University of Minnesota
Department of Biomedical Engineering
http://www1.umn.edu/bme
612-624-4507

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Alexander Opitz

Alexander Opitz

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Summary of Research

My research focus is on the development of novel methods for non-invasive brain stimulation, including transcranial magnetic (TMS) and transcranial electric (TES) stimulation. I am particularly interested in the biophysical and physiological foundations of TMS and TES effects and how a better understanding of these can be translated into improved stimulation protocols in both research and clinical applications. In order to achieve these goals my lab uses a combination of modeling, experimentation and advanced data analysis techniques.

Focus Areas: Neural engineering, neuromodulation, computational modeling, neurophysiology, biomedical imaging.

Biophysical and neurophysiological mechanisms of TMS

I am investigating the biophysical mechanisms by which TMS operates and their impact on neurophysiology. I develop anatomically realistic finite element models to estimate the electric field distribution induced by TMS demonstrating the complexity of defining which brain areas are stimulated. In combination with neurophysiological recordings in healthy participants and patients, I am trying to understand which brain regions and neural elements are specifically activated by TMS.

Individualizing brain stimulation

Recent research has shown that the response to non-invasive brain stimulation (NIBS) methods can vary strongly across participants. I am trying to identify individual anatomical and functional predictors for the response to NIBS. For that purpose, I am working on developing individualized stimulation protocols in the hope of improving the response to NIBS protocols.

Biophysics of TES and development of improved stimulation protocols

TES is an increasingly popular form of NIBS due to its ease of application and low cost. However, many open questions exist with the respect of effective dosing and optimal application. I am working on developing an improved understanding of the biophysical foundations of TES and how this can be translated in an improved stimulation protocols.

Selected Publications

Opitz A, Falchier A, Yan CG, Yeagle E, Linn G, Megevand P, Thielscher A, Ross DA, Milham MP, Mehta A, Schroeder C (2016) Spatiotemporal structure of intracranial electric fields induced by transcranial electric stimulation in humans and nonhuman primates. Scientific reports 6: 31236.

Opitz A, Fox MD, Craddock RC, Colcombe S, Milham MP (2016) An integrated framework for targeting functional networks via transcranial magnetic stimulation. NeuroImage 127: 86-96.

Opitz A, Paulus W, Will S, Antunes A, Thielscher A (2015) Anatomical determinants of the electric field during transcranial direct current stimulation. NeuroImage 109:140-159.

Opitz A, Zafar N, Bockermann V, Rohde V, Paulus W. (2014) Validating computationally predicted TMS stimulation areas using direct electrical stimulation in patients with brain tumors near precentral regions. Neuroimage: Clinical 4:500-507.

Opitz A, Legon W, Rowlands A, Bickel WK, Paulus W, Tyler WJ (2013) Physiological observations validate finite element models for estimating subject-specific electric field distributions induced by transcranial magnetic stimulation of the human motor cortex. NeuroImage 81:253-264.

Windhoff M, Opitz A, Thielscher A (2013) Electric field calculations in brain stimulation based on finite elements: an optimized processing pipeline for the generation and usage of accurate individual head models. Hum Brain Mapping 34:923-935.

Opitz A, Windhoff M, Heidemann RM, Turner R, Thielscher A (2011) How the brain tissue shapes the electric field induced by transcranial magnetic stimulation. NeuroImage 58:849-859.