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Sanchez-Romero R, Akyuz S, Krekelberg B. EFMouse: a Matlab toolbox to model electric fields in the mouse brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.25.605227. [PMID: 39091807 PMCID: PMC11291114 DOI: 10.1101/2024.07.25.605227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Compared to the rapidly growing literature on transcranial electrical stimulation (tES) in humans, research into the mechanisms underlying neuromodulation by tES using in-vivo animal models is growing but still relatively rare. Such research, however, is key to overcoming experimental limitations in humans and essential to build a detailed understanding of the in-vivo consequences of tES that can ultimately lead to development of targeted and effective therapeutic applications of noninvasive brain stimulation. The sheer difference in scale and geometry between animal models and the human brain contributes to the complexity of designing and interpreting animal studies. Here we extend previous approaches to model intracranial electric fields to generate predictions that can be tested with in-vivo intracranial recordings. Although the toolbox has general applicability and could be used to predict intracranial fields for any tES study using mice, we illustrate its usage by comparing fields in a high-density multi-electrode montage with a more traditional two electrode montage. Our simulations show that both montages can produce strong focal homogeneous electric fields in targeted areas. However, the high-density montage produces a field that is more perpendicular to the visual cortical surface, which is expected to result in larger changes in neuronal excitability. Highlights EFMouse is a novel, open-source, Matlab-based electric field simulator for the mouse brain.EFMouse quantifies field focality and homogeneity in regions of the Allen Mouse Brain Atlas.Focal and strong stimulation can be produced with two or five electrode montages.A high-density montage with a lumbar return generates fields perpendicular to the cortical surface.
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Zhang Y, Lu M. Numerical Simulation of Thermal Therapy for Melanoma in Mice. Bioengineering (Basel) 2024; 11:694. [PMID: 39061776 PMCID: PMC11273475 DOI: 10.3390/bioengineering11070694] [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: 06/09/2024] [Revised: 07/01/2024] [Accepted: 07/03/2024] [Indexed: 07/28/2024] Open
Abstract
In recent years, the progressively escalating incidence and exceptionally high fatality rate of cutaneous melanoma have drawn the attention of numerous scholars. Magnetic induction hyperthermia, as an efficacious tumor treatment modality, has been promoted and applied in the therapy of some tumors. In this paper, the melanoma atop the mice's heads was chosen as the research subject, and a magnetic induction hyperthermia approach based on Helmholtz coils as the magnetic field excitation was investigated and designed. The influence of the electromagnetic field and thermal field on organisms was addressed through modeling by COMSOL simulation software. The results showed that the maximum values of induced electric field and magnetic induction strength in mouse tumor tissues were 63.1 V/m and 8.5621 mT, respectively, which reached the threshold value of magnetic field strength required for magnetic induction hyperthermia. The maxima of the induced electric field and magnetic induction intensity in brain tissues are, respectively, 35.828 V/m and 8.57 mT. Approximately 93% of the tumor tissue can reach 42 °C, and the maximum temperature is 44.2 °C. Within this temperature range, a large quantity of tumor cells can be successfully induced to undergo apoptosis without harming normal cells, and the therapeutic effect is favorable.
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Affiliation(s)
| | - Mai Lu
- Key Laboratory of Opto-Electronic Technology and Intelligent Control of Ministry of Education, Lanzhou Jiaotong University, Lanzhou 730070, China;
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Gomez-Tames J, Asai A, Hirata A. Multiscale Computational Model Reveals Nerve Response in a Mouse Model for Temporal Interference Brain Stimulation. Front Neurosci 2021; 15:684465. [PMID: 34276293 PMCID: PMC8277927 DOI: 10.3389/fnins.2021.684465] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/08/2021] [Indexed: 12/24/2022] Open
Abstract
There has been a growing interest in the non-invasive stimulation of specific brain tissues, while reducing unintended stimulation in surrounding regions, for the medical treatment of brain disorders. Traditional methods for non-invasive brain stimulation, such as transcranial direct current stimulation (tDCS) or transcranial magnetic stimulation (TMS), can stimulate brain regions, but they also simultaneously stimulate the brain and non-brain regions that lie between the target and the stimulation site of the source. Temporal interference (TI) stimulation has been suggested to selectively stimulate brain regions by superposing two alternating currents with slightly different frequencies injected through electrodes attached to the scalp. Previous studies have reported promising results for TI applied to the motor area in mice, but the mechanisms are yet to be clarified. As computational techniques can help reveal different aspects of TI, in this study, we computationally investigated TI stimulation using a multiscale model that computes the generated interference current pattern effects in a neural cortical model of a mouse head. The results indicated that the threshold increased with the carrier frequency and that the beat frequency did not influence the threshold. It was also found that the intensity ratio between the alternating currents changed the location of the responding nerve, which is in agreement with previous experiments. Moreover, particular characteristics of the envelope were investigated to predict the stimulation region intuitively. It was found that regions with high modulation depth (| maximum| − | minimum| values of the envelope) and low minimum envelope (near zero) corresponded with the activation region obtained via neural computation.
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Affiliation(s)
- Jose Gomez-Tames
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, Japan.,Center of Biomedical Physics and Information Technology, Nagoya Institute of Technology, Nagoya, Japan
| | - Akihiro Asai
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, Japan
| | - Akimasa Hirata
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, Japan.,Center of Biomedical Physics and Information Technology, Nagoya Institute of Technology, Nagoya, Japan
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Turner DA, Degan S, Galeffi F, Schmidt S, Peterchev AV. Rapid, Dose-Dependent Enhancement of Cerebral Blood Flow by transcranial AC Stimulation in Mouse. Brain Stimul 2021; 14:80-87. [PMID: 33217607 PMCID: PMC7855527 DOI: 10.1016/j.brs.2020.11.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 10/18/2020] [Accepted: 11/12/2020] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Transcranial electrical stimulation at an appropriate dose may demonstrate intracranial effects, including neuronal stimulation and cerebral blood flow responses. OBJECTIVE We performed in vivo experiments on mouse cortex using transcranial alternating current [AC] stimulation to assess whether cerebral blood flow can be reliably altered by extracranial stimulation. METHODS We performed transcranial AC electrical stimulation transversely across the closed skull in anesthetized mice, measuring transcranial cerebral blood flow with a laser Doppler probe and intracranial electrical responses as endpoint biomarkers. We calculated a stimulation dose-response function between intracranial electric field and cerebral blood flow. RESULTS Stimulation at electric field amplitudes of 5-20 mV/mm at 10-20 Hz rapidly increased cerebral blood flow (within 100 ms), which then quickly decreased with no residual effects. The time to peak and blood flow shape varied with stimulation intensity and duration, showing a linear correlation between stimulation dose and peak blood flow increase. Neither afterdischarges nor spreading depression occurred from this level of stimulation. CONCLUSIONS Extracranial stimulation amplitudes sufficient to evoke reliable blood flow changes require electric field strengths higher than what is tolerable in unanesthetized humans (<1 mV/mm), but less than electroconvulsive therapy levels (>40 mV/mm). However, anesthesia effects, spontaneous blood flow fluctuations, and sampling error may accentuate the apparent field strength needed for enhanced blood flow. The translation to a human dose-response function to augment cerebral blood flow (i.e., in stroke recovery) will require significant modification, potentially to pericranial, focused, multi-electrode application or intracranial stimulation.
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Affiliation(s)
- Dennis A Turner
- Neurosurgery, Duke University, USA; Neurobiology, Duke University, USA; Biomedical Engineering, Duke University, USA; Surgery and Research Branches, Durham VAMC, Durham, NC, 27710, USA.
| | - Simone Degan
- Neurosurgery, Duke University, USA; Surgery and Research Branches, Durham VAMC, Durham, NC, 27710, USA
| | - Francesca Galeffi
- Neurosurgery, Duke University, USA; Surgery and Research Branches, Durham VAMC, Durham, NC, 27710, USA
| | - Stephen Schmidt
- Neurosurgery, Duke University, USA; Biomedical Engineering, Duke University, USA
| | - Angel V Peterchev
- Neurosurgery, Duke University, USA; Psychiatry & Behavioral Sciences, Duke University, USA; Biomedical Engineering, Duke University, USA; Electrical & Computer Engineering, Duke University, USA
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Alekseichuk I, Mantell K, Shirinpour S, Opitz A. Comparative modeling of transcranial magnetic and electric stimulation in mouse, monkey, and human. Neuroimage 2019; 194:136-148. [PMID: 30910725 PMCID: PMC6536349 DOI: 10.1016/j.neuroimage.2019.03.044] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/08/2019] [Accepted: 03/19/2019] [Indexed: 10/27/2022] Open
Abstract
Transcranial magnetic stimulation (TMS) and transcranial electric stimulation (TES) are increasingly popular methods to noninvasively affect brain activity. However, their mechanism of action and dose-response characteristics remain under active investigation. Translational studies in animals play a pivotal role in these efforts due to a larger neuroscientific toolset enabled by invasive recordings. In order to translate knowledge gained in animal studies to humans, it is crucial to generate comparable stimulation conditions with respect to the induced electric field in the brain. Here, we conduct a finite element method (FEM) modeling study of TMS and TES electric fields in a mouse, capuchin and macaque monkeys, and a human model. We systematically evaluate the induced electric fields and analyze their relationship to head and brain anatomy. We find that with increasing head size, TMS-induced electric field strength first increases and then decreases according to a two-term exponential function. TES-induced electric field strength strongly decreases from smaller to larger specimen with up to 100x fold differences across species. Our results can serve as a basis to compare and match stimulation parameters across studies in animals and humans.
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Affiliation(s)
- Ivan Alekseichuk
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA.
| | - Kathleen Mantell
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Sina Shirinpour
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Alexander Opitz
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA.
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Boonzaier J, van Tilborg GAF, Neggers SFW, Dijkhuizen RM. Noninvasive Brain Stimulation to Enhance Functional Recovery After Stroke: Studies in Animal Models. Neurorehabil Neural Repair 2018; 32:927-940. [PMID: 30352528 PMCID: PMC6238175 DOI: 10.1177/1545968318804425] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background. Stroke is the leading cause of adult disability, but treatment options remain limited, leaving most patients with incomplete recovery. Patient and animal studies have shown potential of noninvasive brain stimulation (NIBS) strategies to improve function after stroke. However, mechanisms underlying therapeutic effects of NIBS are unclear and there is no consensus on which NIBS protocols are most effective. Objective. Provide a review of articles that assessed effects and mechanisms of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) in animal stroke models. Methods. Articles were searched in PubMed, including cross-references. Results. Nineteen eligible studies reporting effects of rTMS or tDCS after stroke in small rodents were identified. Seventeen of those described improved functional recovery or neuroprotection compared with untreated control or sham-stimulated groups. The effects of rTMS could be related to molecular mechanisms associated with ischemic tolerance, neuroprotection, anti-apoptosis, neurogenesis, angiogenesis, or neuroplasticity. Favorable outcome appeared most effectively when using high-frequency (>5 Hz) rTMS or intermittent theta burst stimulation of the ipsilesional hemisphere. tDCS effects were strongly dependent on stimulation polarity and onset time. Although these findings are promising, most studies did not meet Good Laboratory Practice assessment criteria. Conclusions. Despite limited data availability, animal stroke model studies demonstrate potential of NIBS to promote stroke recovery through different working mechanisms. Future studies in animal stroke models should adhere to Good Laboratory Practice guidelines and aim to further develop clinically applicable treatment protocols by identifying most favorable stimulation parameters, treatment onset, adjuvant therapies, and underlying modes of action.
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Affiliation(s)
- Julia Boonzaier
- 1 Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Geralda A F van Tilborg
- 1 Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Sebastiaan F W Neggers
- 2 Brain Center Rudolf Magnus, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
| | - Rick M Dijkhuizen
- 1 Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, Netherlands
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Abstract
Modulating deep regions of the brain with noninvasive technology has challenged researchers for decades. In a new study, Grossman et al. leverage the emergence of a slowly oscillating "beat" from intersecting high-frequency electric fields to stimulate deep brain regions, opening a frontier in the biophysics and technology of brain stimulation.
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Affiliation(s)
- Jacek Dmochowski
- Department of Biomedical Engineering, The City College of New York of CUNY, New York, NY 10031, USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York of CUNY, New York, NY 10031, USA.
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Jackson MP, Rahman A, Lafon B, Kronberg G, Ling D, Parra LC, Bikson M. Animal models of transcranial direct current stimulation: Methods and mechanisms. Clin Neurophysiol 2016; 127:3425-3454. [PMID: 27693941 PMCID: PMC5083183 DOI: 10.1016/j.clinph.2016.08.016] [Citation(s) in RCA: 191] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 08/05/2016] [Accepted: 08/08/2016] [Indexed: 12/28/2022]
Abstract
The objective of this review is to summarize the contribution of animal research using direct current stimulation (DCS) to our understanding of the physiological effects of transcranial direct current stimulation (tDCS). We comprehensively address experimental methodology in animal studies, broadly classified as: (1) transcranial stimulation; (2) direct cortical stimulation in vivo and (3) in vitro models. In each case advantages and disadvantages for translational research are discussed including dose translation and the overarching "quasi-uniform" assumption, which underpins translational relevance in all animal models of tDCS. Terminology such as anode, cathode, inward current, outward current, current density, electric field, and uniform are defined. Though we put key animal experiments spanning decades in perspective, our goal is not simply an exhaustive cataloging of relevant animal studies, but rather to put them in context of ongoing efforts to improve tDCS. Cellular targets, including excitatory neuronal somas, dendrites, axons, interneurons, glial cells, and endothelial cells are considered. We emphasize neurons are always depolarized and hyperpolarized such that effects of DCS on neuronal excitability can only be evaluated within subcellular regions of the neuron. Findings from animal studies on the effects of DCS on plasticity (LTP/LTD) and network oscillations are reviewed extensively. Any endogenous phenomena dependent on membrane potential changes are, in theory, susceptible to modulation by DCS. The relevance of morphological changes (galvanotropy) to tDCS is also considered, as we suggest microscopic migration of axon terminals or dendritic spines may be relevant during tDCS. A majority of clinical studies using tDCS employ a simplistic dose strategy where excitability is singularly increased or decreased under the anode and cathode, respectively. We discuss how this strategy, itself based on classic animal studies, cannot account for the complexity of normal and pathological brain function, and how recent studies have already indicated more sophisticated approaches are necessary. One tDCS theory regarding "functional targeting" suggests the specificity of tDCS effects are possible by modulating ongoing function (plasticity). Use of animal models of disease are summarized including pain, movement disorders, stroke, and epilepsy.
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Affiliation(s)
- Mark P Jackson
- Department of Biomedical Engineering, The City College of The City University of New York, NY, USA
| | - Asif Rahman
- Department of Biomedical Engineering, The City College of The City University of New York, NY, USA
| | - Belen Lafon
- Department of Biomedical Engineering, The City College of The City University of New York, NY, USA
| | - Gregory Kronberg
- Department of Biomedical Engineering, The City College of The City University of New York, NY, USA
| | - Doris Ling
- Department of Biomedical Engineering, The City College of The City University of New York, NY, USA
| | - Lucas C Parra
- Department of Biomedical Engineering, The City College of The City University of New York, NY, USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of The City University of New York, NY, USA.
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Barnes WL, Lee WH, Peterchev AV. Approximating transcranial magnetic stimulation with electric stimulation in mouse: a simulation study. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2014:6129-32. [PMID: 25571396 DOI: 10.1109/embc.2014.6945028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rodent models are valuable for preclinical examination of novel therapeutic techniques, including transcranial magnetic stimulation (TMS). However, comparison of TMS effects in rodents and humans is confounded by inaccurate scaling of the spatial extent of the induced electric field in rodents. The electric field is substantially less focal in rodent models of TMS due to the technical restrictions of making very small coils that can handle the currents required for TMS. We examine the electric field distributions generated by various electrode configurations of electric stimulation in an inhomogeneous high-resolution finite element mouse model, and show that the electric field distributions produced by human TMS can be approximated by electric stimulation in mouse. Based on these results and the limits of magnetic stimulation in mice, we argue that the most practical and accurate way to model focal TMS in mice is electric stimulation through either cortical surface electrodes or electrodes implanted halfway through the mouse cranium. This approach could allow much more accurate approximation of the human TMS electric field focality and strength than that offered by TMS in mouse, enabling, for example, focal targeting of specific cortical regions, which is common in human TMS paradigms.
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