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Madarász M, Fedor FZ, Fekete Z, Rózsa B. Immunohistological responses in mice implanted with Parylene HT - ITO ECoG devices. Front Neurosci 2023; 17:1209913. [PMID: 37746144 PMCID: PMC10513038 DOI: 10.3389/fnins.2023.1209913] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 08/17/2023] [Indexed: 09/26/2023] Open
Abstract
Transparent epidural devices that facilitate the concurrent use of electrophysiology and neuroimaging are arising tools for neuroscience. Testing the biocompatibility and evoked immune response of novel implantable devices is essential to lay down the fundamentals of their extensive application. Here we present an immunohistochemical evaluation of a Parylene HT/indium-tin oxide (ITO) based electrocorticography (ECoG) device, and provide long-term biocompatibility data at three chronic implantation lengths. We implanted Parylene HT/ITO ECoG devices epidurally in 5 mice and evaluated the evoked astroglial response, neuronal density and cortical thickness. We found increased astroglial response in the superficial cortical layers of all mice compared to contralateral unimplanted controls. This difference was largest at the first time point and decreased over time. Neuronal density was lower on the implanted side only at the last time point, while cortical thickness was smaller in the first and second time points, but not at the last. In this study, we present data that confirms the feasibility and chronic use of Parylene HT/ITO ECoG devices.
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Affiliation(s)
- Miklós Madarász
- BrainVision Center, Budapest, Hungary
- János Szentágothai PhD Program of Semmelweis University, Budapest, Hungary
| | - Flóra Z. Fedor
- BrainVision Center, Budapest, Hungary
- Laboratory of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, Budapest, Hungary
| | - Zoltán Fekete
- Research Group for Implantable Microsystems, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
- Sleep Oscillation Research Group, Institute of Cognitive Neuroscience and Psychology, Research Center for Natural Sciences, Budapest, Hungary
| | - Balázs Rózsa
- BrainVision Center, Budapest, Hungary
- Laboratory of 3D Functional Network and Dendritic Imaging, Institute of Experimental Medicine, Budapest, Hungary
- Two-Photon Measurement Technology Research Group, The Faculty of Information Technology, Pázmány Péter Catholic University, Budapest, Hungary
- Femtonics Ltd., Budapest, Hungary
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Csernyus B, Szabó Á, Fiáth R, Zátonyi A, Lázár C, Pongrácz A, Fekete Z. A multimodal, implantable sensor array and measurement system to investigate the suppression of focal epileptic seizure using hypothermia. J Neural Eng 2021; 18. [PMID: 34280911 DOI: 10.1088/1741-2552/ac15e6] [Citation(s) in RCA: 2] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/19/2021] [Indexed: 11/12/2022]
Abstract
Objective.Local cooling of the brain as a therapeutic intervention is a promising alternative for patients with epilepsy who do not respond to medication.In vitroandin vivostudies have demonstrated the seizure-suppressing effect of local cooling in various animal models. In our work, focal brain cooling in a bicuculline induced epilepsy model in rats is demonstrated and evaluated using a multimodal micro-electrocorticography (microECoG) device.Approach.We designed and experimentally tested a novel polyimide-based sensor array capable of recording microECoG and temperature signals concurrently from the cortical surface of rats. The effect of cortical cooling after seizure onset was evaluated using 32 electrophysiological sites and eight temperature sensing elements covering the brain hemisphere, where injection of the epileptic drug was performed. The focal cooling of the cortex right above the injection site was accomplished using a miniaturized Peltier chip combined with a heat pipe to transfer heat. Control of cooling and collection of sensor data was provided by a custom designed Arduino based electronic board. We tested the experimental setup using an agar gel modelin vitro, and thenin vivoin Wistar rats.Main results.Spatial variation of temperature during the Peltier controlled cooling was evaluated through calibrated, on-chip platinum temperature sensors. We found that frequency of epileptic discharges was not substantially reduced by cooling the cortical surface to 30 °C, but was suppressed efficiently at temperature values around 20 °C. The multimodal array revealed that seizure-like ictal events far from the focus and not exposed to high drop in temperature can be also inhibited at an extent like the directly cooled area.Significance.Our results imply that not only the absolute drop in temperature determines the efficacy of seizure suppression, and distant cortical areas not directly cooled can be influenced.
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Affiliation(s)
- B Csernyus
- Research Group for Implantable Microsystems, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Á Szabó
- Research Group for Implantable Microsystems, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary.,Roska Tamás Interdisciplinary Doctoral School, Pázmány Péter Catholic University, Budapest, Hungary
| | - R Fiáth
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - A Zátonyi
- Research Group for Implantable Microsystems, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - C Lázár
- Microsystems Laboratory, Institute of Technical Physics and Material Sciences, Center for Energy Research, Budapest, Hungary
| | - A Pongrácz
- Research Group for Implantable Microsystems, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Z Fekete
- Research Group for Implantable Microsystems, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
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Hermiz J, Rogers N, Kaestner E, Ganji M, Cleary DR, Carter BS, Barba D, Dayeh SA, Halgren E, Gilja V. Sub-millimeter ECoG pitch in human enables higher fidelity cognitive neural state estimation. Neuroimage 2018; 176:454-464. [PMID: 29678760 DOI: 10.1016/j.neuroimage.2018.04.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [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: 11/02/2017] [Revised: 03/09/2018] [Accepted: 04/11/2018] [Indexed: 10/17/2022] Open
Abstract
Electrocorticography (ECoG), electrophysiological recording from the pial surface of the brain, is a critical measurement technique for clinical neurophysiology, basic neurophysiology studies, and demonstrates great promise for the development of neural prosthetic devices for assistive applications and the treatment of neurological disorders. Recent advances in device engineering are poised to enable orders of magnitude increase in the resolution of ECoG without comprised measurement quality. This enhancement in cortical sensing enables the observation of neural dynamics from the cortical surface at the micrometer scale. While these technical capabilities may be enabling, the extent to which finer spatial scale recording enhances functionally relevant neural state inference is unclear. We examine this question by employing a high-density and low impedance 400 μm pitch microECoG (μECoG) grid to record neural activity from the human cortical surface during cognitive tasks. By applying machine learning techniques to classify task conditions from the envelope of high-frequency band (70-170Hz) neural activity collected from two study participants, we demonstrate that higher density grids can lead to more accurate binary task condition classification. When controlling for grid area and selecting task informative sub-regions of the complete grid, we observed a consistent increase in mean classification accuracy with higher grid density; in particular, 400 μm pitch grids outperforming spatially sub-sampled lower density grids up to 23%. We also introduce a modeling framework to provide intuition for how spatial properties of measurements affect the performance gap between high and low density grids. To our knowledge, this work is the first quantitative demonstration of human sub-millimeter pitch cortical surface recording yielding higher-fidelity state estimation relative to devices at the millimeter-scale, motivating the development and testing of μECoG for basic and clinical neurophysiology as well as towards the realization of high-performance neural prostheses.
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Affiliation(s)
- John Hermiz
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Nicholas Rogers
- Department of Physics, University of California San Diego, La Jolla, CA, 92161, USA
| | - Erik Kaestner
- Neurosciences Program, University of California San Diego, La Jolla, CA, 92096, USA
| | - Mehran Ganji
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Daniel R Cleary
- Department of Neurosurgery, University of California San Diego, La Jolla, CA, 92103, USA
| | - Bob S Carter
- Department of Neurosurgery, University of California San Diego, La Jolla, CA, 92103, USA
| | - David Barba
- Department of Neurosurgery, University of California San Diego, La Jolla, CA, 92103, USA
| | - Shadi A Dayeh
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, 92093, USA; Department of Materials Science and Engineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Eric Halgren
- Department of Radiology, University of California San Diego, La Jolla, CA, 92103, USA; Department of Neurosciences, University of California San Diego, La Jolla, CA, 92103, USA
| | - Vikash Gilja
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92093, USA.
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