1
|
Lee JI, Werginz P, Kameneva T, Im M, Fried SI. Membrane depolarization mediates both the inhibition of neural activity and cell-type-differences in response to high-frequency stimulation. Commun Biol 2024; 7:734. [PMID: 38890481 PMCID: PMC11189419 DOI: 10.1038/s42003-024-06359-3] [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: 03/16/2023] [Accepted: 05/20/2024] [Indexed: 06/20/2024] Open
Abstract
Neuromodulation using high frequency (>1 kHz) electric stimulation (HFS) enables preferential activation or inhibition of individual neural types, offering the possibility of more effective treatments across a broad spectrum of neurological diseases. To improve effectiveness, it is important to better understand the mechanisms governing activation and inhibition with HFS so that selectivity can be optimized. In this study, we measure the membrane potential (Vm) and spiking responses of ON and OFF α-sustained retinal ganglion cells (RGCs) to a wide range of stimulus frequencies (100-2500 Hz) and amplitudes (10-100 µA). Our findings indicate that HFS induces shifts in Vm, with both the strength and polarity of the shifts dependent on the stimulus conditions. Spiking responses in each cell directly correlate with the shifts in Vm, where strong depolarization leads to spiking suppression. Comparisons between the two cell types reveal that ON cells are more depolarized by a given amplitude of HFS than OFF cells-this sensitivity difference enables the selective targeting. Computational modeling indicates that ion-channel dynamics largely account for the shifts in Vm, suggesting that a better understanding of the differences in ion-channel properties across cell types may improve the selectivity and ultimately, enhance HFS-based neurostimulation strategies.
Collapse
Affiliation(s)
- Jae-Ik Lee
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Paul Werginz
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Institute of Biomedical Electronics, TU Wien, Vienna, Austria
| | - Tatiana Kameneva
- School of Science, Computing, and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, Australia
| | - Maesoon Im
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea
- Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology (UST), Seoul, South Korea
- KHU-KIST Department of Converging Science and Technology, Kyung Hee University, Seoul, Republic of Korea
| | - Shelley I Fried
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Boston VA Healthcare System, Rehabilitation, Research and Development, Boston, MA, USA
| |
Collapse
|
2
|
Sessler CD, Zhou Y, Wang W, Hartley ND, Fu Z, Graykowski D, Sheng M, Wang X, Liu J. Optogenetic polymerization and assembly of electrically functional polymers for modulation of single-neuron excitability. SCIENCE ADVANCES 2022; 8:eade1136. [PMID: 36475786 PMCID: PMC9728971 DOI: 10.1126/sciadv.ade1136] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 10/28/2022] [Indexed: 06/17/2023]
Abstract
Ionic conductivity and membrane capacitance are two foundational parameters that govern neuron excitability. Conventional optogenetics has emerged as a powerful tool to temporarily manipulate membrane ionic conductivity in intact biological systems. However, no analogous method exists for precisely manipulating cell membrane capacitance to enable long-lasting modulation of neuronal excitability. Genetically targetable chemical assembly of conductive and insulating polymers can modulate cell membrane capacitance, but further development of this technique has been hindered by poor spatiotemporal control of the polymer deposition and cytotoxicity from the widely diffused peroxide. We address these issues by harnessing genetically targetable photosensitizer proteins to assemble electrically functional polymers in neurons with precise spatiotemporal control. Using whole-cell patch-clamp recordings, we demonstrate that this optogenetic polymerization can achieve stepwise modulation of both neuron membrane capacitance and intrinsic excitability. Furthermore, cytotoxicity can be limited by controlling light exposure, demonstrating a promising new method for precisely modulating cell excitability.
Collapse
Affiliation(s)
- Chanan D. Sessler
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Yiming Zhou
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Wenbo Wang
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Nolan D. Hartley
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Zhanyan Fu
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - David Graykowski
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Morgan Sheng
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Xiao Wang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Jia Liu
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| |
Collapse
|
3
|
Cerpa E, Courdurier M, Hernández E, Medina LE, Paduro E. A partially averaged system to model neuron responses to interferential current stimulation. J Math Biol 2022; 86:8. [PMID: 36469157 DOI: 10.1007/s00285-022-01839-8] [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: 05/22/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 12/12/2022]
Abstract
The interferential current (IFC) therapy is a noninvasive electrical neurostimulation technique intended to activate deep neurons using surface electrodes. In IFC, two independent kilohertz-frequency currents purportedly intersect where an interference field is generated. However, the effects of IFC on neurons within and outside the interference field are not completely understood, and it is unclear whether this technique can reliable activate deep target neurons without side effects. In recent years, realistic computational models of IFC have been introduced to quantify the effects of IFC on brain cells, but they are often complex and computationally costly. Here, we introduce a simplified model of IFC based on the FitzHugh-Nagumo (FHN) model of a neuron. By considering a modified averaging method, we obtain a non-autonomous approximated system, with explicit representation of relevant IFC parameters. For this approximated system we determine conditions under which it reliably approximates the complete FHN system under IFC stimulation, and we mathematically prove its ability to predict nonspiking states. In addition, we perform numerical simulations that show that the interference effect is observed only for a narrow set of IFC parameters and, in particular, for a beat frequency no higher than about 100 [Hz]. Our novel model tailored to the IFC technique contributes to the understanding of neurostimulation modalities using this type of signals, and can have implications in the design of noninvasive electrical stimulation therapies.
Collapse
Affiliation(s)
- Eduardo Cerpa
- Facultad de Matemáticas, Instituto de Ingeniería Matemática y Computacional, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna 4860, Macul, Santiago, 7820436, Chile.,Millennium Nucleus for Applied Control and Inverse Problems, Santiago, Chile
| | - Matías Courdurier
- Departamento de Matemática, Facultad de Matemáticas, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna 4860, Macul, Santiago, 7820436, Chile.,Millennium Nucleus for Applied Control and Inverse Problems, Santiago, Chile
| | - Esteban Hernández
- Departamento de Matemática, Universidad Técnica Federico Santa María, Avda. España 1680, Valparaíso, 2390123, Chile
| | - Leonel E Medina
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Avda. Víctor Jara 3659, Estación Central, Santiago, 9170124, Chile.,Millennium Nucleus for Applied Control and Inverse Problems, Santiago, Chile
| | - Esteban Paduro
- Facultad de Matemáticas, Instituto de Ingeniería Matemática y Computacional, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna 4860, Macul, Santiago, 7820436, Chile. .,Millennium Nucleus for Applied Control and Inverse Problems, Santiago, Chile.
| |
Collapse
|
4
|
Mokhtare A, Davaji B, Xie P, Yaghoobi M, Rosenwaks Z, Lal A, Palermo G, Abbaspourrad A. Non-contact ultrasound oocyte denudation. LAB ON A CHIP 2022; 22:777-792. [PMID: 35075469 DOI: 10.1039/d1lc00715g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cumulus removal (CR) is a central prerequisite step for many protocols involved in the assisted reproductive technology (ART) such as intracytoplasmic sperm injection (ICSI) and preimplantation genetic testing (PGT). The most prevalent CR technique is based upon laborious manual pipetting, which suffers from inter-operator variability and therefore a lack of standardization. Automating CR procedures would alleviate many of these challenges, improving the odds of a successful ART or PGT outcome. In this study, a chip-scale ultrasonic device consisting of four interdigitated transducers (IDT) on a lithium niobate substrate has been engineered to deliver megahertz (MHz) range ultrasound to perform denudation. The acoustic streaming and acoustic radiation force agitate COCs inside a microwell placed on top of the LiNbO3 substrate to remove the cumulus cells from the oocytes. This paper demonstrates the capability and safety of the denudation procedure utilizing surface acoustic wave (SAW), achieving automation of this delicate manual procedure and paving the steps toward improved and standardized oocyte manipulation.
Collapse
Affiliation(s)
- Amir Mokhtare
- Department of Food Science, Cornell University, Stocking Hall, Ithaca, NY, 14853, USA.
| | - Benyamin Davaji
- School of Electrical and Computer Engineering, Cornell University, Ithaca, NY, USA
| | - Philip Xie
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Mohammad Yaghoobi
- Department of Food Science, Cornell University, Stocking Hall, Ithaca, NY, 14853, USA.
| | - Zev Rosenwaks
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Amit Lal
- School of Electrical and Computer Engineering, Cornell University, Ithaca, NY, USA
| | - Gianpiero Palermo
- The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Alireza Abbaspourrad
- Department of Food Science, Cornell University, Stocking Hall, Ithaca, NY, 14853, USA.
| |
Collapse
|
5
|
Neudorfer C, Chow CT, Boutet A, Loh A, Germann J, Elias GJ, Hutchison WD, Lozano AM. Kilohertz-frequency stimulation of the nervous system: A review of underlying mechanisms. Brain Stimul 2021; 14:513-530. [PMID: 33757930 DOI: 10.1016/j.brs.2021.03.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 03/08/2021] [Accepted: 03/11/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Electrical stimulation in the kilohertz-frequency range has gained interest in the field of neuroscience. The mechanisms underlying stimulation in this frequency range, however, are poorly characterized to date. OBJECTIVE/HYPOTHESIS To summarize the manifold biological effects elicited by kilohertz-frequency stimulation in the context of the currently existing literature and provide a mechanistic framework for the neural responses observed in this frequency range. METHODS A comprehensive search of the peer-reviewed literature was conducted across electronic databases. Relevant computational, clinical, and mechanistic studies were selected for review. RESULTS The effects of kilohertz-frequency stimulation on neural tissue are diverse and yield effects that are distinct from conventional stimulation. Broadly, these can be divided into 1) subthreshold, 2) suprathreshold, 3) synaptic and 4) thermal effects. While facilitation is the dominating mechanism at the subthreshold level, desynchronization, spike-rate adaptation, conduction block, and non-monotonic activation can be observed during suprathreshold kilohertz-frequency stimulation. At the synaptic level, kilohertz-frequency stimulation has been associated with the transient depletion of the available neurotransmitter pool - also known as synaptic fatigue. Finally, thermal effects associated with extrinsic (environmental) and intrinsic (associated with kilohertz-frequency stimulation) temperature changes have been suggested to alter the neural response to stimulation paradigms. CONCLUSION The diverse spectrum of neural responses to stimulation in the kilohertz-frequency range is distinct from that associated with conventional stimulation. This offers the potential for new therapeutic avenues across stimulation modalities. However, stimulation in the kilohertz-frequency range is associated with distinct challenges and caveats that need to be considered in experimental paradigms.
Collapse
Affiliation(s)
- Clemens Neudorfer
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - Clement T Chow
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - Alexandre Boutet
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - Aaron Loh
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - Jürgen Germann
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - Gavin Jb Elias
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada
| | - William D Hutchison
- Krembil Research Institute, University of Toronto, Ontario, Canada; Department of Physiology, Toronto Western Hospital and University of Toronto, Ontario, Canada
| | - Andres M Lozano
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Canada; Krembil Research Institute, University of Toronto, Ontario, Canada.
| |
Collapse
|
6
|
Marya A, Venugopal A. The Use of Technology in the Management of Orthodontic Treatment-Related Pain. Pain Res Manag 2021; 2021:5512031. [PMID: 33763158 PMCID: PMC7964123 DOI: 10.1155/2021/5512031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/10/2021] [Accepted: 03/02/2021] [Indexed: 11/17/2022]
Abstract
Orthodontic pain is one of the negatives associated with fixed orthodontic treatment that cannot be avoided. This pain usually comes around the wire placement period and gradually decreases once the endogenous analgesic mechanisms start functioning. Over the years, several treatment modalities have been utilized for relief from orthodontic pain, and these include mechanical, behavior modification, and pharmacological methods. However, in the last decade, there are several newer methods employing the use of technology that have come up and are being used for alleviating pain. From computerized indirect bonding to virtual treatment planning, technology has slowly become a vital part of an orthodontist's repertoire. The digital age is here, and orthodontics must embrace the use of technology to help improve the quality of life of patients.
Collapse
Affiliation(s)
- Anand Marya
- Department of Orthodontics, University of Puthisastra, Phnom Penh, Cambodia
| | - Adith Venugopal
- Department of Orthodontics, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| |
Collapse
|
7
|
Li SJ, Lo YC, Lai HY, Lin SH, Lin HC, Lin TC, Chang CW, Chen TC, Chin-Jung Hsieh C, Yang SH, Chiu FM, Kuo CH, Chen YY. Uncovering the Modulatory Interactions of Brain Networks in Cognition with Central Thalamic Deep Brain Stimulation Using Functional Magnetic Resonance Imaging. Neuroscience 2020; 440:65-84. [DOI: 10.1016/j.neuroscience.2020.05.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 05/05/2020] [Accepted: 05/12/2020] [Indexed: 01/04/2023]
|
8
|
GHz Ultrasonic Chip-Scale Device Induces Ion Channel Stimulation in Human Neural Cells. Sci Rep 2020; 10:3075. [PMID: 32080204 PMCID: PMC7033194 DOI: 10.1038/s41598-020-58133-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/10/2020] [Indexed: 01/07/2023] Open
Abstract
Emergent trends in the device development for neural prosthetics have focused on establishing stimulus localization, improving longevity through immune compatibility, reducing energy re-quirements, and embedding active control in the devices. Ultrasound stimulation can single-handedly address several of these challenges. Ultrasonic stimulus of neurons has been studied extensively from 100 kHz to 10 MHz, with high penetration but less localization. In this paper, a chip-scale device consisting of piezoelectric Aluminum Nitride ultrasonic transducers was engineered to deliver gigahertz (GHz) ultrasonic stimulus to the human neural cells. These devices provide a path towards complementary metal oxide semiconductor (CMOS) integration towards fully controllable neural devices. At GHz frequencies, ultrasonic wavelengths in water are a few microns and have an absorption depth of 10-20 µm. This confinement of energy can be used to control stimulation volume within a single neuron. This paper is the first proof-of-concept study to demonstrate that GHz ultrasound can stimulate neurons in vitro. By utilizing optical calcium imaging, which records calcium ion flux indicating occurrence of an action potential, this paper demonstrates that an application of a nontoxic dosage of GHz ultrasonic waves [Formula: see text] caused an average normalized fluorescence intensity recordings >1.40 for the calcium transients. Electrical effects due to chip-scale ultrasound delivery was discounted as the sole mechanism in stimulation, with effects tested at α = 0.01 statistical significance amongst all intensities and con-trol groups. Ionic transients recorded optically were confirmed to be mediated by ion channels and experimental data suggests an insignificant thermal contributions to stimulation, with a predicted increase of 0.03 oC for [Formula: see text] This paper paves the experimental framework to further explore chip-scale axon and neuron specific neural stimulation, with future applications in neural prosthetics, chip scale neural engineering, and extensions to different tissue and cell types.
Collapse
|
9
|
Couto J, Grill WM. Kilohertz Frequency Deep Brain Stimulation Is Ineffective at Regularizing the Firing of Model Thalamic Neurons. Front Comput Neurosci 2016; 10:22. [PMID: 27014047 PMCID: PMC4791372 DOI: 10.3389/fncom.2016.00022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 02/29/2016] [Indexed: 01/24/2023] Open
Abstract
Deep brain stimulation (DBS) is an established therapy for movement disorders, including tremor, dystonia, and Parkinson's disease, but the mechanisms of action are not well understood. Symptom suppression by DBS typically requires stimulation frequencies ≥100 Hz, but when the frequency is increased above ~2 kHz, the effectiveness in tremor suppression declines (Benabid et al., 1991). We sought to test the hypothesis that the decline in efficacy at high frequencies is associated with desynchronization of the activity generated within a population of stimulated neurons. Regularization of neuronal firing is strongly correlated with tremor suppression by DBS, and desynchronization would disrupt the regularization of neuronal activity. We implemented computational models of CNS axons with either deterministic or stochastic membrane dynamics, and quantified the response of populations of model nerve fibers to extracellular stimulation at different frequencies and amplitudes. As stimulation frequency was increased from 2 to 80 Hz the regularity of neuronal firing increased (as assessed with direct estimates of entropy), in accord with the clinical effects on tremor of increasing stimulation frequency (Kuncel et al., 2006). Further, at frequencies between 80 and 500 Hz, increasing the stimulation amplitude (i.e., the proportion of neurons activated by the stimulus) increased the regularity of neuronal activity across the population, in accord with the clinical effects on tremor of stimulation amplitude (Kuncel et al., 2007). However, at stimulation frequencies above 1 kHz the regularity of neuronal firing declined due to irregular patterns of action potential generation and conduction block. The reductions in neuronal regularity that occurred at high frequencies paralleled the previously reported decline in tremor reduction and may be responsible for the loss of efficacy of DBS at very high frequencies. This analysis provides further support for the hypothesis that effective DBS masks the intrinsic patterns of activity in the stimulated neurons and replaces it with regularized firing.
Collapse
Affiliation(s)
- João Couto
- Department of Biomedical Engineering, Duke UniversityDurham, NC, USA; Theoretical Neurobiology and Neuroengineering Laboratory, Department of Biomedical Engineering, University of AntwerpAntwerp, Belgium
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University Durham, NC, USA
| |
Collapse
|
10
|
Weinberg SH. Membrane capacitive memory alters spiking in neurons described by the fractional-order Hodgkin-Huxley model. PLoS One 2015; 10:e0126629. [PMID: 25970534 PMCID: PMC4430543 DOI: 10.1371/journal.pone.0126629] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 04/04/2015] [Indexed: 12/17/2022] Open
Abstract
Excitable cells and cell membranes are often modeled by the simple yet elegant parallel resistor-capacitor circuit. However, studies have shown that the passive properties of membranes may be more appropriately modeled with a non-ideal capacitor, in which the current-voltage relationship is given by a fractional-order derivative. Fractional-order membrane potential dynamics introduce capacitive memory effects, i.e., dynamics are influenced by a weighted sum of the membrane potential prior history. However, it is not clear to what extent fractional-order dynamics may alter the properties of active excitable cells. In this study, we investigate the spiking properties of the neuronal membrane patch, nerve axon, and neural networks described by the fractional-order Hodgkin-Huxley neuron model. We find that in the membrane patch model, as fractional-order decreases, i.e., a greater influence of membrane potential memory, peak sodium and potassium currents are altered, and spike frequency and amplitude are generally reduced. In the nerve axon, the velocity of spike propagation increases as fractional-order decreases, while in a neural network, electrical activity is more likely to cease for smaller fractional-order. Importantly, we demonstrate that the modulation of the peak ionic currents that occurs for reduced fractional-order alone fails to reproduce many of the key alterations in spiking properties, suggesting that membrane capacitive memory and fractional-order membrane potential dynamics are important and necessary to reproduce neuronal electrical activity.
Collapse
Affiliation(s)
- Seth H. Weinberg
- Virginia Modeling, Analysis and Simulation Center, Old Dominion University, 1030 University Boulevard, Suffolk, Virginia, USA
- * E-mail:
| |
Collapse
|
11
|
Weinberg SH. High frequency stimulation of cardiac myocytes: a theoretical and computational study. CHAOS (WOODBURY, N.Y.) 2014; 24:043104. [PMID: 25554024 DOI: 10.1063/1.4897618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
High-frequency stimulation (HFS) has recently been identified as a novel approach for terminating life-threatening cardiac arrhythmias. HFS elevates myocyte membrane potential and blocks electrical conduction for the duration of the stimulus. However, low amplitude HFS can induce rapidly firing action potentials, which may reinitiate an arrhythmia. The cellular level mechanisms underlying HFS-induced electrical activity are not well understood. Using a multiscale method, we show that a minimal myocyte model qualitatively reproduces the influence of HFS on cardiac electrical activity. Theoretical analysis and simulations suggest that persistent activation and de-inactivation of ionic currents, in particular a fast inward window current, underlie HFS-induced action potentials and membrane potential elevation, providing hypotheses for future experiments. We derive analytical expressions to describe how HFS modifies ionic current amplitude and gating dynamics. We show how fast inward current parameters influence the parameter regimes for HFS-induced electrical activity, demonstrating how the efficacy of HFS as a therapy for terminating arrhythmias may depend on the presence of pathological conditions or pharmacological treatments. Finally, we demonstrate that HFS terminates cardiac arrhythmias in a one-dimensional ring of cardiac tissue. In this study, we demonstrate a novel approach to characterize the influence of HFS on ionic current gating dynamics, provide new insight into HFS of the myocardium, and suggest mechanisms underlying HFS-induced electrical activity.
Collapse
Affiliation(s)
- Seth H Weinberg
- Virginia Modeling, Analysis and Simulation Center, Old Dominion University, Suffolk, Virginia 23435, USA
| |
Collapse
|