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Schlosser-Perrin F, Rossel O, Duffau H, Bonnetblanc F, Mandonnet E. How far does electrical stimulation activate white matter tracts? A computational modeling study. Clin Neurophysiol 2023; 153:68-78. [PMID: 37459667 DOI: 10.1016/j.clinph.2023.06.017] [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: 02/11/2023] [Revised: 06/08/2023] [Accepted: 06/16/2023] [Indexed: 08/21/2023]
Abstract
OBJECTIVE The aim of this study was to model how the different parameters of electrical stimulation (intensity, pulse shape, probe geometry) influence the extent of white matter activation. METHODS The electrical potentials generated by the stimulating electrodes were determined by solving Laplace equation. The temporal evolution of membrane potentials at each nodes of Ranvier of an axon was then computed by solving the coupled system of differential equations describing membrane dynamics and cable propagation. RESULTS Regions of unilateral propagation were observed for monophasic pulses delivered with a bipolar probe aligned along the tract. For biphasic pulses, the largest activation areas and depths were found with a high inter-electrode-distance (IED) bipolar probe, oriented orthogonally to the tract. The smallest activation areas and depths were found for bipolar stimulations with the probe aligned parallel to the tract and low IED. For isotropic white matter regions, the activation area and depth were three times larger than for anisotropic white matter tracts. CONCLUSIONS Bipolar probes with biphasic pulses offer the greatest versatility: an orthogonal orientation acts as two monopolars (increased sensitivity when searching for a tract), whereas a parallel orientation corresponds to a single monopolar (increased specificity). Activation is more superficial when stimulating highly anisotropic tracts. SIGNIFICANCE This knowledge is essential for interpreting the behavorial effects of stimulation and the recordings of axono-cortical evoked potentials.
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Affiliation(s)
| | | | - Hugues Duffau
- Département de Neurochirurgie, Centre Hospitalier Universitaire de Montpellier Gui de Chauliac, Montpellier, France; Team "Neuroplasticity, Stem Cells and Glial Tumors", Institute of Functional Genomics, INSERM U-1191, University of Montpellier, 34090 Montpellier, France; Université de Montpellier, Montpellier, France
| | | | - Emmanuel Mandonnet
- Frontlab, Paris Brain Institute, CNRS UMR 7225, INSERM U1127, Paris, France; Department of Neurosurgery, Lariboisière Hospital, Paris, France; Université de Paris Cité, Paris, France.
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Le Lann F, Cristante J, De Schlichting E, Quehan R, Réhault E, Lotterie JA, Roux FE. Variability of Intraoperative Electrostimulation Parameters in Conscious Individuals: Language Fasciculi. World Neurosurg 2022; 164:e194-e202. [PMID: 35472645 DOI: 10.1016/j.wneu.2022.04.066] [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: 02/17/2022] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
Abstract
OBJECTIVE The authors analyzed the current-intensity thresholds for electrostimulation of language fasciculi and the possible consequences of threshold variability on brain mapping. METHODS A prospective protocol of subcortical electrostimulation was used in 50 patients undergoing brain mapping, directly stimulating presumed language fasciculi identified by diffusion tensor imaging. RESULTS The stimulation-intensity thresholds for identification of language fasciculi varied among patients (mean minimum current intensity of 4.4 mA, range = 1.5-10 mA, standard deviation = 1.1 mA), and 23% of fascicular interferences were detected only above 5 mA. Repeated stimulation of the same site with the same intensity led to different types of interferences in 20% of patients, and a higher current intensity led to changes in the type of response in 27%. The mean minimum stimulation intensities did not differ significantly between different fasciculi, between the different types of interference obtained, or with age, sex, or type of tumor. Positive results on cortical mapping were significantly associated with positive results on subcortical mapping (P < 0.001). Subcortical intensity thresholds were slightly lower than cortical ones (mean = 4.43 vs. 5.25 mA, P = 0.034). In 23 of 50 subcortical mappings, fascicular stimulation produced no language interference. CONCLUSIONS Individual variability of minimum stimulation-intensity thresholds for identification of language fasciculi is frequent. Nevertheless, even when a high current intensity was used, many stimulations on language fasciculi remained negative for various hypothetic reasons. Finding the optimal current intensity for identifying language fasciculi is of paramount importance to refine the clinical results and scientific data derived from brain mapping.
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Affiliation(s)
- Florian Le Lann
- Pole Neurosciences (Neurochirurgie), Centre Hospitalo-Universitaire de Toulouse, Toulouse, France; Université de Toulouse, UPS, Toulouse, France.
| | | | - Emmanuel De Schlichting
- Université Grenoble Alpes, Faculté de Médecine, Grenoble, France; Neurochirurgie, Centre Hospitalo-Universitaire de Grenoble, Toulouse, France
| | - Romain Quehan
- Pole Neurosciences (Neurochirurgie), Centre Hospitalo-Universitaire de Toulouse, Toulouse, France; Université de Toulouse, UPS, Toulouse, France
| | - Emilie Réhault
- Pole Neurosciences (Neurochirurgie), Centre Hospitalo-Universitaire de Toulouse, Toulouse, France
| | - Jean-Albert Lotterie
- Pole Neurosciences (Neurochirurgie), Centre Hospitalo-Universitaire de Toulouse, Toulouse, France; Université de Toulouse, UPS, Toulouse, France
| | - Franck-Emmanuel Roux
- Pole Neurosciences (Neurochirurgie), Centre Hospitalo-Universitaire de Toulouse, Toulouse, France; Université de Toulouse, UPS, Toulouse, France; Centre de Recherche Cerveau et Cognition (CNRS; CerCo), Toulouse, France
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Dragoy O, Zyryanov A, Bronov O, Gordeyeva E, Gronskaya N, Kryuchkova O, Klyuev E, Kopachev D, Medyanik I, Mishnyakova L, Pedyash N, Pronin I, Reutov A, Sitnikov A, Stupina E, Yashin K, Zhirnova V, Zuev A. Functional linguistic specificity of the left frontal aslant tract for spontaneous speech fluency: Evidence from intraoperative language mapping. BRAIN AND LANGUAGE 2020; 208:104836. [PMID: 32673898 DOI: 10.1016/j.bandl.2020.104836] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 05/22/2020] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
The left frontal aslant tract (FAT) has been proposed to be relevant for language, and specifically for spontaneous speech fluency. However, there is missing causal evidence that stimulation of the FAT affects spontaneous speech, and not language production in general. We present a series of 12 neurosurgical cases with awake language mapping of the cortex near the left FAT. Tasks for language mapping included the commonly used action picture naming, and sentence completion, tapping more specifically into spontaneous speech. A task dissociation was found in 10 participants: while being stimulated on specific sites, they were able to name a picture but could not complete a sentence. Overlaying of these sites on preoperative white-matter tract reconstructions revealed that in each individual case they were located on cortical terminations of the FAT. This corroborates the language functional specificity of the left FAT as a tract underlying fluent spontaneous speech.
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Affiliation(s)
- Olga Dragoy
- Center for Language and Brain, National Research University Higher School of Economics, Moscow, Russia.
| | - Andrey Zyryanov
- Center for Language and Brain, National Research University Higher School of Economics, Moscow, Russia
| | - Oleg Bronov
- Department of Radiology, National Medical and Surgical Center Named after N. I. Pirogov, Moscow, Russia
| | - Elizaveta Gordeyeva
- Center for Language and Brain, National Research University Higher School of Economics, Moscow, Russia
| | - Natalya Gronskaya
- Faculty of Humanities, National Research University Higher School of Economics, Nizhny Novgorod, Russia
| | - Oksana Kryuchkova
- Department of Radiology, Central Clinical Hospital with Outpatient Health Center of the Business Administration for the President of the Russian Federation, Moscow, Russia
| | - Evgenij Klyuev
- Department of Radiology, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Dmitry Kopachev
- Department of Neurosurgery, National Medical Research Center for Neurosurgery Named after N. N. Burdenko, Moscow, Russia
| | - Igor Medyanik
- Department of Neurosurgery, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Lidiya Mishnyakova
- Department of Neurosurgery, Federal Centre of Treatment and Rehabilitation of the Ministry of Healthcare of the Russian Federation, Moscow, Russia
| | - Nikita Pedyash
- Department of Neurosurgery, National Medical and Surgical Center Named after N. I. Pirogov, Moscow, Russia
| | - Igor Pronin
- Department of Neuroradiology, National Medical Research Center for Neurosurgery Named after N. N. Burdenko, Moscow, Russia
| | - Andrey Reutov
- Department of Neurosurgery, Central Clinical Hospital with Outpatient Health Center of the Business Administration for the President of the Russian Federation, Moscow, Russia
| | - Andrey Sitnikov
- Department of Neurosurgery, Federal Centre of Treatment and Rehabilitation of the Ministry of Healthcare of the Russian Federation, Moscow, Russia
| | - Ekaterina Stupina
- Center for Language and Brain, National Research University Higher School of Economics, Moscow, Russia
| | - Konstantin Yashin
- Department of Neurosurgery, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Valeriya Zhirnova
- Center for Language and Brain, National Research University Higher School of Economics, Moscow, Russia
| | - Andrey Zuev
- Department of Neurosurgery, National Medical and Surgical Center Named after N. I. Pirogov, Moscow, Russia
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Lindberg KR, Dougherty ET. Location Specificity of Transcranial Electrical Stimulation on Neuronal Electrodynamics: A Mathematical Model of Ion Channel Gating Dynamics and Ionic Flux Due to Neurostimulation. Front Comput Neurosci 2019; 13:17. [PMID: 31019457 PMCID: PMC6458477 DOI: 10.3389/fncom.2019.00017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 03/11/2019] [Indexed: 11/18/2022] Open
Abstract
Transcranial Electrical Stimulation (TES) continues to demonstrate success as a medical intervention for individuals with neurodegenerative diseases. Despite promising results from these neuromodulation modalities, the cellular level mechanisms by which this neurotherapy operates are not fully comprehended. In particular, the effects of TES on ion channel gating and ion transport are not known. Using the Poisson-Nernst-Planck model of electrodiffusion, coupled with a Hodgkin-Huxley based model of cellular ion transport, we present a model of TES that, for the first time, integrates electric potential energy, individualized ion species, voltage-gated ion channels, and transmembrane ionic flux during TES administration. Computational simulations are executed on a biologically-inspired domain with medically-based TES treatment parameters and quantify neuron-level electrical processes resulting from this form of neurostimulation. Results confirm prior findings that show that TES polarizes the cell membrane, however, these are extended as simulations in this paper show that polarization occurs in a location specific manner, where the type and degree of polarization depends on the position on the membrane within a node of Ranvier. In addition, results demonstrate that TES causes ion channel gating variables to change in a location specific fashion and, as a result, transmembrane current from distinct ion species depends on both time and membrane location. Another simulation finding is that intracellular calcium concentrations increase significantly due to a TES-induced calcium influx. As cytosolic calcium is critical in intracellular signaling pathways that govern proper neurotransmitter secretion as well as support cell viability, this alteration in calcium homeostasis suggests a possible mechanism by which TES operates at the neuronal level to achieve neurotherapeutic success.
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Affiliation(s)
- Kaia R Lindberg
- Mathematics Department, Roger Williams University, Bristol, RI, United States
| | - Edward T Dougherty
- Mathematics Department, Roger Williams University, Bristol, RI, United States
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Visualization of Brain Shift Corrected Functional Magnetic Resonance Imaging Data for Intraoperative Brain Mapping. World Neurosurg X 2019; 2:100021. [PMID: 31218295 PMCID: PMC6580887 DOI: 10.1016/j.wnsx.2019.100021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 02/06/2019] [Indexed: 11/22/2022] Open
Abstract
Background Brain tumor surgery requires careful balance between maximizing tumor excision and preserving eloquent cortex. In some cases, the surgeon may opt to perform an awake craniotomy including intraoperative mapping of brain function by direct cortical stimulation (DCS) to assist in surgical decision-making. Preoperatively, functional magnetic resonance imaging (fMRI) facilitates planning by identification of eloquent brain areas, helping to guide DCS and other aspects of the surgical plan. However, brain deformation (shift) limits the usefulness of preoperative fMRI during surgery. To address this, an integrated visualization method for fMRI and DCS results is developed that is intuitive for the surgeon. Methods An image registration pipeline was constructed to display preoperative fMRI data corrected for brain shift overlaid on images of the exposed cortical surface at the beginning and completion of DCS mapping. Preoperative fMRI and DCS data were registered for a range of misalignments, and the residual registration errors were calculated. The pipeline was validated on imaging data from five brain tumor patients who underwent awake craniotomy. Results Registration errors were well under 5 mm (the approximate spatial resolution of DCS) for misalignments of up to 25 mm and approximately 10–15°. For rotational misalignments up to 20°, the success rate was 95% for an error tolerance of 5 mm. Failures were negligible for rotational misalignments up to 10°. Good quality registrations were observed for all five patients. Conclusions A proof-of-concept image registration pipeline is presented with acceptable accuracy for intraoperative use, providing multimodality visualization with potential benefits for intraoperative brain mapping.
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Key Words
- 2D, 2-dimensional
- 3D, 3-Dimensional
- Awake craniotomy
- Brain mapping
- Brain tumor resection
- CT, Computed tomography
- DCS, Direct cortical stimulation
- Electric stimulation
- FOV, Field of view
- Functional mapping
- MRI, Magnetic resonance imaging
- Multimodal imaging
- RE, Registration error
- Surgical planning
- TE, Echo time
- TR, Repetition time
- fMRI, Functional magnetic resonance imaging
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Gomez-Tames J, Kutsuna T, Tamura M, Muragaki Y, Hirata A. Intraoperative direct subcortical stimulation: comparison of monopolar and bipolar stimulation. Phys Med Biol 2018; 63:225013. [PMID: 30418938 DOI: 10.1088/1361-6560/aaea06] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Intraoperative subcortical electrical stimulation is used to identify and preserve white matter tracts so that tumor resection can be performed while avoiding postsurgical deficits. The effects of the stimulating electrodes in identifying the white matter tracts have not been characterized; thus, different hospitals use different electrode configurations. Computational modeling can be used to conduct a systematic assessment of the effects of the stimulating electrode parameters. However, no realistic computational model of subcortical electrical stimulation has been implemented and verified. In this study, we investigated the interaction between the corticospinal tract (CST) and subcortical stimulation and compared different electrode configurations during monopolar and bipolar stimulation. For that, we computed the induced electric field in a realistic human head model coupled with a CST axon model. The implemented model was verified with available experimental data that were acquired during subcortical stimulation, and a systematic sensitivity analysis of parameters related to the stimulation was conducted. The results showed that the optimal stimulation varies according to the surgery conditions. If the CST was close to the resection border, bipolar stimulation could produce more selective activation. Monopolar stimulation was more robust and more effective for the CST far from the stimulation point.
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Affiliation(s)
- Jose Gomez-Tames
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, Aichi 466-8555, Japan. Author to whom any correspondence should be addressed
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Pallud J, Mandonnet E, Corns R, Dezamis E, Parraga E, Zanello M, Spena G. Technical principles of direct bipolar electrostimulation for cortical and subcortical mapping in awake craniotomy. Neurochirurgie 2017; 63:158-163. [DOI: 10.1016/j.neuchi.2016.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 11/24/2016] [Accepted: 12/04/2016] [Indexed: 12/01/2022]
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Multiscale coupling of transcranial direct current stimulation to neuron electrodynamics: modeling the influence of the transcranial electric field on neuronal depolarization. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2014; 2014:360179. [PMID: 25404950 PMCID: PMC4227389 DOI: 10.1155/2014/360179] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 09/17/2014] [Indexed: 11/18/2022]
Abstract
Transcranial direct current stimulation (tDCS) continues to demonstrate success as a medical intervention for neurodegenerative diseases, psychological conditions, and traumatic brain injury recovery. One aspect of tDCS still not fully comprehended is the influence of the tDCS electric field on neural functionality. To address this issue, we present a mathematical, multiscale model that couples tDCS administration to neuron electrodynamics. We demonstrate the model's validity and medical applicability with computational simulations using an idealized two-dimensional domain and then an MRI-derived, three-dimensional human head geometry possessing inhomogeneous and anisotropic tissue conductivities. We exemplify the capabilities of these simulations with real-world tDCS electrode configurations and treatment parameters and compare the model's predictions to those attained from medical research studies. The model is implemented using efficient numerical strategies and solution techniques to allow the use of fine computational grids needed by the medical community.
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