A5008096297- Transcranial Magnetic Stimulation Studies
- Neuroscience and Neural Engineering
- Muscle activation and electromyography studies
- EEG and Brain-Computer Interfaces
- Photoreceptor and optogenetics research
- Neural dynamics and brain function
- Advanced DC-DC Converters
- Intraoperative Neuromonitoring and Anesthetic Effects
- Electrochemical Analysis and Applications
- Advanced Memory and Neural Computing
- Analytical Chemistry and Sensors
- Motor Control and Adaptation
- Pain Management and Treatment
- Neurobiology and Insect Physiology Research
- Multilevel Inverters and Converters
- Conducting polymers and applications
- Functional Brain Connectivity Studies
- Wireless Power Transfer Systems
- GaN-based semiconductor devices and materials
- Vestibular and auditory disorders
- Advanced Battery Technologies Research
- Advanced MRI Techniques and Applications
- HVDC Systems and Fault Protection
- Magnetic and transport properties of perovskites and related materials
- Physiological and biochemical adaptations
Duke University
2017-2025
Inner Mongolia University of Science and Technology
2025
University of Cambridge
2023
Duke University Hospital
2023
Duke Medical Center
2023
University of Southern California
2012-2015
Transcranial magnetic stimulation (TMS) enables non-invasive modulation of brain activity with both clinical and research applications, but fundamental questions remain about the neural types elements TMS activates how parameters affect response. To develop a multi-scale computational model to quantify effect on direct response individual neurons. We integrated morphologically-realistic neuronal models TMS-induced electric fields computed in finite element human head cortical several...
Abstract Implantable bioelectronic devices for the simulation of peripheral nerves could be used to treat disorders that are resistant traditional pharmacological therapies. However, many nerve targets, this requires invasive surgeries and implantation bulky (about a few centimetres in at least one dimension). Here we report design vivo proof-of-concept testing an endovascular wireless battery-free millimetric implant stimulation specific difficult reach via surgeries. The device can...
Temporal interference stimulation (TIS) was proposed as a non-invasive, focal, and steerable deep brain method. However, the mechanisms underlying experimentally-observed suprathreshold TIS effects are unknown, prior simulation studies had limitations in representations of electric field (E-field) cerebral neurons. We examined E-field neural response characteristics for related transcranial alternating current modalities.
Objective. To present a systematic framework and exemplar for the development of compact energy-efficient coil that replicates electric field (E-field) distribution induced by an existing transcranial magnetic stimulation coil. Approach. The E-field generated conventional low (LFMS) was measured spherical head model simulated in both realistic models. Then, using spatial harmonic decomposition, spherical-shaped cap synthesized such its windings conformed to surface replicated on cortical...
Transcranial magnetic stimulation (TMS) with monophasic pulses achieves greater changes in neuronal excitability but requires higher energy and generates more coil heating than TMS biphasic pulses, this limits the use of rapid-rate protocols. We sought to design a waveform that retains characteristics significantly reduces heating, thereby enabling pulse rates increased neuromodulation effectiveness.
Abstract Objective . Thresholding of neural responses is central to many applications transcranial magnetic stimulation (TMS), but the stochastic aspect neuronal activity and motor evoked potentials (MEPs) challenges thresholding techniques. We analyzed existing methods for obtaining TMS threshold their variations, introduced new from other fields, compared accuracy speed. Approach In addition relative-frequency methods, such as five-out-of-ten method, we examined adaptive based on a...
Objective. We present a theory and computational methods to incorporate transverse polarization of neuronal membranes into the cable equation account for secondary electric field generated by membrane in response fields. The effect on nonlinear activation thresholds is quantified discussed context previous studies using linear models. Approach. applied fields derived under two time scales unified solution given spherical cylindrical cell geometries. incorporated re-derived an asymptotic...
Objective.We present a combination of power electronics system and magnetic nanoparticles that enable frequency-multiplexed magnetothermal-neurostimulation with rapid channel switching between three independent channels spanning wide frequency range.Approach.The generates alternating field 50 kHz to 5 MHz in the same coil by combining silicon (Si) gallium-nitride (GaN) transistors resolve high spread impedance current required throughout bandwidth. The drives liquid-cooled via capacitor...
Modeling the electric field (E-field) on microscopic scale improves our understanding of brain stimulation modalities and modeling methods but requires careful consideration conductivity values correction amplitudes to match conventional models macroscopic scale. We analyze step discuss its relevance implications for E-field efforts bridging scales. provide theoretical framework comparing describe approaches effectively efficiently matching amplitude tissue conductivity. Consistent results...
Abstract Objective: Motor-evoked potentials (MEPs) in response to brain stimulation, such as transcranial magnetic stimulation (TMS), allow quantification of corticospinal excitability and have served the design almost all available neuromodulatory interventions. So-called thresholding MEPs at a point not too far above noise floor establishes reference for dosage safety. Despite fundamental importance distinguishing true from background noise, statistical properties are hardly known or...
Abstract Objective:
Spinal cord stimulation (SCS) models simulate the electric fields (E-fields) generated in targeted tissues, which turn govern physiological and then behavioral outcomes. Notwithstanding increasing sophistication adoption therapy optimization, SCS typically calculate E-fields using quasi-static approximation (QSA). QSA, as implemented neuromodulation models, neglects frequency-dependent tissue conductivity (dispersion), well propagation, capacitive, inductive...
Rectangular pulses applied to disk electrodes result in high current density at the edges of disk, which can lead electrode corrosion and tissue damage. We explored a method for reducing corrosion, by varying leading edge pulse. Finite-element modeling mathematical analysis were used predict an optimal waveform that reduces while also maintaining short pulse duration. An approximation optimized was implemented experimentally platinum electrodes. Surface using energy-dispersive spectroscopy...
Electrical impedance of the retina is a critical factor in retinal prostheses, determining intraretinal current flow and potential distribution electrical stimulation. Previous resistivity measurements were limited to healthy retina, didn't include mouse models, common important animal model research. This experimental study measured profiles wild-type, rd1, rd10 mice, providing basis for computational simulations predictive modeling studies. The peak resistance frequency method has been...
Gallium-nitride (GaN) transistors offer unparal-leled switching speed for power electronics, e.g., high-frequency applications or drastically reducing magnetics. Of par-ticular importance are the short-term overload capabilities of such circuits. Such is required most real-world with short-circuit risk, start-up currents, and a number emerging special in medi-cine as well scientific instrumentation. The compact packages lead-frame-free design typical GaN challenge thermal their transient...
Abstract Objective Thresholding of neural responses is central to many applications transcranial magnetic stimulation (TMS), but the stochastic aspect neuronal activity and motor evoked potentials (MEPs) challenges thresholding methods. We analyzed existing methods for obtaining TMS threshold their variations, introduced new from other fields, compared accuracy speed. Approach In addition relative-frequency methods, such as five-out-of-ten method, we examined adaptive based on a...