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Bok I, Phillips J, Zhu T, Lu J, Detienne E, Lima EA, Weiss BP, Jasanoff A, Hai A. Magnetic Detection of Neural Activity by Nanocoil Transducers. NANO LETTERS 2024. [PMID: 39319575 DOI: 10.1021/acs.nanolett.4c02784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2024]
Abstract
Electrophysiological recordings from brain cells are performed routinely using implanted electrodes, but they traditionally require a wired connection to the outside of the brain. A completely passive, wireless device that does not require on-board power for active transmission but that still facilitates remote detection could open the door for mass-scale direct recording of action potentials and transform the way we acquire brain signals. We present a nanofabricated coil that forms a neuroelectromagnetic junction, yielding a highly enhanced magnetic field transduction of electrophysiology. We show that this micrometer-scale device enables remote magnetic detection of neuronal fields from the center of the coil using room temperature superconducting quantum interference device (SQUID) microscopy. Further, time-locked stimulation in conjunction with magnetometry demonstrates thresholding behavior that affirms the viability of the technology for detection with no requirement for wires or on-board power. This strategy may permit unprecedented detection of electrophysiology using magnetoencephalography and magnetic resonance imaging.
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Affiliation(s)
- Ilhan Bok
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Jack Phillips
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Tianxiang Zhu
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Jennifer Lu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02108, United States
| | - Elizabeth Detienne
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02108, United States
| | - Eduardo Andrade Lima
- Department of Earth and Planetary Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Benjamin P Weiss
- Department of Earth and Planetary Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alan Jasanoff
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02108, United States
- Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Nuclear Science & Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Aviad Hai
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02108, United States
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Kim HG, Yoon Y, Lee MB, Jeong J, Lee J, Kwon OI, Jahng GH. Functional MRI study with conductivity signal changes during visual stimulation. J Neurosci Methods 2024; 412:110288. [PMID: 39306011 DOI: 10.1016/j.jneumeth.2024.110288] [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: 06/03/2024] [Revised: 08/27/2024] [Accepted: 09/12/2024] [Indexed: 09/28/2024]
Abstract
BACKGROUND Although blood oxygen level-dependent (BOLD) functional MRI (fMRI) is a standard method, major BOLD signals primarily originate from intravascular sources. Magnetic resonance electrical properties tomography (MREPT)-based fMRI signals may provide additional insights into electrical activity caused by alterations in ion concentrations and mobilities. PURPOSE This study aimed to investigate the neuronal response of conductivity during visual stimulation and compare it with BOLD. MATERIALS AND METHODS A total of 30 young, healthy volunteers participated in two independent experiments using BOLD and MREPT techniques with a visual stimulation paradigm at 3 T MRI. The first set of MREPT fMRI data was obtained using a multi-echo spin-echo (SE) echo planar imaging (EPI) sequence from 14 participants. The second set of MREPT fMRI data was collected from 16 participants using both a single-echo SE-EPI and a single-echo three-dimensional (3D) balanced fast-field-echo (bFFE) sequence. We reconstructed the time-course Larmor frequency conductivity to evaluate hemodynamics. RESULTS Conductivity values slightly increased during visual stimulation. Activation strengths were consistently stronger with BOLD than with conductivity for both SE-EPI MREPT and bFFE MREPT. Additionally, the activated areas were always larger with BOLD than MREPT. Some participants also exhibited decreased conductivity values during visual stimulations. In Experiment 1, conductivity showed significant differences between the fixation and visual stimulation blocks in the secondary visual cortex (SVC) and cuneus, with conductivity differences of 0.43 % and 0.47 %, respectively. No significant differences in conductivity were found in the cerebrospinal fluid (CSF) areas between the two blocks. In Experiment 2, significant conductivity differences were observed between the two blocks in the SVC, cuneus, and lingual gyrus for SE-EPI MREPT, with differences of 0.90 %, 0.67 %, and 0.24 %, respectively. Again, no significant differences were found in the CSF areas. CONCLUSION Conductivity values increased slightly during visual stimulation in the visual cortex areas but were much weaker than BOLD responses. The conductivity change during visual stimulation was less than 1 % compared to the fixation block. No significant differences in conductivity were observed between the primary visual cortex (PVC)-CSF and SVC-CSF during fixation and visual stimulations, suggesting that the observed conductivity changes may not be related to CSF changes in the visual cortex but rather to diffusion changes. Future research should explore the potential of MREPT to detect neuronal electrical activity and hemodynamic changes, with further optimization of the MREPT technique.
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Affiliation(s)
- Hyug-Gi Kim
- Department of Radiology, Kyung Hee University Hospital, Dongdaemoon-gu, Seoul, South Korea
| | - Youngeun Yoon
- Department of Biomedical Engineering, Undergraduate School, College of Electronics and Information, Kyung Hee University, Giheung-gu, Yongin-si, Gyeonggi-do, South Korea
| | - Mun Bae Lee
- Department of Mathematics, College of Basic Science, Konkuk University, Seoul, Gwangjin-gu, South Korea
| | - Jeongin Jeong
- Department of Biomedical Engineering, Undergraduate School, College of Electronics and Information, Kyung Hee University, Giheung-gu, Yongin-si, Gyeonggi-do, South Korea
| | - Jiyoon Lee
- Department of Biomedical Engineering, Undergraduate School, College of Electronics and Information, Kyung Hee University, Giheung-gu, Yongin-si, Gyeonggi-do, South Korea
| | - Oh In Kwon
- Department of Mathematics, College of Basic Science, Konkuk University, Seoul, Gwangjin-gu, South Korea
| | - Geon-Ho Jahng
- Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul, Gangdong-Gu, South Korea.
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Emerging trends and hot spots on electrical impedance tomography extrapulmonary applications. Heliyon 2022; 8:e12458. [PMID: 36619470 PMCID: PMC9812712 DOI: 10.1016/j.heliyon.2022.e12458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 10/17/2022] [Accepted: 12/13/2022] [Indexed: 01/04/2023] Open
Abstract
Objective Electrical impedance tomography (EIT) develops rapidly in technology and applications. Nowadays EIT is used in multiple clinical and experimental scenarios including pulmonary, brain, and tissue monitoring, etc. The present study explores the research trends and hotspots on EIT extrapulmonary application research by bibliometrics analysis. Approach Publications on EIT extrapulmonary applications between 1987 and 2021 were retrieved from the Web of Science Core Collection database. For precise screening, search strategy "electrical impedance tomography" plus "hemodynamic" or "brain" or "nerve" or "cancer" or "venous" or "vessel" or "tumor" or "veterinary" or "tissue" or "cell" or "wearable" or "application" and excluding "lung", "ventilation" "respiratory", "pulmonary", "algorithm", "current", "voltage" or "electrode" were used. CiteSpace and VOSviewer were used to analyze the publication features, collaboration, keywords co-occurrence, and co-cited reference. Main results A total of 506 articles were finally identified. The global publication numbers on extrapulmonary applications gradually increased yearly in the past 30 years. The US, UK, and China contributed most three publications concerning EIT extrapulmonary applications. "tissues", "conductivity", "model" were research hotspots, and "cutaneous melanoma", "microstructure", "diagnosis" were recent topics (Portions of this research have previously been presented in poster form). Significance Overall, EIT extrapulmonary applications bibliometrics analysis provides a unique insight into research focus, current trends, and future directions.
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Schwartz BL, Brown SM, Muthuswamy J, Sadleir RJ. Analytic modeling of neural tissue: II. Nonlinear membrane dynamics. AIP ADVANCES 2022; 12:115019. [PMID: 36397822 PMCID: PMC9665963 DOI: 10.1063/5.0124414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
Computational modeling of neuroactivity plays a central role in our effort to understand brain dynamics in the advancements of neural engineering such as deep brain stimulation, neuroprosthetics, and magnetic resonance electrical impedance tomography. However, analytic solutions do not capture the fundamental nonlinear behavior of an action potential. What is needed is a method that is not constrained to only linearized models of neural tissue. Therefore, the objective of this study is to establish a robust, straightforward process for modeling neurodynamic phenomena, which preserves their nonlinear features. To address this, we turn to decomposition methods from homotopy analysis, which have emerged in recent decades as powerful tools for solving nonlinear differential equations. We solve the nonlinear ordinary differential equations of three landmark models of neural conduction-Ermentrout-Kopell, FitzHugh-Nagumo, and Hindmarsh-Rose models-using George Adomian's decomposition method. For each variable, we construct a power series solution equivalent to a generalized Taylor series expanded about a function. The first term of the decomposition series comes from the models' initial conditions. All subsequent terms are recursively determined from the first. We show rapid convergence, achieving a maximal error of < 1 0 - 12 with only eight terms. We extend the region of convergence with one-step analytic continuation so that our complete solutions are decomposition splines. We show that this process can yield solutions for single- and multi-variable models and can characterize a single action potential or complex bursting patterns. Finally, we show that the accuracy of this decomposition approach favorably compares to an established polynomial method, B-spline collocation. The strength of this method, besides its stability and ease of computation, is that, unlike perturbation, we make no changes to the models' equations; thus, our solutions are to the problems at hand, not simplified versions. This work validates decomposition as a viable technique for advanced neural engineering studies.
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Affiliation(s)
| | - S. M. Brown
- School of Computing, Informatics, and Decision Systems Engineering, Arizona State University, 699 S Mill Avenue, Tempe, Arizona 85281-3636, USA
| | - J. Muthuswamy
- School of Biological and Health Systems Engineering, Arizona State University, 501 E Tyler Mall, Tempe, Arizona 85287-9709, USA
| | - R. J. Sadleir
- School of Biological and Health Systems Engineering, Arizona State University, 501 E Tyler Mall, Tempe, Arizona 85287-9709, USA
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Phillips J, Glodowski M, Gokhale Y, Dwyer M, Ashtiani A, Hai A. Enhanced magnetic transduction of neuronal activity by nanofabricated inductors quantified via finite element analysis. J Neural Eng 2022; 19:10.1088/1741-2552/ac7907. [PMID: 35705065 PMCID: PMC9400688 DOI: 10.1088/1741-2552/ac7907] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 06/15/2022] [Indexed: 11/11/2022]
Abstract
Objective.Methods for the detection of neural signals involve a compromise between invasiveness, spatiotemporal resolution, and the number of neurons or brain regions recorded. Electrode-based probes provide excellent response but usually require transcranial wiring and capture activity from limited neuronal populations. Noninvasive methods such as electroencephalography and magnetoencephalography offer fast readouts of field potentials or biomagnetic signals, respectively, but have spatial constraints that prohibit recording from single neurons. A cell-sized device that enhances neurogenic magnetic fields can be used as anin situsensor for magnetic-based modalities and increase the ability to detect diverse signals across multiple brain regions.Approach.We designed and modeled a device capable of forming a tight electromagnetic junction with single neurons, thereby transducing changes in cellular potential to magnetic field perturbations by driving current through a nanofabricated inductor element.Main results.We present detailed quantification of the device performance using realistic finite element simulations with signals and geometries acquired from patch-clamped neuronsin vitroand demonstrate the capability of the device to produce magnetic signals readable via existing modalities. We compare the magnetic output of the device to intrinsic neuronal magnetic fields (NMFs) and show that the transduced magnetic field intensity from a single neuron is more than three-fold higher at its peak (1.62 nT vs 0.51 nT). Importantly, we report on a large spatial enhancement of the transduced magnetic field output within a typical voxel (40 × 40 × 10µm) over 250 times higher than the intrinsic NMF strength (0.64 nT vs 2.5 pT). We use this framework to perform optimizations of device performance based on nanofabrication constraints and material choices.Significance.Our quantifications institute a foundation for synthesizing and applying electromagnetic sensors for detecting brain activity and can serve as a general method for quantifying recording devices at the single cell level.
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Affiliation(s)
- Jack Phillips
- Department of Biomedical Engineering, University of Wisconsin–Madison
- Wisconsin Institute for Translational Neuroengineering (WITNe), University of Wisconsin-Madison
| | | | - Yash Gokhale
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Matt Dwyer
- Department of Biomedical Engineering, University of Wisconsin–Madison
- Department of Electrical and Computer Engineering, University of Wisconsin–Madison
| | - Alireza Ashtiani
- Department of Biomedical Engineering, University of Wisconsin–Madison
| | - Aviad Hai
- Department of Biomedical Engineering, University of Wisconsin–Madison
- Department of Electrical and Computer Engineering, University of Wisconsin–Madison
- Wisconsin Institute for Translational Neuroengineering (WITNe), University of Wisconsin-Madison
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Sadleir R, Gabriel C, Minhas AS. Electromagnetic Properties and the Basis for CDI, MREIT, and EPT. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1380:1-16. [DOI: 10.1007/978-3-031-03873-0_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Ashok Kumar N, Chauhan M, Kandala SK, Sohn SM, Sadleir RJ. Development and testing of implanted carbon electrodes for electromagnetic field mapping during neuromodulation. Magn Reson Med 2020; 84:2103-2116. [PMID: 32301176 DOI: 10.1002/mrm.28273] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/01/2020] [Accepted: 03/11/2020] [Indexed: 02/05/2023]
Abstract
PURPOSE Deep brain stimulation electrodes composed of carbon fibers were tested as a means of administering and imaging magnetic resonance electrical impedance tomography (MREIT) currents. Artifacts and heating properties of custom carbon-fiber deep brain stimulation (DBS) electrodes were compared with those produced with standard DBS electrodes. METHODS Electrodes were constructed from multiple strands of 7-μm carbon-fiber stock. The insulated carbon electrodes were matched to DBS electrode diameter and contact areas. Images of DBS and carbon electrodes were collected with and without current flow and were compared in terms of artifact and thermal effects in phantoms or tissue samples in 7T imaging conditions. Effects on magnetic flux density and current density distributions were also assessed. RESULTS Carbon electrodes produced magnitude artifacts with smaller FWHM values compared to the magnitude artifacts around DBS electrodes in spin echo and gradient echo imaging protocols. DBS electrodes appeared 269% larger than actual size in gradient echo images, in sharp contrast to the negligible artifact observed in diameter-matched carbon electrodes. As expected, larger temperature changes were observed near DBS electrodes during extended RF excitations compared with carbon electrodes in the same phantom. Magnitudes and distribution of magnetic flux density and current density reconstructions were comparable for carbon and DBS electrodes. CONCLUSION Carbon electrodes may offer a safer, MR-compatible method for administering neuromodulation currents. Use of carbon-fiber electrodes should allow imaging of structures close to electrodes, potentially allowing better targeting, electrode position revision, and the facilitation of functional imaging near electrodes during neuromodulation.
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Affiliation(s)
- Neeta Ashok Kumar
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, USA
| | - Munish Chauhan
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, USA
| | - Sri Kirthi Kandala
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, USA
| | - Sung-Min Sohn
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, USA
| | - Rosalind J Sadleir
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, USA
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Minhas AS, Chauhan M, Fu F, Sadleir R. Evaluation of magnetohydrodynamic effects in magnetic resonance electrical impedance tomography at ultra-high magnetic fields. Magn Reson Med 2018; 81:2264-2276. [PMID: 30450638 DOI: 10.1002/mrm.27534] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 08/25/2018] [Accepted: 08/27/2018] [Indexed: 11/09/2022]
Abstract
PURPOSE Artifacts observed in experimental magnetic resonance electrical impedance tomography images were hypothesized to be because of magnetohydrodynamic (MHD) effects. THEORY AND METHODS Simulations of MREIT acquisition in the presence of MHD and electrical current flow were performed to confirm findings. Laminar flow and (electrostatic) electrical conduction equations were bidirectionally coupled via Lorentz force equations, and finite element simulations were performed to predict flow velocity as a function of time. Gradient sequences used in spin-echo and gradient echo acquisitions were used to calculate overall effects on MR phase images for different electrical current application or phase-encoding directions. RESULTS Calculated and experimental phase images agreed relatively well, both qualitatively and quantitatively, with some exceptions. Refocusing pulses in spin echo sequences did not appear to affect experimental phase images. CONCLUSION MHD effects were confirmed as the cause of observed experimental phase changes in MREIT images obtained at high fields. These findings may have implications for quantitative measurement of viscosity using MRI techniques. Methods developed here may be also important in studies of safety and in vivo artifacts observed in high field MRI systems.
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Affiliation(s)
- Atul S Minhas
- Faculty of Science and Engineering, School of Engineering, Macquarie University, Sydney, NSW, Australia
| | - Munish Chauhan
- School of Biological and Health Systems Engineering, Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, Arizona
| | - Fanrui Fu
- School of Biological and Health Systems Engineering, Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, Arizona
| | - Rosalind Sadleir
- School of Biological and Health Systems Engineering, Ira A. Fulton Schools of Engineering, Arizona State University, Tempe, Arizona
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Schwartz BL, Chauhan M, Sadleir RJ. Analytic modeling of conductively anisotropic neural tissue. JOURNAL OF APPLIED PHYSICS 2018; 124:064701. [PMID: 30147144 PMCID: PMC6086692 DOI: 10.1063/1.5036659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/25/2018] [Indexed: 06/08/2023]
Abstract
The abdominal ganglion of the Aplysia californica is an established in vitro model for studying neuroelectric behavior in the presence of an applied electrical current and recently used in studies of magnetic resonance electrical impedance tomography (MREIT) which allows for quantitative visualization of spatially distributed current and magnetic flux densities. Understanding the impact the Aplysia geometry and anisotropic conductivity have on applied electromagnetic fields is central to intepreting and refining MREIT data and protocols, respectively. Here we present a simplified bidomain model of an in vitro experimental preparation of the Aplysia abdominal ganglion, describing the tissue as a radially anisotropic sphere with equal anisotropy ratios, i.e., where radial conductivities in both intra- and extra-cellular regions are ten times that of their polar and azimuthal conductivities. The fully three dimensional problem is validated through comparisons with limiting examples of 2D isotropic analyses. Results may be useful in validating finite element models of MREIT experiments and have broader relevance to analysis of MREIT data obtained from complex neural architecture in the human brain.
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Affiliation(s)
- Benjamin L Schwartz
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287-9709, USA
| | - Munish Chauhan
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287-9709, USA
| | - Rosalind J Sadleir
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287-9709, USA
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Sadleir RJ, Fu F, Chauhan M. Functional magnetic resonance electrical impedance tomography (fMREIT) sensitivity analysis using an active bidomain finite-element model of neural tissue. Magn Reson Med 2018; 81:602-614. [PMID: 29770490 DOI: 10.1002/mrm.27351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 04/06/2018] [Accepted: 04/17/2018] [Indexed: 11/07/2022]
Abstract
PURPOSE A direct method of imaging neural activity was simulated to determine typical signal sizes. METHODS An active bidomain finite-element model was used to estimate approximate perturbations in MR phase data as a result of neural tissue activity, and when an external MR electrical impedance tomography imaging current was added to the region containing neural current sources. RESULTS Modeling-predicted, activity-related conductivity changes should produce measurable differential phase signals in practical MR electrical impedance tomography experiments conducted at moderate resolution at noise levels typical of high field systems. The primary dependence of MR electrical impedance tomography phase contrast on membrane conductivity changes, and not source strength, was demonstrated. CONCLUSION Because the injected imaging current may also affect the level of activity in the tissue of interest, this technique can be used synergistically with neuromodulation techniques such as deep brain stimulation, to examine mechanisms of action.
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Affiliation(s)
- Rosalind J Sadleir
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona
| | - Fanrui Fu
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona
| | - Munish Chauhan
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona
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Fu F, Chauhan M, Sadleir R. The effect of potassium chloride on Aplysia Californica abdominal ganglion activity. Biomed Phys Eng Express 2018; 4. [PMID: 31367469 DOI: 10.1088/2057-1976/aab72e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Objective Spontaneous activity in the abdominal ganglion of Aplysia can be used as a convenient bioelectricity source in tests of novel MRI-based functional imaging methods, such as functional Magnetic Resonance Electrical Impedance Tomography (fMREIT). In these tests, it is necessary to find a consistent treatment that modulates neural activity, so that these results can be compared with control data. Effects of MREIT imaging currents combined with treatment were also of interest. Approach Potassium chloride (KCl) was employed as a rhythm modulator. In a series of experiments, effects of adding different volumes of KCl solution were tested and compared with experiments on control groups that had artificial sea water administered. In all cases, neuronal activity was measured with micro electrode arrays. Main results It was possible to reversibly stop spontaneous activity in ganglia by increasing the extracellular potassium chloride concentration to 89 mM. There was no effect on experimental outcomes when current was administered to the sample chamber between recordings. Significance KCl can be used as a reversible neural modulator for testing neural detection methods.
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Affiliation(s)
- Fanrui Fu
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ 85287, USA
| | - Munish Chauhan
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ 85287, USA
| | - Rosalind Sadleir
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ 85287, USA
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