. Our review showed that increased model complexity and personalization improved both mechanistic and translational studies. More specifically, the use of medical imaging enabled the development of patient-specific models that can help to transform clinical practice in spinal cord stimulation. Finally, we combined our results to provide clear guidelines for standardization and expansion of computational models for spinal cord stimulation.
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Affiliation(s)
- Lucy Liang
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Arianna Damiani
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
| | - Matteo Del Brocco
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
| | - Evan R Rogers
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Maria K Jantz
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Lee E Fisher
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
| | - Robert A Gaunt
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
| | - Marco Capogrosso
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | - Elvira Pirondini
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA
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17
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Makaroff SN, Nummenmaa AR, Noetscher GM, Qi Z, McIntyre CC, Bingham CS. Influence of charges deposited on membranes of human hyperdirect pathway axons on depolarization during subthalamic deep brain stimulation. J Neural Eng 2023; 20:10.1088/1741-2552/ace5de. [PMID: 37429285 PMCID: PMC10542971 DOI: 10.1088/1741-2552/ace5de] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 07/10/2023] [Indexed: 07/12/2023]
Abstract
Objective.The motor hyperdirect pathway (HDP) is a key target in the treatment of Parkinson's disease with deep brain stimulation (DBS). Biophysical models of HDP DBS have been used to explore the mechanisms of stimulation. Built upon finite element method volume conductor solutions, such models are limited by a resolution mismatch, where the volume conductor is modeled at the macro scale, while the neural elements are at the micro scale. New techniques are needed to better integrate volume conductor models with neuron models.Approach.We simulated subthalamic DBS of the human HDP using finely meshed axon models to calculate surface charge deposition on insulting membranes of nonmyelinated axons. We converted the corresponding double layer extracellular problem to a single layer problem and applied the well-conditioned charge-based boundary element fast multipole method (BEM-FMM) with unconstrained numerical spatial resolution. Commonly used simplified estimations of membrane depolarization were compared with more realistic solutions.Main result.Neither centerline potential nor estimates of axon recruitment were impacted by the estimation method used except at axon bifurcations and hemispherical terminations. Local estimates of axon polarization were often much higher at bifurcations and terminations than at any other place along the axon and terminal arbor. Local average estimates of terminal electric field are higher by 10%-20%.Significance. Biophysical models of action potential initiation in the HDP suggest that axon terminations are often the lowest threshold elements for activation. The results of this study reinforce that hypothesis and suggest that this phenomenon is even more pronounced than previously realized.
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Affiliation(s)
- Sergey N Makaroff
- Electrical and Computer Engineering Department, Worcester Polytechnic Institution, Worcester, MA 01609, United States of America
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Aapo R Nummenmaa
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Gregory M Noetscher
- Electrical and Computer Engineering Department, Worcester Polytechnic Institution, Worcester, MA 01609, United States of America
- ARMY DEVCOM-SC, General Greene Ave, Natick, MA 01760, United States of America
| | - Zhen Qi
- Electrical and Computer Engineering Department, Worcester Polytechnic Institution, Worcester, MA 01609, United States of America
| | - Cameron C McIntyre
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
- Department of Neurosurgery, Duke University, Durham, NC 27710, United States of America
| | - Clayton S Bingham
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
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Majdi A, Asamoah B, Mc Laughlin M. Reinterpreting published tDCS results in terms of a cranial and cervical nerve co-stimulation mechanism. Front Hum Neurosci 2023; 17:1101490. [PMID: 37415857 PMCID: PMC10320219 DOI: 10.3389/fnhum.2023.1101490] [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: 11/17/2022] [Accepted: 05/31/2023] [Indexed: 07/08/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation method that has been used to alter cognition in hundreds of experiments. During tDCS, a low-amplitude current is delivered via scalp electrodes to create a weak electric field in the brain. The weak electric field causes membrane polarization in cortical neurons directly under the scalp electrodes. It is generally assumed that this mechanism causes the observed effects of tDCS on cognition. However, it was recently shown that some tDCS effects are not caused by the electric field in the brain but rather via co-stimulation of cranial and cervical nerves in the scalp that also have neuromodulatory effects that can influence cognition. This peripheral nerve co-stimulation mechanism is not controlled for in tDCS experiments that use the standard sham condition. In light of this new evidence, results from previous tDCS experiments could be reinterpreted in terms of a peripheral nerve co-stimulation mechanism. Here, we selected six publications that reported tDCS effects on cognition and attributed the effects to the electric field in the brain directly under the electrode. We then posed the question: given the known neuromodulatory effects of cranial and cervical nerve stimulation, could the reported results also be understood in terms of tDCS peripheral nerve co-stimulation? We present our re-interpretation of these results as a way to stimulate debate within the neuromodulation field and as a food-for-thought for researchers designing new tDCS experiments.
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Affiliation(s)
- Alireza Majdi
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Boateng Asamoah
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Myles Mc Laughlin
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Leuven Brain Institute, KU Leuven, Leuven, Belgium
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Pinotsis DA, Fridman G, Miller EK. Cytoelectric Coupling: Electric fields sculpt neural activity and "tune" the brain's infrastructure. Prog Neurobiol 2023; 226:102465. [PMID: 37210066 DOI: 10.1016/j.pneurobio.2023.102465] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/09/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023]
Abstract
We propose and present converging evidence for the Cytoelectric Coupling Hypothesis: Electric fields generated by neurons are causal down to the level of the cytoskeleton. This could be achieved via electrodiffusion and mechanotransduction and exchanges between electrical, potential and chemical energy. Ephaptic coupling organizes neural activity, forming neural ensembles at the macroscale level. This information propagates to the neuron level, affecting spiking, and down to molecular level to stabilize the cytoskeleton, "tuning" it to process information more efficiently.
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Affiliation(s)
- Dimitris A Pinotsis
- Centre for Mathematical Neuroscience and Psychology and Department of Psychology, City -University of London, London EC1V 0HB, United Kingdom; The Picower Institute for Learning & Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Gene Fridman
- Departments of Otolaryngology, Biomedical Engineering, and Electrical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Earl K Miller
- The Picower Institute for Learning & Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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20
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A microfluidic perspective on conventional in vitro transcranial direct current stimulation methods. J Neurosci Methods 2023; 385:109761. [PMID: 36470469 PMCID: PMC9884911 DOI: 10.1016/j.jneumeth.2022.109761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/20/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022]
Abstract
Transcranial direct current stimulation (tDCS) is a promising non-invasive brain stimulation method to treat neurological and psychiatric diseases. However, its underlying neural mechanisms warrant further investigation. Indeed, dose-response interrelations are poorly understood. Placing explanted brain tissue, mostly from mice or rats, into a uniform direct current electric field (dcEF) is a well-established in vitro system to elucidate the neural mechanism of tDCS. Nevertheless, we will show that generating a defined, uniform, and constant dcEF throughout a brain slice is challenging. This article critically reviews the methods used to generate and calibrate a uniform dcEF. We use finite element analysis (FEA) to evaluate the widely used parallel electrode configuration and show that it may not reliably generate uniform dcEF within a brain slice inside an open interface or submerged chamber. Moreover, equivalent circuit analysis and measurements inside a testing chamber suggest that calibrating the dcEF intensity with two recording electrodes can inaccurately capture the true EF magnitude in the targeted tissue when specific criteria are not met. Finally, we outline why microfluidic chambers are an effective and calibration-free approach of generating spatiotemporally uniform dcEF for DCS in vitro studies, facilitating accurate and fine-scale dcEF adjustments. We are convinced that improving the precision and addressing the limitations of current experimental platforms will substantially improve the reproducibility of in vitro experimental results. A better mechanistic understanding of dose-response relations will ultimately facilitate more effective non-invasive stimulation therapies in patients.
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21
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Khadka N, Bikson M. Neurocapillary-Modulation. Neuromodulation 2022; 25:1299-1311. [PMID: 33340187 PMCID: PMC8213863 DOI: 10.1111/ner.13338] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 11/05/2020] [Accepted: 11/23/2020] [Indexed: 02/06/2023]
Abstract
OBJECTIVES We consider two consequences of brain capillary ultrastructure in neuromodulation. First, blood-brain barrier (BBB) polarization as a consequence of current crossing between interstitial space and the blood. Second, interstitial current flow distortion around capillaries impacting neuronal stimulation. MATERIALS AND METHODS We developed computational models of BBB ultrastructure morphologies to first assess electric field amplification at the BBB (principle 1) and neuron polarization amplification by the presence of capillaries (principle 2). We adapt neuron cable theory to develop an analytical solution for maximum BBB polarization sensitivity. RESULTS Electrical current crosses between the brain parenchyma (interstitial space) and capillaries, producing BBB electric fields (EBBB) that are >400x of the average parenchyma electric field (ĒBRAIN), which in turn modulates transport across the BBB. Specifically, for a BBB space constant (λBBB) and wall thickness (dth-BBB), the analytical solution for maximal BBB electric field (EABBB) is given as: (ĒBRAIN × λBBB)/dth-BBB. Electrical current in the brain parenchyma is distorted around brain capillaries, amplifying neuronal polarization. Specifically, capillary ultrastructure produces ∼50% modulation of the ĒBRAIN over the ∼40 μm inter-capillary distance. The divergence of EBRAIN (Activating function) is thus ∼100 kV/m2 per unit ĒBRAIN. CONCLUSIONS BBB stimulation by principle 1 suggests novel therapeutic strategies such as boosting metabolic capacity or interstitial fluid clearance. Whereas the spatial profile of EBRAIN is traditionally assumed to depend only on macroscopic anatomy, principle 2 suggests a central role for local capillary ultrastructure-which impact forms of neuromodulation including deep brain stimulation (DBS), spinal cord stimulation (SCS), transcranial magnetic stimulation (TMS), electroconvulsive therapy (ECT), and transcranial electrical stimulation (tES)/transcranial direct current stimulation (tDCS).
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Affiliation(s)
- Niranjan Khadka
- Department of Psychiatry, Laboratory for Neuropsychiatry and Neuromodulation, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, USA.
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22
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Brain network modulation in Alzheimer's and frontotemporal dementia with transcranial electrical stimulation. Neurobiol Aging 2022; 111:24-34. [DOI: 10.1016/j.neurobiolaging.2021.11.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 11/19/2022]
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23
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Rogers ER, Zander HJ, Lempka SF. Neural Recruitment During Conventional, Burst, and 10-kHz Spinal Cord Stimulation for Pain. THE JOURNAL OF PAIN 2022; 23:434-449. [PMID: 34583022 PMCID: PMC8925309 DOI: 10.1016/j.jpain.2021.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 09/09/2021] [Accepted: 09/11/2021] [Indexed: 10/20/2022]
Abstract
Spinal cord stimulation (SCS) is a popular neurostimulation therapy for severe chronic pain. To improve stimulation efficacy, multiple modes are now used clinically, including conventional, burst, and 10-kHz SCS. Clinical observations have produced speculation that these modes target different neural elements and/or work via distinct mechanisms of action. However, in humans, these hypotheses cannot be conclusively answered via experimental methods. Therefore, we utilized computational modeling to assess the response of primary afferents, interneurons, and projection neurons to conventional, burst, and 10-kHz SCS. We found that local cell thresholds were always higher than afferent thresholds, arguing against direct recruitment of these local cells. Furthermore, although we observed relative threshold differences between conventional, burst, and 10-kHz SCS, the recruitment order was the same. Finally, contrary to previous reports, axon collateralization produced complex changes in activation thresholds of primary afferents. These results motivate future work to contextualize clinical observations across SCS paradigms. PERSPECTIVE: This article presents the first computational modeling study to investigate neural recruitment during conventional, burst, and 10-kilohertz spinal cord stimulation for chronic pain within a single modeling framework. The results provide insight into these treatments' unknown mechanisms of action and offer context to interpreting clinical observations.
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Affiliation(s)
- Evan R. Rogers
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Hans J. Zander
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Scott F. Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA,Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
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24
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Key factors in the cortical response to transcranial electrical Stimulations—A multi-scale modeling study. Comput Biol Med 2022; 144:105328. [DOI: 10.1016/j.compbiomed.2022.105328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 01/26/2022] [Accepted: 02/14/2022] [Indexed: 11/24/2022]
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25
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Liu X, Qiu F, Hou L, Wang X. Review of Noninvasive or Minimally Invasive Deep Brain Stimulation. Front Behav Neurosci 2022; 15:820017. [PMID: 35145384 PMCID: PMC8823253 DOI: 10.3389/fnbeh.2021.820017] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/27/2021] [Indexed: 12/11/2022] Open
Abstract
Brain stimulation is a critical technique in neuroscience research and clinical application. Traditional transcranial brain stimulation techniques, such as transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and deep brain stimulation (DBS) have been widely investigated in neuroscience for decades. However, TMS and tDCS have poor spatial resolution and penetration depth, and DBS requires electrode implantation in deep brain structures. These disadvantages have limited the clinical applications of these techniques. Owing to developments in science and technology, substantial advances in noninvasive and precise deep stimulation have been achieved by neuromodulation studies. Second-generation brain stimulation techniques that mainly rely on acoustic, electronic, optical, and magnetic signals, such as focused ultrasound, temporal interference, near-infrared optogenetic, and nanomaterial-enabled magnetic stimulation, offer great prospects for neuromodulation. This review summarized the mechanisms, development, applications, and strengths of these techniques and the prospects and challenges in their development. We believe that these second-generation brain stimulation techniques pave the way for brain disorder therapy.
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Affiliation(s)
- Xiaodong Liu
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Fang Qiu
- Department of Exercise Physiology, Beijing Sport University, Beijing, China
| | - Lijuan Hou
- College of Physical Education and Sports, Beijing Normal University, Beijing, China
- *Correspondence: Lijuan Hou Xiaohui Wang
| | - Xiaohui Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
- *Correspondence: Lijuan Hou Xiaohui Wang
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26
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Kumaravelu K, Sombeck J, Miller LE, Bensmaia SJ, Grill WM. Stoney vs. Histed: Quantifying the spatial effects of intracortical microstimulation. Brain Stimul 2022; 15:141-151. [PMID: 34861412 PMCID: PMC8816873 DOI: 10.1016/j.brs.2021.11.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Intracortical microstimulation (ICMS) is used to map neural circuits and restore lost sensory modalities such as vision, hearing, and somatosensation. The spatial effects of ICMS remain controversial: Stoney and colleagues proposed that the volume of somatic activation increased with stimulation intensity, while Histed et al., suggested activation density, but not somatic activation volume, increases with stimulation intensity. OBJECTIVE We used computational modeling to quantify the spatial effects of ICMS intensity and unify the apparently paradoxical findings of Histed and Stoney. METHODS We implemented a biophysically-based computational model of a cortical column comprising neurons with realistic morphology and representative synapses. We quantified the spatial effects of single pulses and short trains of ICMS, including the volume of activated neurons and the density of activated neurons as a function of stimulation intensity. RESULTS At all amplitudes, the dominant mode of somatic activation was by antidromic propagation to the soma following axonal activation, rather than via transsynaptic activation. There were no occurrences of direct activation of somata or dendrites. The volume over which antidromic action potentials were initiated grew with stimulation amplitude, while the volume of somatic activation increased marginally. However, the density of somatic activation within the activated volume increased with stimulation amplitude. CONCLUSIONS The results resolve the apparent paradox between Stoney and Histed's results by demonstrating that the volume over which action potentials are initiated grows with ICMS amplitude, consistent with Stoney. However, the volume occupied by the activated somata remains approximately constant, while the density of activated neurons within that volume increase, consistent with Histed.
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Affiliation(s)
| | - Joseph Sombeck
- Department of Physiology, Northwestern University, Chicago, IL,Department of Biomedical Engineering, Northwestern University, Chicago, IL
| | - Lee E. Miller
- Department of Physiology, Northwestern University, Chicago, IL,Department of Biomedical Engineering, Northwestern University, Chicago, IL,Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL
| | - Sliman J. Bensmaia
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL,Committee on Computational Neuroscience, University of Chicago, Chicago, IL,Neuroscience Institute, University of Chicago, Chicago, IL
| | - Warren M. Grill
- Department of Biomedical Engineering, Duke University, Durham, NC,Department of Electrical and Computer Engineering, Duke University, Durham, NC,Department of Neurobiology, Duke University, Durham, NC,Department of Neurosurgery, Duke University, Durham, NC,Correspondence: Warren M. Grill, Ph.D., Duke University, Department of Biomedical Engineering, Rm. 1427, Fitzpatrick CIEMAS, 101 Science Drive, Campus Box 90281, Durham, NC, 27708, USA, , 919 660-5276 Phone, 919 684-4488 FAX
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27
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Direct Current Stimulation in Cell Culture Systems and Brain Slices-New Approaches for Mechanistic Evaluation of Neuronal Plasticity and Neuromodulation: State of the Art. Cells 2021; 10:cells10123583. [PMID: 34944091 PMCID: PMC8700319 DOI: 10.3390/cells10123583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/09/2021] [Accepted: 12/16/2021] [Indexed: 12/21/2022] Open
Abstract
Non-invasive direct current stimulation (DCS) of the human brain induces neuronal plasticity and alters plasticity-related cognition and behavior. Numerous basic animal research studies focusing on molecular and cellular targets of DCS have been published. In vivo, ex vivo, and in vitro models enhanced knowledge about mechanistic foundations of DCS effects. Our review identified 451 papers using a PRISMA-based search strategy. Only a minority of these papers used cell culture or brain slice experiments with DCS paradigms comparable to those applied in humans. Most of the studies were performed in brain slices (9 papers), whereas cell culture experiments (2 papers) were only rarely conducted. These ex vivo and in vitro approaches underline the importance of cell and electric field orientation, cell morphology, cell location within populations, stimulation duration (acute, prolonged, chronic), and molecular changes, such as Ca2+-dependent intracellular signaling pathways, for the effects of DC stimulation. The reviewed studies help to clarify and confirm basic mechanisms of this intervention. However, the potential of in vitro studies has not been fully exploited and a more systematic combination of rodent models, ex vivo, and cellular approaches might provide a better insight into the neurophysiological changes caused by tDCS.
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28
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Zannou AL, Khadka N, FallahRad M, Truong DQ, Kopell BH, Bikson M. Tissue Temperature Increases by a 10 kHz Spinal Cord Stimulation System: Phantom and Bioheat Model. Neuromodulation 2021; 24:1327-1335. [PMID: 31225695 PMCID: PMC6925358 DOI: 10.1111/ner.12980] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 05/10/2019] [Accepted: 05/11/2019] [Indexed: 12/30/2022]
Abstract
OBJECTIVE A recently introduced Spinal Cord Stimulation (SCS) system operates at 10 kHz, faster than conventional SCS systems, resulting in significantly more power delivered to tissues. Using a SCS heat phantom and bioheat multi-physics model, we characterized tissue temperature increases by this 10 kHz system. We also evaluated its Implanted Pulse Generator (IPG) output compliance and the role of impedance in temperature increases. MATERIALS AND METHODS The 10 kHz SCS system output was characterized under resistive loads (1-10 KΩ). Separately, fiber optic temperature probes quantified temperature increases (ΔTs) around the SCS lead in specially developed heat phantoms. The role of stimulation Level (1-7; ideal pulse peak-to-peak of 1-7mA) was considered, specifically in the context of stimulation current Root Mean Square (RMS). Data from the heat phantom were verified with the SCS heat-transfer models. A custom high-bandwidth stimulator provided 10 kHz pulses and sinusoidal stimulation for control experiments. RESULTS The 10 kHz SCS system delivers 10 kHz biphasic pulses (30-20-30 μs). Voltage compliance was 15.6V. Even below voltage compliance, IPG bandwidth attenuated pulse waveform, limiting applied RMS. Temperature increased supralinearly with stimulation Level in a manner predicted by applied RMS. ΔT increases with Level and impedance until stimulator compliance was reached. Therefore, IPG bandwidth and compliance dampen peak heating. Nonetheless, temperature increases predicted by bioheat multi-physic models (ΔT = 0.64°C and 1.42°C respectively at Level 4 and 7 at the cervical segment; ΔT = 0.68°C and 1.72°C respectively at Level 4 and 7 at the thoracic spinal cord)-within ranges previously reported to effect neurophysiology. CONCLUSIONS Heating of spinal tissues by this 10 kHz SCS system theoretically increases quickly with stimulation level and load impedance, while dampened by IPG pulse bandwidth and voltage compliance limitations. If validated in vivo as a mechanism of kHz SCS, bioheat models informed by IPG limitations allow prediction and optimization of temperature changes.
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Affiliation(s)
- Adantchede L Zannou
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031
| | - Niranjan Khadka
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031
| | - Mohamad FallahRad
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031
| | - Dennis Q. Truong
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031
| | - Brian H. Kopell
- Department of Neurosurgery, Neurology, Psychiatry and Neuroscience, The Icahn School of Medicine, Mount Sinai, New York, NY
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, New York, NY 10031
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29
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Amplitude modulated transcranial alternating current stimulation (AM-TACS) efficacy evaluation via phosphene induction. Sci Rep 2021; 11:22245. [PMID: 34782626 PMCID: PMC8593032 DOI: 10.1038/s41598-021-01482-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 10/18/2021] [Indexed: 12/01/2022] Open
Abstract
Amplitude modulated transcranial alternating current stimulation (AM-tACS) is a novel method of electrostimulation which enables the recording of electrophysiological signals during stimulation, thanks to an easier removable stimulation artefact compared to classical electrostimulation methods. To gauge the neuromodulatory potential of AM-tACS, we tested its capacity to induce phosphenes as an indicator of stimulation efficacy. AM-tACS was applied via a two-electrode setup, attached on FpZ and below the right eye. AM-tACS waveforms comprised of different carrier (50 Hz, 200 Hz, 1000 Hz) and modulation frequencies (8 Hz, 16 Hz, 28 Hz) were administered with at maximum 2 mA peak-to-peak stimulation strength. TACS conditions in the same frequencies were used as a benchmark for phosphene induction. AM-tACS conditions using a 50 Hz carrier frequency were able to induce phosphenes, but with no difference in phosphene thresholds between modulation frequencies. AM-tACS using a 200 Hz or 1000 Hz carrier frequency did not induce phosphenes. TACS conditions induced phosphenes in line with previous studies. Stimulation effects of AM-tACS conditions were independent of amplitude modulation and instead relied solely on the carrier frequency. A possible explanation may be that AM-tACS needs higher stimulation intensities for its amplitude modulation to have a neuromodulatory effect.
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30
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Kreisberg E, Esmaeilpour Z, Adair D, Khadka N, Datta A, Badran BW, Bremner JD, Bikson M. High-resolution computational modeling of the current flow in the outer ear during transcutaneous auricular Vagus Nerve Stimulation (taVNS). Brain Stimul 2021; 14:1419-1430. [PMID: 34517143 PMCID: PMC8608747 DOI: 10.1016/j.brs.2021.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 09/07/2021] [Accepted: 09/09/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Transcutaneous auricular Vagus Nerve Stimulation (taVNS) applies low-intensity electrical current to the ear with the intention of activating the auricular branch of the Vagus nerve. The sensitivity and selectivity of stimulation applied to the ear depends on current flow pattern produced by a given electrode montage (size and placement). OBJECTIVE We compare different electrodes designs for taVNS considering both the predicted peak electric fields (sensitivity) and their spatial distribution (selectivity). METHODS Based on optimized high-resolution (0.47 mm) T1 and T2 weighted MRI, we developed an anatomical model of the left ear and the surrounding head tissues including brain, CSF/meninges, skull, muscle, blood vessels, fat, cartilage, and skin. The ear was further segmented into 6 regions of interest (ROI) based on various nerve densities: cavum concha, cymba concha, crus of helix, tragus, antitragus, and earlobe. A range of taVNS electrode montages were reproduced spanning varied electrodes sizes and placements over the tragus, cymba concha, earlobe, cavum concha, and crus of helix. Electric field across the ear (from superficial skin to cartilage) for each montage at 1 mA or 2 mA taVNS, assuming an activation threshold of 6.15 V/m, 12.3 V/m or 24.6 V/m was predicted using a Finite element method (FEM). Finally, considering every ROI, we calculated the sensitivity and selectivity of each montage. RESULTS Current flow patterns through the ear were highly specific to the electrode montage. Electric field was maximal at the ear regions directly under the electrodes, and for a given total current, increases with decreasing electrode size. Depending on the applied current and nerves threshold, activation may also occur in the regions between multiple anterior surface electrodes. Each considered montage was selective for one or two regions of interest. For example, electrodes across the tragus restricted significant electric field to the tragus. Stimulation across the earlobe restricted significant electric field to the earlobe and the antitragus. Because of this relative selectivity, use of control ear montages in experimental studies, support testing of targeting. Relative targeting was robust across assumptions of activation threshold and tissue properties. DISCUSSION Computational models provide additional insight on how details in electrode shape and placement impact sensitivity (how much current is needed) and selectivity (spatial distribution), thereby supporting analysis of existing approaches and optimization of new devices. Our result suggest taVNS current patterns and relative target are robust across individuals, though (variance in) axon morphology was not represented.
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Affiliation(s)
- Erica Kreisberg
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Zeinab Esmaeilpour
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Devin Adair
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Niranjan Khadka
- Department of Psychiatry, Division of Neuropsychiatry and Neuromodulation, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Abhishek Datta
- Research and Development, Soterix Medical, New York, USA, The City College of the City University of New York, New York, USA
| | - Bashar W Badran
- Department of Psychiatry, Medical University of South Carolina, Charleston, SC, USA
| | - J Douglas Bremner
- Departments of Psychiatry & Behavioral Sciences and Radiology, Emory University School of Medicine, And the Atlanta VA Medical Center, Decatur, Atlanta, GA, USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA.
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31
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Vasu SO, Kaphzan H. The role of sodium channels in direct current stimulation-axonal perspective. Cell Rep 2021; 37:109832. [PMID: 34644580 DOI: 10.1016/j.celrep.2021.109832] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 06/24/2021] [Accepted: 09/23/2021] [Indexed: 11/17/2022] Open
Abstract
Transcranial neurostimulation methods are utilized as therapies for various neuropsychiatric disorders. Primarily, they entail the delivery of weak subthreshold currents across the brain, which modulate neuronal excitability. However, it is still a puzzle how such weak electrical fields actuate their effects. Previous studies showed that axons are the most sensitive subcellular compartment for direct current stimulation, and maximal polarization is achieved at their terminals. Nonetheless, polarization of axon terminals according to models was predicted to be weak, and the mechanism for substantial axon terminals polarization was obscure. Here, we show that a weak subthreshold electrical field modifies the conductance of voltage-dependent sodium channels in axon terminals, subsequently amplifying their membrane polarization. Moreover, we show that this amplification has substantial effects on synaptic functioning. Finally, we employ analytical modeling to explain how sodium currents modifications enhance axon terminal polarization. These findings relate to the mechanistic aspects of any neurostimulation technique.
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Affiliation(s)
- Sreerag Othayoth Vasu
- Laboratory for Neurobiology of Psychiatric Disorders, Sagol Department of Neurobiology, University of Haifa, 199 Aba Khoushy Avenue, Mt. Carmel, 3498838 Haifa, Israel
| | - Hanoch Kaphzan
- Laboratory for Neurobiology of Psychiatric Disorders, Sagol Department of Neurobiology, University of Haifa, 199 Aba Khoushy Avenue, Mt. Carmel, 3498838 Haifa, Israel.
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32
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Lahogue C, Pinault D. Frontoparietal anodal tDCS reduces ketamine-induced oscillopathies. Transl Neurosci 2021; 12:282-296. [PMID: 34239718 PMCID: PMC8240415 DOI: 10.1515/tnsci-2020-0157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 05/05/2021] [Accepted: 05/14/2021] [Indexed: 12/26/2022] Open
Abstract
During the prodromal phase of schizophrenia with its complex and insidious clinical picture, electroencephalographic recordings detect widespread oscillation disturbances (or oscillopathies) during the wake-sleep cycle. Neural oscillations are electrobiomarkers of the connectivity state within systems. A single-systemic administration of ketamine, a non-competitive NMDA glutamate receptor antagonist, transiently reproduces the oscillopathies with a clinical picture reminiscent of the psychosis prodrome. This acute pharmacological model may help the research and development of innovative treatments against psychotic transition. Transcranial electrical stimulation is recognized as an appropriate non-invasive therapeutic modality since it can increase cognitive performance and modulate neural oscillations with little or no side effects. Therefore, our objective was to set up, in the sedated adult rat, a stimulation method that is able to normalize ketamine-induced increase in gamma-frequency (30-80 Hz) oscillations and decrease in sigma-frequency (10-17 Hz) oscillations. Unilateral and bipolar frontoparietal (FP), transcranial anodal stimulation by direct current (<+1 mA) was applied in ketamine-treated rats. A concomitant bilateral electroencephalographic recording of the parietal cortex measured the stimulation effects on its spontaneously occurring oscillations. A 5 min FP anodal tDCS immediately and quickly reduced, significantly with an intensity-effect relationship, the ketamine-induced gamma hyperactivity, and sigma hypoactivity at least in the bilateral parietal cortex. A duration effect was also recorded. The tDCS also tended to diminish the ketamine-induced delta hypoactivity. These preliminary neurophysiological findings are promising for developing a therapeutic proof-of-concept against neuropsychiatric disorders.
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Affiliation(s)
- Caroline Lahogue
- Université de Strasbourg, Strasbourg, France
- INSERM U1114, Neuropsychologie Cognitive et Physiopathologie de la Schizophrénie, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Centre de Recherche en Biomédecine de Strasbourg (CRBS), Faculté de médecine, Strasbourg, France
| | - Didier Pinault
- Université de Strasbourg, Strasbourg, France
- INSERM U1114, Neuropsychologie Cognitive et Physiopathologie de la Schizophrénie, Strasbourg, France
- Fédération de Médecine Translationnelle de Strasbourg (FMTS), Centre de Recherche en Biomédecine de Strasbourg (CRBS), Faculté de médecine, Strasbourg, France
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33
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Moreira A, Machado DGDS, Bikson M, Unal G, Bradley PS, Moscaleski L, Costa T, Kalil GCSG, Chao LW, Baptista AF, Morya E, Okano AH. Effect of Transcranial Direct Current Stimulation on Professional Female Soccer Players' Recovery Following Official Matches. Percept Mot Skills 2021; 128:1504-1529. [PMID: 34056967 DOI: 10.1177/00315125211021239] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This study investigated the effect of transcranial direct current stimulation (tDCS) combined with a recovery training session on the well-being and self-perceived recovery of professional female soccer players after official matches. Data from 13 world-class players were analyzed after participating in four official soccer matches of the first division of the Brazilian Women's Soccer Championship (7-, 10-, and 13-day intervals). We applied anodal tDCS (a-tDCS) over the left dorsolateral prefrontal cortex with 2 mA for 20 minutes (+F3/-F4 montage) the day after each match. Participants underwent two randomly ordered sessions of a-tDCS or sham. Players completed the Well-Being Questionnaire (WBQ) and the Total Quality Recovery (TQR) scale before each experimental condition and again the following morning. A two-way repeated-measures ANOVA showed a significant time x condition interaction on the WBQ (F(1,11)=5.21; p=0.043; ηp2=0.32), but not on the TQR (F(1,12) = 0.552; p = 0.47; ηp2 = 0.044). There was a large effect size (ES) for a-tDCS for the WBQ score (ES = 1.02; 95%CI = 0.17;1.88), and there was a moderate WBQ score increase (ES = 0.53; 95%CI = -0.29;1.34) for the sham condition. We found similar increases in the TQR score for a-tDCS (ES = 1.50; 95%CI = 0.63-2.37) and the sham condition (ES = 1.36; 95%CI = 0.51-2.22). These results suggest that a-tDCS (+F3/-F4 montage) combined with a recovery training session may slightly improve perceived well-being beyond the level of improvement after only the recovery training session among world-class female soccer players. Prior to widely adopting this recovery approach, further study is needed with larger and more diverse samples, including for female teams of different performance levels.
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Affiliation(s)
- Alexandre Moreira
- Department of Sport, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/ CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
| | - Daniel Gomes da Silva Machado
- Department of Physical Education, Federal University of Rio Grande do Norte, Natal, Brazil.,Graduate Program in Collective Health, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, New York, United States
| | - Gozde Unal
- Department of Biomedical Engineering, The City College of New York, New York, United States
| | - Paul S Bradley
- Research Institute of Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Luciane Moscaleski
- Center for Mathematics, Computation, and Cognition, Universidade Federal do ABC, São Bernardo do Campo, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/ CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
| | - Taline Costa
- Sports Medicine Department, Sport Clube Corinthians Paulista, São Paulo, Brazil
| | - Gabriella C S G Kalil
- Department of Sport, School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Liaw W Chao
- Centro de Acupuntura, Instituto de Ortopedia e Traumatologia - HCFMUSP, São Paulo, Brazil
| | - Abrahão F Baptista
- Center for Mathematics, Computation, and Cognition, Universidade Federal do ABC, São Bernardo do Campo, Brazil.,Laboratory of Medical Investigation 54 (LIM-54), Hospital das Clínicas, Faculdade de Medicina da USP, São Paulo, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/ CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
| | - Edgard Morya
- Edmond and Lily Safra International Institute of Neuroscience, Santos Dumont Institute, Rio Grande do Norte, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/ CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
| | - Alexandre H Okano
- Center for Mathematics, Computation, and Cognition, Universidade Federal do ABC, São Bernardo do Campo, Brazil.,Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/ CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
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Ranieri F, Mariotto S, Dubbioso R, Di Lazzaro V. Brain Stimulation as a Therapeutic Tool in Amyotrophic Lateral Sclerosis: Current Status and Interaction With Mechanisms of Altered Cortical Excitability. Front Neurol 2021; 11:605335. [PMID: 33613416 PMCID: PMC7892772 DOI: 10.3389/fneur.2020.605335] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/22/2020] [Indexed: 12/14/2022] Open
Abstract
In the last 20 years, several modalities of neuromodulation, mainly based on non-invasive brain stimulation (NIBS) techniques, have been tested as a non-pharmacological therapeutic approach to slow disease progression in amyotrophic lateral sclerosis (ALS). In both sporadic and familial ALS cases, neurophysiological studies point to motor cortical hyperexcitability as a possible priming factor in neurodegeneration, likely related to dysfunction of both excitatory and inhibitory mechanisms. A trans-synaptic anterograde mechanism of excitotoxicity is thus postulated, causing upper and lower motor neuron degeneration. Specifically, motor neuron hyperexcitability and hyperactivity are attributed to intrinsic cell abnormalities related to altered ion homeostasis and to impaired glutamate and gamma aminobutyric acid gamma-aminobutyric acid (GABA) signaling. Several neuropathological mechanisms support excitatory and synaptic dysfunction in ALS; additionally, hyperexcitability seems to drive DNA-binding protein 43-kDA (TDP-43) pathology, through the upregulation of unusual isoforms directly contributing to ASL pathophysiology. Corticospinal excitability can be suppressed or enhanced using NIBS techniques, namely, repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), as well as invasive brain and spinal stimulation. Experimental evidence supports the hypothesis that the after-effects of NIBS are mediated by long-term potentiation (LTP)-/long-term depression (LTD)-like mechanisms of modulation of synaptic activity, with different biological and physiological mechanisms underlying the effects of tDCS and rTMS and, possibly, of different rTMS protocols. This potential has led to several small trials testing different stimulation interventions to antagonize excitotoxicity in ALS. Overall, these studies suggest a possible efficacy of neuromodulation in determining a slight reduction of disease progression, related to the type, duration, and frequency of treatment, but current evidence remains preliminary. Main limitations are the small number and heterogeneity of recruited patients, the limited "dosage" of brain stimulation that can be delivered in the hospital setting, the lack of a sufficient knowledge on the excitatory and inhibitory mechanisms targeted by specific stimulation interventions, and the persistent uncertainty on the key pathophysiological processes leading to motor neuron loss. The present review article provides an update on the state of the art of neuromodulation in ALS and a critical appraisal of the rationale for the application/optimization of brain stimulation interventions, in the light of their interaction with ALS pathophysiological mechanisms.
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Affiliation(s)
- Federico Ranieri
- Neurology Unit, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Sara Mariotto
- Neurology Unit, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Raffaele Dubbioso
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples “Federico II”, Naples, Italy
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Campus Bio-Medico University, Rome, Italy
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Sánchez-León CA, Cordones I, Ammann C, Ausín JM, Gómez-Climent MA, Carretero-Guillén A, Sánchez-Garrido Campos G, Gruart A, Delgado-García JM, Cheron G, Medina JF, Márquez-Ruiz J. Immediate and after effects of transcranial direct-current stimulation in the mouse primary somatosensory cortex. Sci Rep 2021; 11:3123. [PMID: 33542338 PMCID: PMC7862679 DOI: 10.1038/s41598-021-82364-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/24/2020] [Indexed: 01/30/2023] Open
Abstract
Transcranial direct-current stimulation (tDCS) is a non-invasive brain stimulation technique consisting in the application of weak electric currents on the scalp. Although previous studies have demonstrated the clinical value of tDCS for modulating sensory, motor, and cognitive functions, there are still huge gaps in the knowledge of the underlying physiological mechanisms. To define the immediate impact as well as the after effects of tDCS on sensory processing, we first performed electrophysiological recordings in primary somatosensory cortex (S1) of alert mice during and after administration of S1-tDCS, and followed up with immunohistochemical analysis of the stimulated brain regions. During the application of cathodal and anodal transcranial currents we observed polarity-specific bidirectional changes in the N1 component of the sensory-evoked potentials (SEPs) and associated gamma oscillations. On the other hand, 20 min of cathodal stimulation produced significant after-effects including a decreased SEP amplitude for up to 30 min, a power reduction in the 20-80 Hz range and a decrease in gamma event related synchronization (ERS). In contrast, no significant changes in SEP amplitude or power analysis were observed after anodal stimulation except for a significant increase in gamma ERS after tDCS cessation. The polarity-specific differences of these after effects were corroborated by immunohistochemical analysis, which revealed an unbalance of GAD 65-67 immunoreactivity between the stimulated versus non-stimulated S1 region only after cathodal tDCS. These results highlight the differences between immediate and after effects of tDCS, as well as the asymmetric after effects induced by anodal and cathodal stimulation.
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Affiliation(s)
- Carlos A. Sánchez-León
- grid.15449.3d0000 0001 2200 2355Department of Physiology, Anatomy and Cell Biology, Pablo de Olavide University, Ctra. de Utrera, km. 1, 41013 Seville, Spain
| | - Isabel Cordones
- grid.15449.3d0000 0001 2200 2355Department of Physiology, Anatomy and Cell Biology, Pablo de Olavide University, Ctra. de Utrera, km. 1, 41013 Seville, Spain
| | - Claudia Ammann
- grid.428486.40000 0004 5894 9315HM CINAC, Hospital Universitario HM Puerta del Sur, HM Hospitales, Madrid, Spain
| | - José M. Ausín
- grid.157927.f0000 0004 1770 5832Instituto de Investigación E Innovación en Bioingeniería, Universidad Politécnica de Valencia, Valencia, Spain
| | - María A. Gómez-Climent
- grid.15449.3d0000 0001 2200 2355Department of Physiology, Anatomy and Cell Biology, Pablo de Olavide University, Ctra. de Utrera, km. 1, 41013 Seville, Spain
| | - Alejandro Carretero-Guillén
- grid.15449.3d0000 0001 2200 2355Department of Physiology, Anatomy and Cell Biology, Pablo de Olavide University, Ctra. de Utrera, km. 1, 41013 Seville, Spain
| | - Guillermo Sánchez-Garrido Campos
- grid.15449.3d0000 0001 2200 2355Department of Physiology, Anatomy and Cell Biology, Pablo de Olavide University, Ctra. de Utrera, km. 1, 41013 Seville, Spain
| | - Agnès Gruart
- grid.15449.3d0000 0001 2200 2355Department of Physiology, Anatomy and Cell Biology, Pablo de Olavide University, Ctra. de Utrera, km. 1, 41013 Seville, Spain
| | - José M. Delgado-García
- grid.15449.3d0000 0001 2200 2355Department of Physiology, Anatomy and Cell Biology, Pablo de Olavide University, Ctra. de Utrera, km. 1, 41013 Seville, Spain
| | - Guy Cheron
- grid.8364.90000 0001 2184 581XLaboratory of Electrophysiology, Université de Mons, Mons, Belgium ,grid.4989.c0000 0001 2348 0746Laboratory of Neurophysiology and Movement Biomechanics, ULB Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium
| | - Javier F. Medina
- grid.39382.330000 0001 2160 926XDepartment of Neuroscience, Baylor College of Medicine, Houston, TX USA
| | - Javier Márquez-Ruiz
- grid.15449.3d0000 0001 2200 2355Department of Physiology, Anatomy and Cell Biology, Pablo de Olavide University, Ctra. de Utrera, km. 1, 41013 Seville, Spain
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van Boekholdt L, Kerstens S, Khatoun A, Asamoah B, Mc Laughlin M. tDCS peripheral nerve stimulation: a neglected mode of action? Mol Psychiatry 2021; 26:456-461. [PMID: 33299136 DOI: 10.1038/s41380-020-00962-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/19/2020] [Accepted: 11/16/2020] [Indexed: 11/09/2022]
Abstract
Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation method widely used by neuroscientists and clinicians for research and therapeutic purposes. tDCS is currently under investigation as a treatment for a range of psychiatric disorders. Despite its popularity, a full understanding of tDCS's underlying neurophysiological mechanisms is still lacking. tDCS creates a weak electric field in the cerebral cortex which is generally assumed to cause the observed effects. Interestingly, as tDCS is applied directly on the skin, localized peripheral nerve endings are exposed to much higher electric field strengths than the underlying cortices. Yet, the potential contribution of peripheral mechanisms in causing tDCS's effects has never been systemically investigated. We hypothesize that tDCS induces arousal and vigilance through peripheral mechanisms. We suggest that this may involve peripherally-evoked activation of the ascending reticular activating system, in which norepinephrine is distributed throughout the brain by the locus coeruleus. Finally, we provide suggestions to improve tDCS experimental design beyond the standard sham control, such as topical anesthetics to block peripheral nerves and active controls to stimulate non-target areas. Broad adoption of these measures in all tDCS experiments could help disambiguate peripheral from true transcranial tDCS mechanisms.
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Affiliation(s)
- Luuk van Boekholdt
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Silke Kerstens
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Ahmad Khatoun
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Boateng Asamoah
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Myles Mc Laughlin
- Exp ORL, Department of Neuroscience, Leuven Brain Institute, KU Leuven, Leuven, Belgium.
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Garcia S, Hampstead BM. HD-tDCS as a neurorehabilitation technique for a case of post-anoxic leukoencephalopathy. Neuropsychol Rehabil 2020; 32:946-966. [PMID: 33208043 DOI: 10.1080/09602011.2020.1845749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Post-anoxic leukoencephalopathy is a rare event that causes global demyelination secondary to anoxic injury. Given the nature and extent of the damage, cognitive and functional deficits are typically chronic even after standard therapies. Here, we describe a novel treatment approach that used high definition transcranial direct-current stimulation (HD-tDCS) with a 62-year-old male who was 5 years post-anoxic leukoencephalopathy secondary to an accidental drug overdose. HD-tDCS was administered over the left lateral prefrontal cortex across 29 daily sessions at 2 mA (20 min/session) in order to address dysexecutive behaviors. Results demonstrated improved delayed memory and trends for improved visuospatial and semantic fluency performance as well as improved insight and daily functioning, all of which returned to baseline by the end of a 10 week no-contact follow up period. Resting state fMRI connectivity results mirrored these changes by showing increased dorsal attention and cingulo-opercular but reduced ventral attention network connectivity after session 29, all of which returned to baseline at follow-up. These findings suggest HD-tDCS may benefit functioning even following serious and pervasive anoxic injury. Findings also suggest the need for continued HD-tDCS for maintenance purposes, though future work is needed to identify optimal dose-response information.
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Affiliation(s)
- Sarah Garcia
- Psychology Department, Stetson University, DeLand, FL, USA
| | - Benjamin M Hampstead
- Mental Health Service, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.,Research Program on Cognition and Neuromodulation Based Interventions, Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
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Esmaeilpour Z, Kronberg G, Reato D, Parra LC, Bikson M. Temporal interference stimulation targets deep brain regions by modulating neural oscillations. Brain Stimul 2020; 14:55-65. [PMID: 33186778 PMCID: PMC9382891 DOI: 10.1016/j.brs.2020.11.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 11/06/2020] [Accepted: 11/07/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Temporal interference (TI) stimulation of the brain generates amplitude-modulated electric fields oscillating in the kHz range with the goal of non-invasive targeted deep brain stimulation. Yet, the current intensities required in human (sensitivity) to modulate deep brain activity and if superficial brain region are spared (selectivity) at these intensities remains unclear. OBJECTIVE We developed an experimentally constrained theory for TI sensitivity to kHz electric field given the attenuation by membrane low-pass filtering property, and for TI selectivity to deep structures given the distribution of modulated and unmodulated electric fields in brain. METHODS The electric field threshold to modulate carbachol-induced gamma oscillations in rat hippocampal slices was determined for unmodulated 0.05-2 kHz sine waveforms, and 5 Hz amplitude-modulated waveforms with 0.1-2 kHz carrier frequencies. The neuronal effects are replicated with a computational network model to explore the underlying mechanisms, and then coupled to a validated current-flow model of the human head. RESULTS Amplitude-modulated electric fields are stronger in deep brain regions, while unmodulated electric fields are maximal at the cortical regions. Both experiment and model confirmed the hypothesis that spatial selectivity of temporal interference stimulation depends on the phasic modulation of neural oscillations only in deep brain regions. Adaptation mechanism (e.g. GABAb) enhanced sensitivity to amplitude modulated waveform in contrast to unmodulated kHz and produced selectivity in modulating gamma oscillation (i.e. Higher gamma modulation in amplitude modulated vs unmodulated kHz stimulation). Selection of carrier frequency strongly affected sensitivity to amplitude modulation stimulation. Amplitude modulated stimulation with 100 Hz carrier frequency required ∼5 V/m (corresponding to ∼13 mA at the scalp surface), whereas, 1 kHz carrier frequency ∼60 V/m (∼160 mA) and 2 kHz carrier frequency ∼80 V/m (∼220 mA) to significantly modulate gamma oscillation. Sensitivity is increased (scalp current required decreased) for theoretical neuronal membranes with faster time constants. CONCLUSION The TI sensitivity (current required at the scalp) depends on the neuronal membrane time-constant (e.g. axons) approaching the kHz carrier frequency. TI selectivity is governed by network adaption (e.g. GABAb) that is faster than the amplitude-modulation frequency. Thus, we show neuronal and network oscillations time-constants determine the scalp current required and the selectivity achievable with TI in humans.
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Affiliation(s)
- Zeinab Esmaeilpour
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA.
| | - Greg Kronberg
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA
| | - Davide Reato
- Champalimaud Centre for the Unknown, Neuroscience Program, Lisbon, Portugal
| | - Lucas C Parra
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of the City University of New York, New York, NY, USA
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39
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Mirzakhalili E, Barra B, Capogrosso M, Lempka SF. Biophysics of Temporal Interference Stimulation. Cell Syst 2020; 11:557-572.e5. [PMID: 33157010 DOI: 10.1016/j.cels.2020.10.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/21/2020] [Accepted: 10/06/2020] [Indexed: 02/06/2023]
Abstract
Temporal interference (TI) is a non-invasive neurostimulation technique that utilizes high-frequency external electric fields to stimulate deep neuronal structures without affecting superficial, off-target structures. TI represents a potential breakthrough for treating conditions, such as Parkinson's disease and chronic pain. However, early clinical work on TI stimulation was met with mixed outcomes challenging its fundamental mechanisms and applications. Here, we apply established physics to study the mechanisms of TI with the goal of optimizing it for clinical use. We argue that TI stimulation cannot work via passive membrane filtering, as previously hypothesized. Instead, TI stimulation requires an ion-channel mediated signal rectification process. Unfortunately, this mechanism is also responsible for high-frequency conduction block in off-target tissues, thus challenging clinical applications of TI. In consequence, we propose a set of experimental controls that should be performed in future experiments to refine our understanding and practice of TI stimulation. A record of this paper's transparent peer review process is included in the Supplemental Information.
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Affiliation(s)
- Ehsan Mirzakhalili
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Beatrice Barra
- Department of Neuroscience and Movement Science, University of Fribourg, Fribourg, Switzerland; Rehab and Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Marco Capogrosso
- Rehab and Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA.
| | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Anesthesiology, University of Michigan, Ann Arbor, MI 48109, USA.
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40
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Modulation of solute diffusivity in brain tissue as a novel mechanism of transcranial direct current stimulation (tDCS). Sci Rep 2020; 10:18488. [PMID: 33116214 PMCID: PMC7595173 DOI: 10.1038/s41598-020-75460-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/13/2020] [Indexed: 12/17/2022] Open
Abstract
The breadth of brain disorders and functions reported responsive to transcranial direct current stimulation (tDCS) suggests a generalizable mechanism of action. Prior efforts characterized its cellular targets including neuron, glia and endothelial cells. We propose tDCS also modulates the substance transport in brain tissue. High resolution multiphoton microscopy imaged the spread across rat brain tissue of fluorescently-labeled solutes injected through the carotid artery after tDCS. The effective solute diffusion coefficient of brain tissue (Deff) was determined from the spatio-temporal solute concentration profiles using an unsteady diffusion transport model. 5–10 min post 20 min–1 mA tDCS, Deff increased by ~ 10% for a small solute, sodium fluorescein, and ~ 120% for larger solutes, BSA and Dex-70k. All increases in Deff returned to the control level 25–30 min post tDCS. A mathematical model for Deff in the extracelluar space (ECS) further predicts that this dose of tDCS increases Deff by transiently enhancing the brain ECS gap spacing by ~ 1.5-fold and accordingly reducing the extracellular matrix density. The cascades leading ECS modulation and its impact on excitability, synaptic function, plasticity, and brain clearance require further study. Modulation of solute diffusivity and ECS could explain diverse outcomes of tDCS and suggest novel therapeutic strategies.
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Bower KL, McIntyre CC. Deep brain stimulation of terminating axons. Brain Stimul 2020; 13:1863-1870. [PMID: 32919091 DOI: 10.1016/j.brs.2020.09.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/05/2020] [Accepted: 09/01/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Deep brain stimulation (DBS) of the subthalamic region is an established treatment for the motor symptoms of Parkinson's disease. Several types of neural elements reside in the subthalamic region, including subthalamic nucleus (STN) neurons, fibers of passage, and terminating afferents. Recent studies suggest that direct activation of a specific population of subthalamic afferents, known as the hyperdirect pathway, may be responsible for some of the therapeutic effects of subthalamic DBS. OBJECTIVE The goal of this study was to quantify how axon termination affects neural excitability from DBS. We evaluated how adjusting different stimulation parameters influenced the relative excitability of terminating axons (TAs) compared to fibers of passage (FOPs). METHODS We used finite element electric field models of DBS, coupled to multi-compartment cable models of axons, to calculate activation thresholds for populations of TAs and FOPs. These generalized models were used to evaluate the response to anodic vs. cathodic stimulation, with short vs. long stimulus pulses. RESULTS Terminating axons generally exhibited lower thresholds than fibers of passage across all tested parameters. Short pulse widths accentuated the relative excitability of TAs over FOPs. CONCLUSION(S) Our computational results demonstrate a hyperexcitability of terminating axons to DBS that is robust to variation in the stimulation parameters, as well as the axon model parameters.
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Affiliation(s)
- Kelsey L Bower
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Cameron C McIntyre
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
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Cheng C, Aplin FP, Fridman GY. A microfluidic system integrated with shape memory alloy valves for a safe direct current delivery system. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:3544-3548. [PMID: 33018768 DOI: 10.1109/embc44109.2020.9176474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Direct current (DC) has potential as a clinical and scientific tool to accelerate wound healing, increase the permeability of the skin to drug treatment and modulate neural activity. But long duration delivery of DC unavoidably causes hazardous electrolysis at the tissue-electrode interface. To be able to deliver long duration DC, we previously proposed a design for a safe direct current stimulator (SDCS). This device uses alternating current that does not cause chemical reactions at the metal electrodes within the device, but delivers ionic direct current output to the tissue via microfluidic valves. We previously developed and published designs of multiple SDCS components including microfluidic, electronic, data processing, and energy systems. In this paper we focus on the development of the integrated microfluidics needed by the SDCS system. We developed a fabrication method and characterized valve performance within the multi-valve microfluidic system. We used poly-dimethylsiloxane (PDMS) to fabricate three microfluidic chips that integrated valves actuated by 50-µm Nitinol (NiTi) shape memory alloy (SMA) wire. We tested system operation by driving SMA valves with a current pulse and recording the valve response with an electrical assay. The valve operation complied with the SDCS system requirements. The time for valves to open was rapid at 0.177 ± 0.04 seconds, and the time for the valves to close was 0.265 ± 0.05 seconds. Open microfluidic channel impedance for unrestricted ionic current flow was 15.90 ± 8.28 kΩ and it increased by a factor of 40 to restrict ionic current flow at 678 ± 102 kΩ for the closed valves.
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43
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Steadman CJ, Grill WM. Spinal cord stimulation for the restoration of bladder function after spinal cord injury. Healthc Technol Lett 2020; 7:87-92. [PMID: 32754343 PMCID: PMC7353924 DOI: 10.1049/htl.2020.0026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 05/15/2020] [Accepted: 05/15/2020] [Indexed: 12/20/2022] Open
Abstract
Spinal cord injury (SCI) results in the inability to empty the bladder voluntarily, and neurogenic detrusor overactivity (NDO) and detrusor sphincter dyssynergia (DSD) negatively impact both the health and quality of life of persons with SCI. Current approaches to treat bladder dysfunction in persons with SCI, including self-catheterisation and anticholinergic medications, are inadequate, and novel approaches are required to restore continence with increased bladder capacity, as well as to provide predictable and efficient on-demand voiding. Improvements in bladder function following SCI have been documented using a number of different modalities of spinal cord stimulation (SCS) in both persons with SCI and animal models, including SCS alone or SCS with concomitant activity-based training. Improvements include increased volitional voiding, voided volumes, bladder capacity, and quality of life, as well as decreases in NDO and DSD. Further, SCS is a well-developed therapy for chronic pain, and existing Food And Drug Administration (FDA)-approved devices provide a clear pathway to sustainable commercial availability and impact. However, the effective stimulation parameters and the appropriate timing and location of stimulation for SCS-mediated restoration of bladder function require further study, and studies are needed to determine underlying mechanisms of action.
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Affiliation(s)
- Casey J Steadman
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.,Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, USA.,Department of Neurobiology, Duke University, Durham, NC 27708, USA.,Department of Neurosurgery, Duke University, Durham, NC 27708, USA
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Transcranial electrical stimulation motor threshold can estimate individualized tDCS dosage from reverse-calculation electric-field modeling. Brain Stimul 2020; 13:961-969. [PMID: 32330607 PMCID: PMC7906246 DOI: 10.1016/j.brs.2020.04.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 12/15/2022] Open
Abstract
Background: Unique amongst brain stimulation tools, transcranial direct current stimulation (tDCS) currently lacks an easy or widely implemented method for individualizing dosage. Objective: We developed a method of reverse-calculating electric-field (E-field) models based on Magnetic Resonance Imaging (MRI) scans that can estimate individualized tDCS dose. We also evaluated an MRI-free method of individualizing tDCS dose by measuring transcranial magnetic stimulation (TMS) motor threshold (MT) and single pulse, suprathreshold transcranial electrical stimulation (TES) MT and regressing it against E-field modeling. Key assumptions of reverse-calculation E-field modeling, including the size of region of interest (ROI) analysis and the linearity of multiple E-field models were also tested. Methods: In 29 healthy adults, we acquired TMS MT, TES MT, and anatomical T1-weighted MPRAGE MRI scans with a fiducial marking the motor hotspot. We then computed a “reverse-calculated tDCS dose” of tDCS applied at the scalp needed to cause a 1.00 V/m E-field at the cortex. Finally, we examined whether the predicted E-field values correlated with each participant’s measured TMS MT or TES MT. Results: We were able to determine a reverse-calculated tDCS dose for each participant using a 5 × 5 x 5 voxel grid region of interest (ROI) approach (average = 6.03 mA, SD = 1.44 mA, range = 3.75–9.74 mA). The Transcranial Electrical Stimulation MT, but not the Transcranial Magnetic Stimulation MT, significantly correlated with the ROI-based reverse-calculated tDCS dose determined by E-field modeling (R2 = 0.45, p < 0.001). Conclusions: Reverse-calculation E-field modeling, alone or regressed against TES MT, shows promise as a method to individualize tDCS dose. The large range of the reverse-calculated tDCS doses between subjects underscores the likely need to individualize tDCS dose. Future research should further examine the use of TES MT to individually dose tDCS as an MRI-free method of dosing tDCS.
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Howell B, McIntyre CC. Feasibility of Interferential and Pulsed Transcranial Electrical Stimulation for Neuromodulation at the Human Scale. Neuromodulation 2020; 24:843-853. [PMID: 32147953 DOI: 10.1111/ner.13137] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/06/2020] [Accepted: 02/13/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVES Transcranial electrical stimulation (tES) is a promising tool for modulating neural activity, but tES has poor penetrability and spatiotemporal resolution compared to invasive techniques like deep brain stimulation (DBS). Interferential strategies for alternating-current stimulation (IF-tACS) and pulsed/intersectional strategies for transcranial direct-current stimulation (IS-tDCS) address some of the limitations of tES, but the comparative advantages and disadvantages of these new techniques is not well understood. This study's objective was to evaluate the suprathreshold and subthreshold membrane dynamics of neurons in response to IF-tACS and IS-tDCS. MATERIALS AND METHODS We analyzed the biophysics of IF-tACS and IS-tDCS using a bioelectric field model of tES. Neural responses were quantified for suprathreshold generation of action potentials in axons and for subthreshold modulation of membrane dynamics in spiking pyramidal neurons. RESULTS IF-tACS and IS-tDCS could not directly activate axons at or below 10 mA, but within this current range, these fields were able to modulate, albeit indirectly, spiking activity in the neuron model. IF-tACS facilitated phase synchronization similar to tACS, and IS-tDCS enhanced and suppressed spiking activity similar to tDCS; however, in either case, the modulatory effects of these fields were less potent than their standard counterparts at a matched field intensity. Moreover, neither IF-tACS nor IS-tDCS improved the spatial selectivity of their parent strategies. CONCLUSIONS Enhancing the spatiotemporal precision and penetrability of tES with interferential and intersectional strategies is possible at the human scale. However, IF-tACS or IS-tDCS will likely require spatial multiplexing with multiple simultaneous sources to counteract their reduced potency, compared to standard techniques, to maintain stimulation currents at tolerable levels.
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Affiliation(s)
- Bryan Howell
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Cameron C McIntyre
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
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Kronberg G, Rahman A, Sharma M, Bikson M, Parra LC. Direct current stimulation boosts hebbian plasticity in vitro. Brain Stimul 2020; 13:287-301. [PMID: 31668982 PMCID: PMC6989352 DOI: 10.1016/j.brs.2019.10.014] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 09/10/2019] [Accepted: 10/16/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND There is evidence that transcranial direct current stimulation (tDCS) can improve learning performance. Arguably, this effect is related to long term potentiation (LTP), but the precise biophysical mechanisms remain unknown. HYPOTHESIS We propose that direct current stimulation (DCS) causes small changes in postsynaptic membrane potential during ongoing endogenous synaptic activity. The altered voltage dynamics in the postsynaptic neuron then modify synaptic strength via the machinery of endogenous voltage-dependent Hebbian plasticity. This hypothesis predicts that DCS should exhibit Hebbian properties, namely pathway specificity and associativity. METHODS We studied the effects of DCS applied during the induction of LTP in the CA1 region of rat hippocampal slices and using a biophysical computational model. RESULTS DCS enhanced LTP, but only at synapses that were undergoing plasticity, confirming that DCS respects Hebbian pathway specificity. When different synaptic pathways cooperated to produce LTP, DCS enhanced this cooperation, boosting Hebbian associativity. Further slice experiments and computer simulations support a model where polarization of postsynaptic pyramidal neurons drives these plasticity effects through endogenous Hebbian mechanisms. The model is able to reconcile several experimental results by capturing the complex interaction between the induced electric field, neuron morphology, and endogenous neural activity. CONCLUSIONS These results suggest that tDCS can enhance associative learning. We propose that clinical tDCS should be applied during tasks that induce Hebbian plasticity to harness this phenomenon, and that the effects should be task specific through their interaction with endogenous plasticity mechanisms. Models that incorporate brain state and plasticity mechanisms may help to improve prediction of tDCS outcomes.
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Affiliation(s)
- Greg Kronberg
- Department of Biomedical Engineering, The City College of New York, CUNY, 160 Convent Avenue, New York, NY, USA.
| | - Asif Rahman
- Department of Biomedical Engineering, The City College of New York, CUNY, 160 Convent Avenue, New York, NY, USA
| | - Mahima Sharma
- Department of Biomedical Engineering, The City College of New York, CUNY, 160 Convent Avenue, New York, NY, USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, CUNY, 160 Convent Avenue, New York, NY, USA
| | - Lucas C Parra
- Department of Biomedical Engineering, The City College of New York, CUNY, 160 Convent Avenue, New York, NY, USA
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Bikson M, Dmochowski J. What it means to go deep with non-invasive brain stimulation. Clin Neurophysiol 2019; 131:752-754. [PMID: 31917081 DOI: 10.1016/j.clinph.2019.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 12/14/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Marom Bikson
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States.
| | - Jacek Dmochowski
- Department of Biomedical Engineering, The City College of New York, New York, NY, United States
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Manca M, Glowatzki E, Roberts DC, Fridman GY, Aplin FP. Ionic direct current modulation evokes spike-rate adaptation in the vestibular periphery. Sci Rep 2019; 9:18924. [PMID: 31831760 PMCID: PMC6908704 DOI: 10.1038/s41598-019-55045-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 11/20/2019] [Indexed: 12/28/2022] Open
Abstract
Recent studies have shown that ionic direct current (iDC) can modulate the vestibular system in-vivo, with potential benefits over conventional pulsed stimulation. In this study, the effects of iDC stimulation on vestibular nerve fiber firing rate was investigated using loose-patch nerve fiber recordings in the acutely excised mouse crista ampullaris of the semicircular canals. Cathodic and anodic iDC steps instantaneously reduced and increased afferent spike rate, with the polarity of this effect dependent on the position of the stimulating electrode. A sustained constant anodic or cathodic current resulted in an adaptation to the stimulus and a return to spontaneous spike rate. Post-adaptation spike rate responses to iDC steps were similar to pre-adaptation controls. At high intensities spike rate response sensitivities were modified by the presence of an adaptation step. Benefits previously observed in behavioral responses to iDC steps delivered after sustained current may be due to post-adaptation changes in afferent sensitivity. These results contribute to an understanding of peripheral spike rate relationships for iDC vestibular stimulation and validate an ex-vivo model for future investigation of cellular mechanisms. In conjunction with previous in-vivo studies, these data help to characterize iDC stimulation as a potential therapy to restore vestibular function after bilateral vestibulopathy.
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Affiliation(s)
- Marco Manca
- Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland, 21205, United States
| | - Elisabeth Glowatzki
- Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland, 21205, United States.,Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland, 21205, United States
| | - Dale C Roberts
- Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland, 21205, United States
| | - Gene Y Fridman
- Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland, 21205, United States. .,Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, 21205, United States. .,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, 21205, United States.
| | - Felix P Aplin
- Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University, Baltimore, Maryland, 21205, United States
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Morya E, Monte-Silva K, Bikson M, Esmaeilpour Z, Biazoli CE, Fonseca A, Bocci T, Farzan F, Chatterjee R, Hausdorff JM, da Silva Machado DG, Brunoni AR, Mezger E, Moscaleski LA, Pegado R, Sato JR, Caetano MS, Sá KN, Tanaka C, Li LM, Baptista AF, Okano AH. Beyond the target area: an integrative view of tDCS-induced motor cortex modulation in patients and athletes. J Neuroeng Rehabil 2019; 16:141. [PMID: 31730494 PMCID: PMC6858746 DOI: 10.1186/s12984-019-0581-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 08/19/2019] [Indexed: 02/07/2023] Open
Abstract
Transcranial Direct Current Stimulation (tDCS) is a non-invasive technique used to modulate neural tissue. Neuromodulation apparently improves cognitive functions in several neurologic diseases treatment and sports performance. In this study, we present a comprehensive, integrative review of tDCS for motor rehabilitation and motor learning in healthy individuals, athletes and multiple neurologic and neuropsychiatric conditions. We also report on neuromodulation mechanisms, main applications, current knowledge including areas such as language, embodied cognition, functional and social aspects, and future directions. We present the use and perspectives of new developments in tDCS technology, namely high-definition tDCS (HD-tDCS) which promises to overcome one of the main tDCS limitation (i.e., low focality) and its application for neurological disease, pain relief, and motor learning/rehabilitation. Finally, we provided information regarding the Transcutaneous Spinal Direct Current Stimulation (tsDCS) in clinical applications, Cerebellar tDCS (ctDCS) and its influence on motor learning, and TMS combined with electroencephalography (EEG) as a tool to evaluate tDCS effects on brain function.
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Affiliation(s)
- Edgard Morya
- Edmond and Lily Safra International Institute of Neuroscience, Santos Dumont Institute, Macaíba, Rio Grande do Norte Brazil
- Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
| | - Kátia Monte-Silva
- Universidade Federal de Pernambuco, Recife, Pernambuco Brazil
- Núcleo de Assistência e Pesquisa em Neuromodulação (NAPeN), Universidade Federal do ABC (UFABC)/Universidade de São Paulo (USP)/Universidade Cidade de São Paulo (UNICID)/Universidade Federal de Pernambuco (UFPE), Escola Bahiana de Medicina e Saúde Pública (EBMSP), Santo André, Brazil
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York of CUNY, New York, NY USA
| | - Zeinab Esmaeilpour
- Department of Biomedical Engineering, The City College of New York of CUNY, New York, NY USA
| | - Claudinei Eduardo Biazoli
- Center of Mathematics, Computing and Cognition (CMCC), Universidade Federal do ABC (UFABC), Alameda da Universidade, 3 - Anchieta, Bloco Delta – Sala 257, São Bernardo do Campo, SP CEP 09606-070 Brazil
| | - Andre Fonseca
- Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
- Center of Mathematics, Computing and Cognition (CMCC), Universidade Federal do ABC (UFABC), Alameda da Universidade, 3 - Anchieta, Bloco Delta – Sala 257, São Bernardo do Campo, SP CEP 09606-070 Brazil
| | - Tommaso Bocci
- Aldo Ravelli Center for Neurotechnology and Experimental Brain Therapeutics, Department of Health Sciences, International Medical School, University of Milan, Milan, Italy
| | - Faranak Farzan
- School of Mechatronic Systems Engineering, Simon Fraser University, Surrey, British Columbia Canada
| | - Raaj Chatterjee
- School of Mechatronic Systems Engineering, Simon Fraser University, Surrey, British Columbia Canada
| | - Jeffrey M. Hausdorff
- Department of Physical Therapy, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | | | | | - Eva Mezger
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany
| | - Luciane Aparecida Moscaleski
- Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
- Center of Mathematics, Computing and Cognition (CMCC), Universidade Federal do ABC (UFABC), Alameda da Universidade, 3 - Anchieta, Bloco Delta – Sala 257, São Bernardo do Campo, SP CEP 09606-070 Brazil
| | - Rodrigo Pegado
- Graduate Program in Rehabilitation Science, Universidade Federal do Rio Grande do Norte, Santa Cruz, Rio Grande do Norte Brazil
| | - João Ricardo Sato
- Center of Mathematics, Computing and Cognition (CMCC), Universidade Federal do ABC (UFABC), Alameda da Universidade, 3 - Anchieta, Bloco Delta – Sala 257, São Bernardo do Campo, SP CEP 09606-070 Brazil
| | - Marcelo Salvador Caetano
- Center of Mathematics, Computing and Cognition (CMCC), Universidade Federal do ABC (UFABC), Alameda da Universidade, 3 - Anchieta, Bloco Delta – Sala 257, São Bernardo do Campo, SP CEP 09606-070 Brazil
| | - Kátia Nunes Sá
- Núcleo de Assistência e Pesquisa em Neuromodulação (NAPeN), Universidade Federal do ABC (UFABC)/Universidade de São Paulo (USP)/Universidade Cidade de São Paulo (UNICID)/Universidade Federal de Pernambuco (UFPE), Escola Bahiana de Medicina e Saúde Pública (EBMSP), Santo André, Brazil
- Escola Bahiana de Medicina e Saúde Pública, Salvador, Bahia Brazil
| | - Clarice Tanaka
- Núcleo de Assistência e Pesquisa em Neuromodulação (NAPeN), Universidade Federal do ABC (UFABC)/Universidade de São Paulo (USP)/Universidade Cidade de São Paulo (UNICID)/Universidade Federal de Pernambuco (UFPE), Escola Bahiana de Medicina e Saúde Pública (EBMSP), Santo André, Brazil
- Laboratório de Investigações Médicas-54, Universidade de São Paulo, São Paulo, São Paulo Brazil
| | - Li Min Li
- Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
| | - Abrahão Fontes Baptista
- Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
- Núcleo de Assistência e Pesquisa em Neuromodulação (NAPeN), Universidade Federal do ABC (UFABC)/Universidade de São Paulo (USP)/Universidade Cidade de São Paulo (UNICID)/Universidade Federal de Pernambuco (UFPE), Escola Bahiana de Medicina e Saúde Pública (EBMSP), Santo André, Brazil
- Center of Mathematics, Computing and Cognition (CMCC), Universidade Federal do ABC (UFABC), Alameda da Universidade, 3 - Anchieta, Bloco Delta – Sala 257, São Bernardo do Campo, SP CEP 09606-070 Brazil
- Escola Bahiana de Medicina e Saúde Pública, Salvador, Bahia Brazil
- Laboratório de Investigações Médicas-54, Universidade de São Paulo, São Paulo, São Paulo Brazil
| | - Alexandre Hideki Okano
- Brazilian Institute of Neuroscience and Neurotechnology (BRAINN/CEPID-FAPESP), University of Campinas, Campinas, São Paulo, Brazil
- Núcleo de Assistência e Pesquisa em Neuromodulação (NAPeN), Universidade Federal do ABC (UFABC)/Universidade de São Paulo (USP)/Universidade Cidade de São Paulo (UNICID)/Universidade Federal de Pernambuco (UFPE), Escola Bahiana de Medicina e Saúde Pública (EBMSP), Santo André, Brazil
- Center of Mathematics, Computing and Cognition (CMCC), Universidade Federal do ABC (UFABC), Alameda da Universidade, 3 - Anchieta, Bloco Delta – Sala 257, São Bernardo do Campo, SP CEP 09606-070 Brazil
- Graduate Program in Physical Education. State University of Londrina, Londrina, Paraná, Brazil
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50
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Khadka N, Truong DQ, Williams P, Martin JH, Bikson M. The Quasi-uniform assumption for Spinal Cord Stimulation translational research. J Neurosci Methods 2019; 328:108446. [PMID: 31589892 DOI: 10.1016/j.jneumeth.2019.108446] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 12/18/2022]
Abstract
BACKGROUND Quasi-uniform assumption is a general theory that postulates local electric field predicts neuronal activation. Computational current flow model of spinal cord stimulation (SCS) of humans and animal models inform how the quasi-uniform assumption can support scaling neuromodulation dose between humans and translational animal. NEW METHOD Here we developed finite element models of cat and rat SCS, and brain slice, alongside SCS models. Boundary conditions related to species specific electrode dimensions applied, and electric fields per unit current (mA) predicted. RESULTS Clinically and across animal, electric fields change abruptly over small distance compared to the neuronal morphology, such that each neuron is exposed to multiple electric fields. Per unit current, electric fields generally decrease with body mass, but not necessarily and proportionally across tissues. Peak electric field in dorsal column rat and cat were ∼17x and ∼1x of clinical values, for scaled electrodes and equal current. Within the spinal cord, the electric field for rat, cat, and human decreased to 50% of peak value caudo-rostrally (C5-C6) at 0.48 mm, 3.2 mm, and 8 mm, and mediolaterally at 0.14 mm, 2.3 mm, and 3.1 mm. Because these space constants are different, electric field across species cannot be matched without selecting a region of interest (ROI). COMPARISON WITH EXISTING METHOD This is the first computational model to support scaling neuromodulation dose between humans and translational animal. CONCLUSIONS Inter-species reproduction of the electric field profile across the entire surface of neuron populations is intractable. Approximating quasi-uniform electric field in a ROI is a rational step to translational scaling.
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Affiliation(s)
- Niranjan Khadka
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA.
| | - Dennis Q Truong
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Preston Williams
- Department of Molecular, Cellular, and Biomedical Sciences, City University of NY School of Medicine, New York, NY, 10031, USA
| | - John H Martin
- CUNY Graduate Center, New York, NY, 10031, USA; Department of Molecular, Cellular, and Biomedical Sciences, City University of NY School of Medicine, New York, NY, 10031, USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA.
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