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Johnson KA, Dosenbach NUF, Gordon EM, Welle CG, Wilkins KB, Bronte-Stewart HM, Voon V, Morishita T, Sakai Y, Merner AR, Lázaro-Muñoz G, Williamson T, Horn A, Gilron R, O'Keeffe J, Gittis AH, Neumann WJ, Little S, Provenza NR, Sheth SA, Fasano A, Holt-Becker AB, Raike RS, Moore L, Pathak YJ, Greene D, Marceglia S, Krinke L, Tan H, Bergman H, Pötter-Nerger M, Sun B, Cabrera LY, McIntyre CC, Harel N, Mayberg HS, Krystal AD, Pouratian N, Starr PA, Foote KD, Okun MS, Wong JK. Proceedings of the 11th Annual Deep Brain Stimulation Think Tank: pushing the forefront of neuromodulation with functional network mapping, biomarkers for adaptive DBS, bioethical dilemmas, AI-guided neuromodulation, and translational advancements. Front Hum Neurosci 2024; 18:1320806. [PMID: 38450221 PMCID: PMC10915873 DOI: 10.3389/fnhum.2024.1320806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 02/05/2024] [Indexed: 03/08/2024] Open
Abstract
The Deep Brain Stimulation (DBS) Think Tank XI was held on August 9-11, 2023 in Gainesville, Florida with the theme of "Pushing the Forefront of Neuromodulation". The keynote speaker was Dr. Nico Dosenbach from Washington University in St. Louis, Missouri. He presented his research recently published in Nature inn a collaboration with Dr. Evan Gordon to identify and characterize the somato-cognitive action network (SCAN), which has redefined the motor homunculus and has led to new hypotheses about the integrative networks underpinning therapeutic DBS. The DBS Think Tank was founded in 2012 and provides an open platform where clinicians, engineers, and researchers (from industry and academia) can freely discuss current and emerging DBS technologies, as well as logistical and ethical issues facing the field. The group estimated that globally more than 263,000 DBS devices have been implanted for neurological and neuropsychiatric disorders. This year's meeting was focused on advances in the following areas: cutting-edge translational neuromodulation, cutting-edge physiology, advances in neuromodulation from Europe and Asia, neuroethical dilemmas, artificial intelligence and computational modeling, time scales in DBS for mood disorders, and advances in future neuromodulation devices.
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Affiliation(s)
- Kara A. Johnson
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
- Department of Neurology, University of Florida, Gainesville, FL, United States
| | - Nico U. F. Dosenbach
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, United States
| | - Evan M. Gordon
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Cristin G. Welle
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, United States
- Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO, United States
| | - Kevin B. Wilkins
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, United States
| | - Helen M. Bronte-Stewart
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, United States
| | - Valerie Voon
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
| | - Takashi Morishita
- Department of Neurosurgery, Fukuoka University Faculty of Medicine, Fukuoka, Japan
| | - Yuki Sakai
- ATR Brain Information Communication Research Laboratory Group, Kyoto, Japan
- Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Amanda R. Merner
- Center for Bioethics, Harvard Medical School, Boston, MA, United States
| | - Gabriel Lázaro-Muñoz
- Center for Bioethics, Harvard Medical School, Boston, MA, United States
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, United States
| | - Theresa Williamson
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, United States
| | - Andreas Horn
- Department of Neurology, Center for Brain Circuit Therapeutics, Harvard Medical School, Brigham & Women's Hospital, Boston, MA, United States
- MGH Neurosurgery and Center for Neurotechnology and Neurorecovery (CNTR) at MGH Neurology Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
- Movement Disorder and Neuromodulation Unit, Department of Neurology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt- Universität zu Berlin, Berlin, Germany
| | | | | | - Aryn H. Gittis
- Biological Sciences and Center for Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Wolf-Julian Neumann
- Movement Disorder and Neuromodulation Unit, Department of Neurology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt- Universität zu Berlin, Berlin, Germany
| | - Simon Little
- Department of Neurological Surgery, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - Nicole R. Provenza
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, United States
| | - Sameer A. Sheth
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, United States
| | - Alfonso Fasano
- Edmond J. Safra Program in Parkinson's Disease, Division of Neurology, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, University Health Network (UHN), University of Toronto, Toronto, ON, Canada
- Krembil Brain Institute, Toronto, ON, Canada
| | - Abbey B. Holt-Becker
- Restorative Therapies Group Implantables, Research, and Core Technology, Medtronic Inc., Minneapolis, MN, United States
| | - Robert S. Raike
- Restorative Therapies Group Implantables, Research, and Core Technology, Medtronic Inc., Minneapolis, MN, United States
| | - Lisa Moore
- Boston Scientific Neuromodulation Corporation, Valencia, CA, United States
| | | | - David Greene
- NeuroPace, Inc., Mountain View, CA, United States
| | - Sara Marceglia
- Department of Engineering and Architecture, University of Trieste, Trieste, Italy
| | - Lothar Krinke
- Newronika SPA, Milan, Italy
- Department of Neuroscience, West Virginia University, Morgantown, WV, United States
| | - Huiling Tan
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Hagai Bergman
- Edmond and Lily Safar Center (ELSC) for Brain Research and Department of Medical Neurobiology (Physiology), Institute of Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Neurosurgery, Hadassah Medical Center, Jerusalem, Israel
| | - Monika Pötter-Nerger
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Bomin Sun
- Department of Neurosurgery, Center for Functional Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Laura Y. Cabrera
- Neuroethics, Department of Engineering Science and Mechanics, Philosophy, and Bioethics, and the Rock Ethics Institute, Pennsylvania State University, State College, PA, United States
| | - Cameron C. McIntyre
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
- Department of Neurosurgery, Duke University, Durham, NC, United States
| | - Noam Harel
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States
| | - Helen S. Mayberg
- Department of Neurology, Neurosurgery, Psychiatry, and Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Andrew D. Krystal
- Departments of Psychiatry and Behavioral Science and Neurology, University of California, San Francisco, San Francisco, CA, United States
| | - Nader Pouratian
- Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Philip A. Starr
- Department of Neurological Surgery, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
| | - Kelly D. Foote
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
- Department of Neurosurgery, University of Florida, Gainesville, FL, United States
| | - Michael S. Okun
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
- Department of Neurology, University of Florida, Gainesville, FL, United States
| | - Joshua K. Wong
- Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
- Department of Neurology, University of Florida, Gainesville, FL, United States
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Kumar V, Behrman K, Speed F, Saladrigas CA, Supekar O, Huang Z, Bright VM, Welle CG, Restrepo D, Gopinath JT, Gibson EA, Kymissis I. MicroLED light source for optical sectioning structured illumination microscopy. Opt Express 2023; 31:16709-16718. [PMID: 37157744 PMCID: PMC10316754 DOI: 10.1364/oe.486754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/14/2023] [Accepted: 04/19/2023] [Indexed: 05/10/2023]
Abstract
Optical sectioning structured illumination microscopy (OS-SIM) provides optical sectioning capability in wide-field microscopy. The required illumination patterns have traditionally been generated using spatial light modulators (SLM), laser interference patterns, or digital micromirror devices (DMDs) which are too complex to implement in miniscope systems. MicroLEDs have emerged as an alternative light source for patterned illumination due to their extreme brightness capability and small emitter sizes. This paper presents a directly addressable striped microLED microdisplay with 100 rows on a flexible cable (70 cm long) for use as an OS-SIM light source in a benchtop setup. The overall design of the microdisplay is described in detail with luminance-current-voltage characterization. OS-SIM implementation with a benchtop setup shows the optical sectioning capability of the system by imaging within a 500 µm thick fixed brain slice from a transgenic mouse where oligodendrocytes are labeled with a green fluorescent protein (GFP). Results show improved contrast in reconstructed optically sectioned images of 86.92% (OS-SIM) compared with 44.31% (pseudo-widefield). MicroLED based OS-SIM therefore offers a new capability for deep tissue widefield imaging.
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Affiliation(s)
| | | | - Forest Speed
- University of Colorado Anschutz, Aurora, CO 80045, USA
| | | | - Omkar Supekar
- University of Colorado Boulder, Boulder, CO 80309, USA
| | - Zicong Huang
- Columbia University, New York City, NY 10027, USA
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Ye M, Zestos AG, Welle CG, Wu GK, Cui XT. Editorial: Safety and efficacy evaluation of electrical stimulation devices for neural modulation. Front Neurosci 2023; 17:1143989. [PMID: 36824215 PMCID: PMC9941729 DOI: 10.3389/fnins.2023.1143989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 01/25/2023] [Indexed: 02/10/2023] Open
Affiliation(s)
- Meijun Ye
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, United States
| | - Alexander G Zestos
- Department of Chemistry, American University, Washington, DC, United States
| | - Cristin G Welle
- Department of Physiology and Biophysics, University of Colorado, Anschutz Medical Campus, Denver, CO, United States
| | - Guangying K Wu
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States
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Bowles S, Hickman J, Peng X, Williamson WR, Huang R, Washington K, Donegan D, Welle CG. Vagus nerve stimulation drives selective circuit modulation through cholinergic reinforcement. Neuron 2022; 110:2867-2885.e7. [PMID: 35858623 DOI: 10.1016/j.neuron.2022.06.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 04/22/2022] [Accepted: 06/17/2022] [Indexed: 12/23/2022]
Abstract
Vagus nerve stimulation (VNS) is a neuromodulation therapy for a broad and expanding set of neurologic conditions. However, the mechanism through which VNS influences central nervous system circuitry is not well described, limiting therapeutic optimization. VNS leads to widespread brain activation, but the effects on behavior are remarkably specific, indicating plasticity unique to behaviorally engaged neural circuits. To understand how VNS can lead to specific circuit modulation, we leveraged genetic tools including optogenetics and in vivo calcium imaging in mice learning a skilled reach task. We find that VNS enhances skilled motor learning in healthy animals via a cholinergic reinforcement mechanism, producing a rapid consolidation of an expert reach trajectory. In primary motor cortex (M1), VNS drives precise temporal modulation of neurons that respond to behavioral outcome. This suggests that VNS may accelerate motor refinement in M1 via cholinergic signaling, opening new avenues for optimizing VNS to target specific disease-relevant circuitry.
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Affiliation(s)
- Spencer Bowles
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA; Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jordan Hickman
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Xiaoyu Peng
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA; Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - W Ryan Williamson
- IDEA Core, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Rongchen Huang
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA; Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Kayden Washington
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA; Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Dane Donegan
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA; Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Cristin G Welle
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA; Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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Supekar OD, Sias A, Hansen SR, Martinez G, Peet GC, Peng X, Bright VM, Hughes EG, Restrepo D, Shepherd DP, Welle CG, Gopinath JT, Gibson EA. Miniature structured illumination microscope for in vivo 3D imaging of brain structures with optical sectioning. Biomed Opt Express 2022; 13:2530-2541. [PMID: 35519247 PMCID: PMC9045919 DOI: 10.1364/boe.449533] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/26/2022] [Accepted: 03/05/2022] [Indexed: 05/25/2023]
Abstract
We present a high-resolution miniature, light-weight fluorescence microscope with electrowetting lens and onboard CMOS for high resolution volumetric imaging and structured illumination for rejection of out-of-focus and scattered light. The miniature microscope (SIMscope3D) delivers structured light using a coherent fiber bundle to obtain optical sectioning with an axial resolution of 18 µm. Volumetric imaging of eGFP labeled cells in fixed mouse brain tissue at depths up to 260 µm is demonstrated. The functionality of SIMscope3D to provide background free 3D imaging is shown by recording time series of microglia dynamics in awake mice at depths up to 120 µm in the brain.
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Affiliation(s)
- Omkar D Supekar
- Department of Electrical, Energy and Computer Engineering, University of Colorado Boulder, CO 80309, USA
- Department of Mechanical Engineering, University of Colorado Boulder, CO 80309, USA
| | - Andrew Sias
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, CO 80045, USA
| | - Sean R Hansen
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, CO 80045, USA
| | - Gabriel Martinez
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, CO 80045, USA
| | - Graham C Peet
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, CO 80045, USA
| | - Xiaoyu Peng
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, CO 80045, USA
| | - Victor M Bright
- Department of Mechanical Engineering, University of Colorado Boulder, CO 80309, USA
| | - Ethan G Hughes
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, CO 80045, USA
| | - Diego Restrepo
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, CO 80045, USA
| | | | - Cristin G Welle
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, CO 80045, USA
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, CO 80045, USA
| | - Juliet T Gopinath
- Department of Electrical, Energy and Computer Engineering, University of Colorado Boulder, CO 80309, USA
- Department of Physics, University of Colorado Boulder, CO 80309, USA
| | - Emily A Gibson
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, CO 80045, USA
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Bowles S, Williamson WR, Nettles D, Hickman J, Welle CG. Closed-loop automated reaching apparatus (CLARA) for interrogating complex motor behaviors. J Neural Eng 2021; 18:10.1088/1741-2552/ac1ed1. [PMID: 34407518 PMCID: PMC8699662 DOI: 10.1088/1741-2552/ac1ed1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 08/18/2021] [Indexed: 11/11/2022]
Abstract
Objective.Closed-loop neuromodulation technology is a rapidly expanding category of therapeutics for a broad range of indications. Development of these innovative neurological devices requires high-throughput systems for closed-loop stimulation of model organisms, while monitoring physiological signals and complex, naturalistic behaviors. To address this need, we developed CLARA, a closed-loop automated reaching apparatus.Approach.Using breakthroughs in computer vision, CLARA integrates fully-automated, markerless kinematic tracking of multiple features to classify animal behavior and precisely deliver neural stimulation based on behavioral outcomes. CLARA is compatible with advanced neurophysiological tools, enabling the testing of neurostimulation devices and identification of novel neurological biomarkers.Results.The CLARA system tracks unconstrained skilled reach behavior in 3D at 150 Hz without physical markers. The system fully automates trial initiation and pellet delivery and is capable of accurately delivering stimulation in response to trial outcome with short latency. Kinematic data from the CLARA system provided novel insights into the dynamics of reach consistency over the course of learning, suggesting that learning selectively improves reach failures but does not alter the kinematics of successful reaches. Additionally, using the closed-loop capabilities of CLARA, we demonstrate that vagus nerve stimulation (VNS) improves skilled reach performance and increases reach trajectory consistency in healthy animals.Significance.The CLARA system is the first mouse behavior apparatus that uses markerless pose tracking to provide real-time closed-loop stimulation in response to the outcome of an unconstrained motor task. Additionally, we demonstrate that the CLARA system was essential for our investigating the role of closed-loop VNS stimulation on motor performance in healthy animals. This approach has high translational relevance for developing neurostimulation technology based on complex human behavior.
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Affiliation(s)
- S Bowles
- Neurosurgery, The University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America
- These authors contributed equally
| | - W R Williamson
- NeuroTechnology Center, The University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America
- These authors contributed equally
| | - D Nettles
- Neurosurgery, The University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America
| | - J Hickman
- Neurosurgery, The University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America
| | - C G Welle
- Neurosurgery, The University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States of America
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Bacmeister CM, Barr HJ, McClain CR, Thornton MA, Nettles D, Welle CG, Hughes EG. Motor learning promotes remyelination via new and surviving oligodendrocytes. Nat Neurosci 2020; 23:819-831. [PMID: 32424285 PMCID: PMC7329620 DOI: 10.1038/s41593-020-0637-3] [Citation(s) in RCA: 155] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 04/07/2020] [Indexed: 11/24/2022]
Abstract
Oligodendrocyte loss in neurological disease leaves axons vulnerable to damage and degeneration, and activity-dependent myelination may represent an endogenous mechanism to improve remyelination following injury. Here, we report that while learning a forelimb reach task transiently suppresses oligodendrogenesis, it subsequently increases OPC differentiation, oligodendrocyte generation, and myelin sheath remodeling in the forelimb motor cortex. Immediately followingdemyelination, neurons exhibit hyperexcitability, learning is impaired, and behavioral intervention provides no benefit to remyelination. However, partial remyelination restores neuronal and behavioral function allowing learning to enhance oligodendrogenesis, remyelination of denuded axons, and the ability of surviving oligodendrocytes to generate new myelinsheaths. Previously considered controversial, we show that sheath generation by mature oligodendrocytes is not only possible but also increases myelin pattern preservation following demyelination, presenting a new target for therapeutic interventions. Together, our findings demonstrate that precisely-timed motor learning improves recovery from demyelinating injury via enhanced remyelination from new and surviving oligodendrocytes.
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Affiliation(s)
- Clara M Bacmeister
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Helena J Barr
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Crystal R McClain
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Michael A Thornton
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Dailey Nettles
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA.,Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO, USA.,Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Cristin G Welle
- Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO, USA.,Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ethan G Hughes
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA.
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Welle CG, Gao YR, Ye M, Lozzi A, Boretsky A, Abliz E, Hammer DX. Longitudinal neural and vascular structural dynamics produced by chronic microelectrode implantation. Biomaterials 2020; 238:119831. [PMID: 32045783 DOI: 10.1016/j.biomaterials.2020.119831] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 01/06/2020] [Accepted: 01/25/2020] [Indexed: 12/16/2022]
Abstract
Implanted microelectrode arrays sense local neuronal activity, signals which are used as control commands for brain computer interface (BCI) technology. Patients with tetraplegia have used BCI technology to achieve an extraordinary degree of interaction with their local environment. However, current microelectrode arrays for BCIs lose the ability to record high-quality neural signals in the months-to-years following implantation. Very little is known regarding the dynamic response of neurons and vasculature in the months following electrode array implantation, but loss of structural integrity near the electrode may contribute to the degradation of recording signals. Here, we use in-vivo dual-modality imaging to characterize neuronal and vasculature structures in the same animal for 3 months following electrode insertion. We find ongoing neuronal atrophy, but relative vascular stability, in close proximity to the electrode, along with evidence suggesting links between rare, abrupt hypoxic events and neuronal process atrophy.
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Affiliation(s)
- Cristin G Welle
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA; Departments of Neurosurgery and Physiology & Biophysics, University of Colorado, Anschutz Medical Campus, Aurora, CO, USA.
| | - Yu-Rong Gao
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA; Department of Neuroscience and Multiphoton Imaging Core Facility, University of Rochester Medical Center, Rochester, NY, USA
| | - Meijun Ye
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA
| | - Andrea Lozzi
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA; Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Adam Boretsky
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA; Engility Corporation, San Antonio, TX, USA
| | - Erkinay Abliz
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA
| | - Daniel X Hammer
- Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Radiological Devices, Food and Drug Administration, Silver Spring, MD, USA
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Ereifej ES, Shell CE, Schofield JS, Charkhkar H, Cuberovic I, Dorval AD, Graczyk EL, Kozai TDY, Otto KJ, Tyler DJ, Welle CG, Widge AS, Zariffa J, Moritz CT, Bourbeau DJ, Marasco PD. Neural engineering: the process, applications, and its role in the future of medicine. J Neural Eng 2019; 16:063002. [PMID: 31557730 DOI: 10.1088/1741-2552/ab4869] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE Recent advances in neural engineering have restored mobility to people with paralysis, relieved symptoms of movement disorders, reduced chronic pain, restored the sense of hearing, and provided sensory perception to individuals with sensory deficits. APPROACH This progress was enabled by the team-based, interdisciplinary approaches used by neural engineers. Neural engineers have advanced clinical frontiers by leveraging tools and discoveries in quantitative and biological sciences and through collaborations between engineering, science, and medicine. The movement toward bioelectronic medicines, where neuromodulation aims to supplement or replace pharmaceuticals to treat chronic medical conditions such as high blood pressure, diabetes and psychiatric disorders is a prime example of a new frontier made possible by neural engineering. Although one of the major goals in neural engineering is to develop technology for clinical applications, this technology may also offer unique opportunities to gain insight into how biological systems operate. MAIN RESULTS Despite significant technological progress, a number of ethical and strategic questions remain unexplored. Addressing these questions will accelerate technology development to address unmet needs. The future of these devices extends far beyond treatment of neurological impairments, including potential human augmentation applications. Our task, as neural engineers, is to push technology forward at the intersection of disciplines, while responsibly considering the readiness to transition this technology outside of the laboratory to consumer products. SIGNIFICANCE This article aims to highlight the current state of the neural engineering field, its links with other engineering and science disciplines, and the challenges and opportunities ahead. The goal of this article is to foster new ideas for innovative applications in neurotechnology.
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Affiliation(s)
- Evon S Ereifej
- Veteran Affairs Ann Arbor Healthcare System, Ann Arbor, MI, United States of America. Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America. Department of Neurology, University of Michigan, Ann Arbor, MI, United States of America. Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
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Abstract
As scientists and engineers, we must recognize the overwhelming evidence that we each harbor bias that influences our professional decisions. Yet, solving today's increasingly complex public health challenges requires diverse perspectives from multidisciplinary teams. We all have the opportunity to actively promote a more representative scientific community; let's harness the power of collective action to build diverse teams that deliver the most innovative science.
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Affiliation(s)
- Maria Asplund
- BrainLinks-BrainTools Center, University of Freiburg, Freiburg, Germany; Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.
| | - Cristin G Welle
- Departments of Neurosurgery and Bioengineering, University of Colorado-Anschutz Medical Campus, Aurora, CO, USA.
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Wang J, Lin J, Chen Y, Welle CG, Pfefer TJ. Phantom-based evaluation of near-infrared intracranial hematoma detector performance. J Biomed Opt 2019; 24:1-10. [PMID: 30989838 PMCID: PMC6989771 DOI: 10.1117/1.jbo.24.4.045001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 03/20/2019] [Indexed: 05/29/2023]
Abstract
Near-infrared spectroscopy (NIRS) is emerging as a rapid, low-cost approach for point-of-care triage of hematomas resulting from traumatic brain injury. However, there remains a lack of standardized test methods for benchtop performance assessment of these devices and incomplete understanding of relevant light-tissue interactions. We propose a phantom-based test method for systems operating near the 800-nm oxy-/deoxy-hemoglobin isosbestic point and implement it to evaluate a clinical system. Semi-idealized phantom geometries are designed to represent epidural/subdural, subarachnoid, and intracerebral hemorrhages. Measurements of these phantoms are made with a commercial NIRS-based hematoma detector to quantify the effect of hematoma type, depth, and size, as well as measurement repeatability and detector positioning relative to the hematoma. Results indicated high sensitivity to epidural/subdural and subarachnoid hematomas. Intracerebral hematomas are detectable to a maximum depth of ∼2.5 cm, depending on thickness and diameter. The maximum lateral detection area for the single-emitter/single-collector device studied here appears elliptical and decreases strongly with inclusion depth. Overall, this study provides unique insights into hematoma detector function and indicates the utility of modular polymer tissue phantoms in performance tests for emerging NIRS-based cerebral diagnostic technology.
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Affiliation(s)
- Jianting Wang
- U.S. Food and Drug Administration, Center for Devices and Radiological Health, Silver Spring, Maryland, United States
| | - Jonathan Lin
- U.S. Food and Drug Administration, Center for Devices and Radiological Health, Silver Spring, Maryland, United States
| | - Yu Chen
- University of Maryland, Fischell Department of Bioengineering, College Park, Maryland, United States
| | - Cristin G. Welle
- U.S. Food and Drug Administration, Center for Devices and Radiological Health, Silver Spring, Maryland, United States
- University of Colorado, Department of Neurosurgery and Bioengineering, Aurora, Colorado, United States
| | - T. Joshua Pfefer
- U.S. Food and Drug Administration, Center for Devices and Radiological Health, Silver Spring, Maryland, United States
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Peng X, Hickman JL, Bowles SG, Donegan DC, Welle CG. Innovations in electrical stimulation harness neural plasticity to restore motor function. Bioelectron Med (Lond) 2018; 1:251-263. [PMID: 33859830 DOI: 10.2217/bem-2019-0002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Novel technology and innovative stimulation paradigms allow for unprecedented spatiotemporal precision and closed-loop implementation of neurostimulation systems. In turn, precise, closed-loop neurostimulation appears to preferentially drive neural plasticity in motor networks, promoting neural repair. Recent clinical studies demonstrate that electrical stimulation can drive neural plasticity in damaged motor circuits, leading to meaningful improvement in users. Future advances in these areas hold promise for the treatment of a wide range of motor systems disorders.
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Affiliation(s)
- Xiaoyu Peng
- Dept. of Neurosurgery, University of Colorado, Anschutz Medical Campus, 12700 East 19th Avenue, Aurora, CO 80045
| | - Jordan L Hickman
- Dept. of Neurosurgery, University of Colorado, Anschutz Medical Campus, 12700 East 19th Avenue, Aurora, CO 80045
| | - Spencer G Bowles
- Dept. of Neurosurgery, University of Colorado, Anschutz Medical Campus, 12700 East 19th Avenue, Aurora, CO 80045
| | - Dane C Donegan
- Dept. of Neurosurgery, University of Colorado, Anschutz Medical Campus, 12700 East 19th Avenue, Aurora, CO 80045.,ETH Zurich, Department Health Science and Technology, Institute for Neuroscience. Schorenstrasse 16, 8603 Schwerzenbach, Switzerland
| | - Cristin G Welle
- Dept. of Neurosurgery, University of Colorado, Anschutz Medical Campus, 12700 East 19th Avenue, Aurora, CO 80045
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Street MG, Welle CG, Takmakov PA. Automated reactive accelerated aging for rapid in vitro evaluation of neural implant performance. Rev Sci Instrum 2018; 89:094301. [PMID: 30278703 DOI: 10.1063/1.5024686] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 08/14/2018] [Indexed: 06/08/2023]
Abstract
Novel therapeutic applications for neural implants require miniaturized devices. Miniaturization imposes stricter requirements for reliability of materials. Pilot clinical studies suggest that rapid failure of the miniaturized neural implants in the body presents a major challenge for this type of technology. Traditional evaluations of neural implant performance over clinically relevant durations present time- and resource-intensive experiments in animals. Reactive accelerated aging (RAA) is an in vitro test platform that was developed to expedite durability testing of neural implants, as a screening technique designed to simulate the aggressive physiological environment experienced by the implants. This approach employs hydrogen peroxide, which mimics reactive oxygen species, and a high temperature to accelerate chemical reactions that lead to device degradation similar to that found with devices implanted in vivo. The original RAA system required daily manual maintenance and was prone to variability in performance. To address these limitations, this work introduces automated reactive accelerated aging (aRAA) with closed-loop monitoring components that make the system simple, robust, and scalable. The core novel technology in the aRAA is electrochemical detection for feedback control of hydrogen peroxide concentration, implemented with simple off-the-shelf components. The aRAA can run multiple parallel experiments for high-throughput device testing and optimization. For this reason, the aRAA provides a simple tool for rapid in vitro evaluation of the durability of neural implants, ultimately expediting the development of a new generation of miniaturized devices with a long functional lifespan.
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Affiliation(s)
- Matthew G Street
- Division of Biology, Chemistry, and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, White Oak Federal Research Center, Silver Spring, Maryland 20993, USA
| | - Cristin G Welle
- Departments of Neurosurgery and Bioengineering, Anschutz Medical Center, University of Colorado, Aurora, Colorado 80045, USA
| | - Pavel A Takmakov
- Division of Biology, Chemistry, and Materials Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, White Oak Federal Research Center, Silver Spring, Maryland 20993, USA
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14
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Abstract
Two papers in this issue of Neuron by Saleem et al. (2017) and Storchi et al. (2017) show that increases in background light intensity trigger proportional increases in narrowband gamma oscillations with a peak at 60 Hz in retina, lateral geniculate, and primary visual cortex of the mouse visual system.
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Affiliation(s)
- Cristin G Welle
- Departments of Neurosurgery and Bioengineering, University of Colorado, Denver, CO 80045, USA; Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Diego Contreras
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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15
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Jang H, Huang S, Hammer DX, Wang L, Rafi H, Ye M, Welle CG, Fisher JAN. Alterations in neurovascular coupling following acute traumatic brain injury. Neurophotonics 2017; 4:045007. [PMID: 29296629 PMCID: PMC5741992 DOI: 10.1117/1.nph.4.4.045007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023]
Abstract
Following acute traumatic brain injury (TBI), timely transport to a hospital can significantly improve the prognosis for recovery. There is, however, a dearth of quantitative biomarkers for brain injury that can be rapidly acquired and interpreted in active, field environments in which TBIs are frequently incurred. We explored potential functional indicators for TBI that can be noninvasively obtained through portable detection modalities, namely optical and electrophysiological approaches. By combining diffuse correlation spectroscopy with colocalized electrophysiological measurements in a mouse model of TBI, we observed concomitant alterations in sensory-evoked cerebral blood flow (CBF) and electrical potentials following controlled cortical impact. Injury acutely reduced the peak amplitude of both electrophysiological and CBF responses, which mostly recovered to baseline values within 30 min, and intertrial variability for these parameters was also acutely altered. Notably, the postinjury dynamics of the CBF overshoot and undershoot amplitudes differed significantly; whereas the amplitude of the initial peak of stimulus-evoked CBF recovered relatively rapidly, the ensuing undershoot did not appear to recover within 30 min of injury. Additionally, acute injury induced apparent low-frequency oscillatory behavior in CBF ([Formula: see text]). Histological assessment indicated that these physiological alterations were not associated with any major, persisting anatomical changes. Several time-domain features of the blood flow and electrophysiological responses showed strong correlations in recovery kinetics. Overall, our results reveal an array of stereotyped, injury-induced alterations in electrophysiological and hemodynamic responses that can be rapidly obtained using a combination of portable detection techniques.
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Affiliation(s)
- Hyounguk Jang
- New York Medical College, Department of Physiology, Valhalla, New York, United States
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Stanley Huang
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Daniel X. Hammer
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Lin Wang
- New York Medical College, Department of Physiology, Valhalla, New York, United States
| | - Harmain Rafi
- New York Medical College, Department of Physiology, Valhalla, New York, United States
| | - Meijun Ye
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
| | - Cristin G. Welle
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
- University of Colorado Denver, Departments of Neurosurgery and Bioengineering, Aurora, Colorado, United States
| | - Jonathan A. N. Fisher
- New York Medical College, Department of Physiology, Valhalla, New York, United States
- U.S. Food and Drug Administration, Division of Biomedical Physics, Silver Spring, Maryland, United States
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Huang S, Fisher JAN, Ye M, Kim YS, Ma R, Nabili M, Krauthamer V, Myers MR, Coleman TP, Welle CG. Epidermal Electrode Technology for Detecting Ultrasonic Perturbation of Sensory Brain Activity. IEEE Trans Biomed Eng 2017; 65:1272-1280. [PMID: 28858781 DOI: 10.1109/tbme.2017.2713647] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE We aim to demonstrate the in vivo capability of a wearable sensor technology to detect localized perturbations of sensory-evoked brain activity. METHODS Cortical somatosensory evoked potentials (SSEPs) were recorded in mice via wearable, flexible epidermal electrode arrays. We then utilized the sensors to explore the effects of transcranial focused ultrasound, which noninvasively induced neural perturbation. SSEPs recorded with flexible epidermal sensors were quantified and benchmarked against those recorded with invasive epidural electrodes. RESULTS We found that cortical SSEPs recorded by flexible epidermal sensors were stimulus frequency dependent. Immediately following controlled, focal ultrasound perturbation, the sensors detected significant SSEP modulation, which consisted of dynamic amplitude decreases and altered stimulus-frequency dependence. These modifications were also dependent on the ultrasound perturbation dosage. The effects were consistent with those recorded with invasive electrodes, albeit with roughly one order of magnitude lower signal-to-noise ratio. CONCLUSION We found that flexible epidermal sensors reported multiple SSEP parameters that were sensitive to focused ultrasound. This work therefore 1) establishes that epidermal electrodes are appropriate for monitoring the integrity of major CNS functionalities through SSEP; and 2) leveraged this technology to explore ultrasound-induced neuromodulation. The sensor technology is well suited for this application because the sensor electrical properties are uninfluenced by direct exposure to ultrasound irradiation. SIGNIFICANCE The sensors and experimental paradigm we present involve standard, safe clinical neurological assessment methods and are thus applicable to a wide range of future translational studies in humans with any manner of health condition.
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17
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Hammer DX, Lozzi A, Boretsky A, Welle CG. Acute insertion effects of penetrating cortical microelectrodes imaged with quantitative optical coherence angiography. Neurophotonics 2016; 3:025002. [PMID: 32064297 PMCID: PMC7011942 DOI: 10.1117/1.nph.3.2.025002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 03/16/2016] [Indexed: 05/16/2023]
Abstract
The vascular response during cortical microelectrode insertion was measured with amplitude decorrelation-based quantitative optical coherence angiography (OCA). Four different shank-style microelectrode configurations were inserted in murine motor cortex beneath a surgically implanted window in discrete steps while OCA images were collected and processed for angiography and flowmetry. Quantitative measurements included tissue displacement (measured by optical flow), perfused capillary density, and capillary flow velocity. The primary effect of insertion was mechanical perturbation, the effects of which included tissue displacement, arteriolar rupture, and compression of a branch of the anterior cerebral artery causing a global decrease in flow. Other effects observed included local flow drop-out in the region immediately surrounding the microelectrode. The mean basal capillary network velocity for all animals was 0.23 ( ± 0.05 SD ) and 0.18 ( ± 0.07 SD ) mm / s for capillaries from 100 to 300 μ m and 300 to 500 μ m , respectively. Upon insertion, the 2-shank electrode arrays caused a decrease in capillary flow density and velocity, while the results from other configurations were not different from controls. The proximity to large vessels appears to play a larger role than the array configuration. These results can guide neurosurgeons and electrode designers to minimize trauma and ischemia during microelectrode insertion.
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Affiliation(s)
- Daniel X. Hammer
- Center for Devices and Radiological Health, Food and Drug Administration, Division of Biomedical Physics, Office of Science and Engineering Laboratories, 20903 New Hampshire Avenue, Silver Spring, Maryland 20993, United States
- Address all correspondence to: Daniel X. Hammer, E-mail:
| | - Andrea Lozzi
- Center for Devices and Radiological Health, Food and Drug Administration, Division of Biomedical Physics, Office of Science and Engineering Laboratories, 20903 New Hampshire Avenue, Silver Spring, Maryland 20993, United States
| | - Adam Boretsky
- Center for Devices and Radiological Health, Food and Drug Administration, Division of Biomedical Physics, Office of Science and Engineering Laboratories, 20903 New Hampshire Avenue, Silver Spring, Maryland 20993, United States
| | - Cristin G. Welle
- Center for Devices and Radiological Health, Food and Drug Administration, Division of Biomedical Physics, Office of Science and Engineering Laboratories, 20903 New Hampshire Avenue, Silver Spring, Maryland 20993, United States
- University of Colorado Denver, Departments of Neurosurgery and Bioengineering, 12700 East 19th Avenue, Aurora, Colorado 80045, United States
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18
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Fisher JAN, Huang S, Ye M, Nabili M, Wilent WB, Krauthamer V, Myers MR, Welle CG. Real-Time Detection and Monitoring of Acute Brain Injury Utilizing Evoked Electroencephalographic Potentials. IEEE Trans Neural Syst Rehabil Eng 2016; 24:1003-1012. [PMID: 26955039 DOI: 10.1109/tnsre.2016.2529663] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rapid detection and diagnosis of a traumatic brain injury (TBI) can significantly improve the prognosis for recovery. Helmet-mounted sensors that detect impact severity based on measurements of acceleration or pressure show promise for aiding triage and transport decisions in active, field environments such as professional sports or military combat. The detected signals, however, report on the mechanics of an impact rather than directly indicating the presence and severity of an injury. We explored the use of cortical somatosensory evoked electroencephalographic potentials (SSEPs) to detect and track, in real-time, neural electrophysiological abnormalities within the first hour following head injury in an animal model. To study the immediate electrophysiological effects of injury in vivo, we developed an experimental paradigm involving focused ultrasound that permits continuous, real-time measurements and minimizes mechanical artifact. Injury was associated with a dramatic reduction of amplitude over the damaged hemisphere directly after the injury. The amplitude systematically improved over time but remained significantly decreased at one hour, compared with baseline. In contrast, at one hour there was a concomitant enhancement of the cortical SSEP amplitude evoked from the uninjured hemisphere. Analysis of the inter-trial electroencephalogram (EEG) also revealed significant changes in low-frequency components and an increase in EEG entropy up to 30 minutes after injury, likely reflecting altered EEG reactivity to somatosensory stimuli. Injury-induced alterations in SSEPs were also observed using noninvasive epidermal electrodes, demonstrating viability of practical implementation. These results suggest cortical SSEPs recorded at just a few locations by head-mounted sensors and associated multiparametric analyses could potentially be used to rapidly detect and monitor brain injury in settings that normally present significant levels of mechanical and electrical noise.
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19
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Bowsher K, Civillico EF, Coburn J, Collinger J, Contreras-Vidal JL, Denison T, Donoghue J, French J, Getzoff N, Hochberg LR, Hoffmann M, Judy J, Kleitman N, Knaack G, Krauthamer V, Ludwig K, Moynahan M, Pancrazio JJ, Peckham PH, Pena C, Pinto V, Ryan T, Saha D, Scharen H, Shermer S, Skodacek K, Takmakov P, Tyler D, Vasudevan S, Wachrathit K, Weber D, Welle CG, Ye M. Brain–computer interface devices for patients with paralysis and amputation: a meeting report. J Neural Eng 2016; 13:023001. [DOI: 10.1088/1741-2560/13/2/023001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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20
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Abstract
OBJECTIVE Recent initiatives in bioelectronic modulation of the nervous system by the NIH (SPARC), DARPA (ElectRx, SUBNETS) and the GlaxoSmithKline Bioelectronic Medicines effort are ushering in a new era of therapeutic electrical stimulation. These novel therapies are prompting a re-evaluation of established electrical thresholds for stimulation-induced tissue damage. APPROACH In this review, we explore what is known and unknown in published literature regarding tissue damage from electrical stimulation. MAIN RESULTS For macroelectrodes, the potential for tissue damage is often assessed by comparing the intensity of stimulation, characterized by the charge density and charge per phase of a stimulus pulse, with a damage threshold identified through histological evidence from in vivo experiments as described by the Shannon equation. While the Shannon equation has proved useful in assessing the likely occurrence of tissue damage, the analysis is limited by the experimental parameters of the original studies. Tissue damage is influenced by factors not explicitly incorporated into the Shannon equation, including pulse frequency, duty cycle, current density, and electrode size. Microelectrodes in particular do not follow the charge per phase and charge density co-dependence reflected in the Shannon equation. The relevance of these factors to tissue damage is framed in the context of available reports from modeling and in vivo studies. SIGNIFICANCE It is apparent that emerging applications, especially with microelectrodes, will require clinical charge densities that exceed traditional damage thresholds. Experimental data show that stimulation at higher charge densities can be achieved without causing tissue damage, suggesting that safety parameters for microelectrodes might be distinct from those defined for macroelectrodes. However, these increased charge densities may need to be justified by bench, non-clinical or clinical testing to provide evidence of device safety.
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Affiliation(s)
- Stuart F Cogan
- The Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
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21
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Welle CG, Contreras D. Sensory-driven and spontaneous gamma oscillations engage distinct cortical circuitry. J Neurophysiol 2015; 115:1821-35. [PMID: 26719085 DOI: 10.1152/jn.00137.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 12/29/2015] [Indexed: 11/22/2022] Open
Abstract
Gamma oscillations are a robust component of sensory responses but are also part of the background spontaneous activity of the brain. To determine whether the properties of gamma oscillations in cortex are specific to their mechanism of generation, we compared in mouse visual cortex in vivo the laminar geometry and single-neuron rhythmicity of oscillations produced during sensory representation with those occurring spontaneously in the absence of stimulation. In mouse visual cortex under anesthesia (isoflurane and xylazine), visual stimulation triggered oscillations mainly between 20 and 50 Hz, which, because of their similar functional significance to gamma oscillations in higher mammals, we define here as gamma range. Sensory representation in visual cortex specifically increased gamma oscillation amplitude in the supragranular (L2/3) and granular (L4) layers and strongly entrained putative excitatory and inhibitory neurons in infragranular layers, while spontaneous gamma oscillations were distributed evenly through the cortical depth and primarily entrained putative inhibitory neurons in the infragranular (L5/6) cortical layers. The difference in laminar distribution of gamma oscillations during the two different conditions may result from differences in the source of excitatory input to the cortex. In addition, modulation of superficial gamma oscillation amplitude did not result in a corresponding change in deep-layer oscillations, suggesting that superficial and deep layers of cortex may utilize independent but related networks for gamma generation. These results demonstrate that stimulus-driven gamma oscillations engage cortical circuitry in a manner distinct from spontaneous oscillations and suggest multiple networks for the generation of gamma oscillations in cortex.
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Affiliation(s)
- Cristin G Welle
- Division of Biomedical Physics, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, Maryland; and Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Diego Contreras
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
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22
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Lozzi A, Agrawal A, Boretsky A, Welle CG, Hammer DX. Image quality metrics for optical coherence angiography. Biomed Opt Express 2015; 6:2435-2447. [PMID: 26203372 PMCID: PMC4505700 DOI: 10.1364/boe.6.002435] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/13/2015] [Accepted: 06/09/2015] [Indexed: 05/20/2023]
Abstract
We characterized image quality in optical coherence angiography (OCA) en face planes of mouse cortical capillary network in terms of signal-to-noise ratio (SNR) and Weber contrast (Wc) through a novel mask-based segmentation method. The method was used to compare two adjacent B-scan processing algorithms, (1) average absolute difference (AAD) and (2) standard deviation (SD), while varying the number of lateral cross-sections acquired (also known as the gate length, N). AAD and SD are identical at N = 2 and exhibited similar image quality for N<10. However, AAD is relatively less susceptible to bulk tissue motion artifact than SD. SNR and Wc were 15% and 35% higher for AAD from N = 25 to 100. In addition data sets were acquired with two objective lenses with different magnifications to quantify the effect of lateral resolution on fine capillary detection. The lower power objective yielded a significant mean broadening of 17% in Full Width Half Maximum (FWHM) diameter. These results may guide study and device designs for OCA capillary and blood flow quantification.
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Affiliation(s)
- Andrea Lozzi
- Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring MD 20993, USA
| | - Anant Agrawal
- Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring MD 20993, USA
| | - Adam Boretsky
- Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring MD 20993, USA
| | - Cristin G. Welle
- Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring MD 20993, USA
| | - Daniel X. Hammer
- Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring MD 20993, USA
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23
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Takmakov P, Ruda K, Scott Phillips K, Isayeva IS, Krauthamer V, Welle CG. Rapid evaluation of the durability of cortical neural implants using accelerated aging with reactive oxygen species. J Neural Eng 2015; 12:026003. [PMID: 25627426 DOI: 10.1088/1741-2560/12/2/026003] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE A challenge for implementing high bandwidth cortical brain-machine interface devices in patients is the limited functional lifespan of implanted recording electrodes. Development of implant technology currently requires extensive non-clinical testing to demonstrate device performance. However, testing the durability of the implants in vivo is time-consuming and expensive. Validated in vitro methodologies may reduce the need for extensive testing in animal models. APPROACH Here we describe an in vitro platform for rapid evaluation of implant stability. We designed a reactive accelerated aging (RAA) protocol that employs elevated temperature and reactive oxygen species (ROS) to create a harsh aging environment. Commercially available microelectrode arrays (MEAs) were placed in a solution of hydrogen peroxide at 87 °C for a period of 7 days. We monitored changes to the implants with scanning electron microscopy and broad spectrum electrochemical impedance spectroscopy (1 Hz-1 MHz) and correlated the physical changes with impedance data to identify markers associated with implant failure. MAIN RESULTS RAA produced a diverse range of effects on the structural integrity and electrochemical properties of electrodes. Temperature and ROS appeared to have different effects on structural elements, with increased temperature causing insulation loss from the electrode microwires, and ROS concentration correlating with tungsten metal dissolution. All array types experienced impedance declines, consistent with published literature showing chronic (>30 days) declines in array impedance in vivo. Impedance change was greatest at frequencies <10 Hz, and smallest at frequencies 1 kHz and above. Though electrode performance is traditionally characterized by impedance at 1 kHz, our results indicate that an impedance change at 1 kHz is not a reliable predictive marker of implant degradation or failure. SIGNIFICANCE ROS, which are known to be present in vivo, can create structural damage and change electrical properties of MEAs. Broad-spectrum electrical impedance spectroscopy demonstrates increased sensitivity to electrode damage compared with single-frequency measurements. RAA can be a useful tool to simulate worst-case in vivo damage resulting from chronic electrode implantation, simplifying the device development lifecycle.
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Affiliation(s)
- Pavel Takmakov
- Division of Biology, Chemistry and Material Science, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, US Food and Drug Administration, White Oak Federal Research Center, Silver Spring, MD, USA
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24
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Hammer DX, Lozzi A, Abliz E, Greenbaum N, Agrawal A, Krauthamer V, Welle CG. Longitudinal vascular dynamics following cranial window and electrode implantation measured with speckle variance optical coherence angiography. Biomed Opt Express 2014; 5:2823-36. [PMID: 25136505 PMCID: PMC4133009 DOI: 10.1364/boe.5.002823] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 07/14/2014] [Accepted: 07/18/2014] [Indexed: 05/18/2023]
Abstract
Speckle variance optical coherence angiography (OCA) was used to characterize the vascular tissue response from craniotomy, window implantation, and electrode insertion in mouse motor cortex. We observed initial vasodilation ~40% greater than original diameter 2-3 days post-surgery (dps). After 4 weeks, dilation subsided in large vessels (>50 µm diameter) but persisted in smaller vessels (25-50 µm diameter). Neovascularization began 8-12 dps and vessel migration continued throughout the study. Vasodilation and neovascularization were primarily associated with craniotomy and window implantation rather than electrode insertion. Initial evidence of capillary re-mapping in the region surrounding the implanted electrode was manifest in OCA image dissimilarity. Further investigation, including higher resolution imaging, is required to validate the finding. Spontaneous lesions also occurred in many electrode animals, though the inception point appeared random and not directly associated with electrode insertion. OCA allows high resolution, label-free in vivo visualization of neurovascular tissue, which may help determine any biological contribution to chronic electrode signal degradation. Vascular and flow-based biomarkers can aid development of novel neural prostheses.
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25
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Fisher JAN, Barchi JR, Welle CG, Kim GH, Kosterin P, Obaid AL, Yodh AG, Contreras D, Salzberg BM. Two-photon excitation of potentiometric probes enables optical recording of action potentials from mammalian nerve terminals in situ. J Neurophysiol 2008; 99:1545-53. [PMID: 18171710 DOI: 10.1152/jn.00929.2007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We report the first optical recordings of action potentials, in single trials, from one or a few (approximately 1-2 microm) mammalian nerve terminals in an intact in vitro preparation, the mouse neurohypophysis. The measurements used two-photon excitation along the "blue" edge of the two-photon absorption spectrum of di-3-ANEPPDHQ (a fluorescent voltage-sensitive naphthyl styryl-pyridinium dye), and epifluorescence detection, a configuration that is critical for noninvasive recording of electrical activity from intact brains. Single-trial recordings of action potentials exhibited signal-to-noise ratios of approximately 5:1 and fractional fluorescence changes of up to approximately 10%. This method, by virtue of its optical sectioning capability, deep tissue penetration, and efficient epifluorescence detection, offers clear advantages over linear, as well as other nonlinear optical techniques used to monitor voltage changes in localized neuronal regions, and provides an alternative to invasive electrode arrays for studying neuronal systems in vivo.
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Affiliation(s)
- Jonathan A N Fisher
- Department of Neuroscience, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6074, USA
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