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Shin Y, Ryu J, Bai T, Qiang Y, Qi Y, Li G, Huang Y, Seo KJ, Fang H. Array-wide uniform PEDOT:PSS electroplating from potentiostatic deposition. Biosens Bioelectron 2024; 261:116418. [PMID: 38875864 PMCID: PMC11214878 DOI: 10.1016/j.bios.2024.116418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/04/2024] [Accepted: 05/20/2024] [Indexed: 06/16/2024]
Abstract
Electroplating of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is important in many neuroelectronic applications but is challenging to achieve uniformity on large-scale microelectrode arrays (MEA) using conventional galvanostatic methods. In this study, we address this challenge through a potentiostatic method and demonstrate highly uniform electroplating of PEDOT:PSS on MEA with more than one hundred electrodes, all at cellular sizes. The validation of this approach involves comparisons with galvanostatic deposition methods, showcasing unparalleled deposition yield and uniformity. Systematic electrochemical characterizations reveal similarities in structure and stability from potentiostatic deposited coatings. The advances developed here establish the potentiostatic method and detailed process to achieve a uniform coating of PEDOT:PSS on large-scale MEA, with broad utility in neuroelectronics.
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Affiliation(s)
- Yieljae Shin
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Jaehyeon Ryu
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Tianyu Bai
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Yi Qiang
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Yongli Qi
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Gen Li
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Yunxiang Huang
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA
| | - Kyung Jin Seo
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.
| | - Hui Fang
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, USA.
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Abu Shihada J, Jung M, Decke S, Koschinski L, Musall S, Rincón Montes V, Offenhäusser A. Highly Customizable 3D Microelectrode Arrays for In Vitro and In Vivo Neuronal Tissue Recordings. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305944. [PMID: 38240370 PMCID: PMC10987114 DOI: 10.1002/advs.202305944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 12/05/2023] [Indexed: 02/16/2024]
Abstract
Planar microelectrode arrays (MEAs) for - in vitro or in vivo - neuronal signal recordings lack the spatial resolution and sufficient signal-to-noise ratio (SNR) required for a detailed understanding of neural network function and synaptic plasticity. To overcome these limitations, a highly customizable three-dimensional (3D) printing process is used in combination with thin film technology and a self-aligned template-assisted electrochemical deposition process to fabricate 3D-printed-based MEAs on stiff or flexible substrates. Devices with design flexibility and physical robustness are shown for recording neural activity in different in vitro and in vivo applications, achieving high-aspect ratio 3D microelectrodes of up to 33:1. Here, MEAs successfully record neural activity in 3D neuronal cultures, retinal explants, and the cortex of living mice, thereby demonstrating the versatility of the 3D MEA while maintaining high-quality neural recordings. Customizable 3D MEAs provide unique opportunities to study neural activity under regular or various pathological conditions, both in vitro and in vivo, and contribute to the development of drug screening and neuromodulation systems that can accurately monitor the activity of large neural networks over time.
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Affiliation(s)
- J. Abu Shihada
- Institute of Biological Information Processing (IBI‐3) – BioelectronicsForschungszentrum52428JülichGermany
- RWTH Aachen University52062AachenGermany
| | - M. Jung
- Institute of Biological Information Processing (IBI‐3) – BioelectronicsForschungszentrum52428JülichGermany
- RWTH Aachen University52062AachenGermany
| | - S. Decke
- Institute of Biological Information Processing (IBI‐3) – BioelectronicsForschungszentrum52428JülichGermany
| | - L. Koschinski
- Institute of Biological Information Processing (IBI‐3) – BioelectronicsForschungszentrum52428JülichGermany
- RWTH Aachen University52062AachenGermany
- Helmholtz Nano Facility (HNF)Forschungszentrum Jülich52428JülichGermany
| | - S. Musall
- Institute of Biological Information Processing (IBI‐3) – BioelectronicsForschungszentrum52428JülichGermany
- RWTH Aachen University52062AachenGermany
- Faculty of MedicineInstitute of Experimental Epileptology and Cognition ResearchUniversity of Bonn53127BonnGermany
- University Hospital Bonn53127BonnGermany
| | - V. Rincón Montes
- Institute of Biological Information Processing (IBI‐3) – BioelectronicsForschungszentrum52428JülichGermany
| | - A. Offenhäusser
- Institute of Biological Information Processing (IBI‐3) – BioelectronicsForschungszentrum52428JülichGermany
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Abdulbaki A, Doll T, Helgers S, Heissler HE, Voges J, Krauss JK, Schwabe K, Alam M. Subthalamic Nucleus Deep Brain Stimulation Restores Motor and Sensorimotor Cortical Neuronal Oscillatory Activity in the Free-Moving 6-Hydroxydopamine Lesion Rat Parkinson Model. Neuromodulation 2024; 27:489-499. [PMID: 37002052 DOI: 10.1016/j.neurom.2023.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 12/28/2022] [Accepted: 01/04/2023] [Indexed: 03/31/2023]
Abstract
OBJECTIVES Enhanced beta oscillations in cortical-basal ganglia (BG) thalamic circuitries have been linked to clinical symptoms of Parkinson's disease. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) reduces beta band activity in BG regions, whereas little is known about activity in cortical regions. In this study, we investigated the effect of STN DBS on the spectral power of oscillatory activity in the motor cortex (MCtx) and sensorimotor cortex (SMCtx) by recording via an electrocorticogram (ECoG) array in free-moving 6-hydroxydopamine (6-OHDA) lesioned rats and sham-lesioned controls. MATERIALS AND METHODS Male Sprague-Dawley rats (250-350 g) were injected either with 6-OHDA or with saline in the right medial forebrain bundle, under general anesthesia. A stimulation electrode was then implanted in the ipsilateral STN, and an ECoG array was placed subdurally above the MCtx and SMCtx areas. Six days after the second surgery, the free-moving rats were individually recorded in three conditions: 1) basal activity, 2) during STN DBS, and 3) directly after STN DBS. RESULTS In 6-OHDA-lesioned rats (N = 8), the relative power of theta band activity was reduced, whereas activity of broad-range beta band (12-30 Hz) along with two different subbeta bands, that is, low (12-30 Hz) and high (20-30 Hz) beta band and gamma band, was higher in MCtx and SMCtx than in sham-lesioned controls (N = 7). This was, to some extent, reverted toward control level by STN DBS during and after stimulation. No major differences were found between contacts of the electrode grid or between MCtx and SMCtx. CONCLUSION Loss of nigrostriatal dopamine leads to abnormal oscillatory activity in both MCtx and SMCtx, which is compensated by STN stimulation, suggesting that parkinsonism-related oscillations in the cortex and BG are linked through their anatomic connections.
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Affiliation(s)
- Arif Abdulbaki
- Hannover Medical School, Department of Neurosurgery, Hannover, Germany.
| | - Theodor Doll
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany
| | - Simeon Helgers
- Hannover Medical School, Department of Neurosurgery, Hannover, Germany
| | - Hans E Heissler
- Hannover Medical School, Department of Neurosurgery, Hannover, Germany
| | - Jürgen Voges
- Department of Stereotactic Neurosurgery, University Hospital Magdeburg, Magdeburg, Germany
| | - Joachim K Krauss
- Hannover Medical School, Department of Neurosurgery, Hannover, Germany
| | - Kerstin Schwabe
- Hannover Medical School, Department of Neurosurgery, Hannover, Germany
| | - Mesbah Alam
- Hannover Medical School, Department of Neurosurgery, Hannover, Germany
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Koschinski L, Lenyk B, Jung M, Lenzi I, Kampa B, Mayer D, Offenhäusser A, Musall S, Rincón Montes V. Validation of transparent and flexible neural implants for simultaneous electrophysiology, functional imaging, and optogenetics. J Mater Chem B 2023; 11:9639-9657. [PMID: 37610228 DOI: 10.1039/d3tb01191g] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The combination of electrophysiology and neuroimaging methods allows the simultaneous measurement of electrical activity signals with calcium dynamics from single neurons to neuronal networks across distinct brain regions in vivo. While traditional electrophysiological techniques are limited by photo-induced artefacts and optical occlusion for neuroimaging, different types of transparent neural implants have been proposed to resolve these issues. However, reproducing proposed solutions is often challenging and it remains unclear which approach offers the best properties for long-term chronic multimodal recordings. We therefore created a streamlined fabrication process to produce, and directly compare, two types of transparent surface micro-electrocorticography (μECoG) implants: nano-mesh gold structures (m-μECoGs) versus a combination of solid gold interconnects and PEDOT:PSS-based electrodes (pp-μECoGs). Both implants allowed simultaneous multimodal recordings but pp-μECoGs offered the best overall electrical, electrochemical, and optical properties with negligible photo-induced artefacts to light wavelengths of interest. Showing functional chronic stability for up to four months, pp-μECoGs also allowed the simultaneous functional mapping of electrical and calcium neural signals upon visual and tactile stimuli during widefield imaging. Moreover, recordings during two-photon imaging showed no visible signal attenuation and enabled the correlation of network dynamics across brain regions to individual neurons located directly below the transparent electrical contacts.
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Affiliation(s)
- Lina Koschinski
- Institute of Biological Information Processing (IBI-3) - Bioelectronics, Forschungszentrum, Jülich, Germany.
- Helmholtz Nano Facility (HNF), Forschungszentrum, Jülich, Germany
- RWTH Aachen University, Germany
| | - Bohdan Lenyk
- Institute of Biological Information Processing (IBI-3) - Bioelectronics, Forschungszentrum, Jülich, Germany.
| | - Marie Jung
- Institute of Biological Information Processing (IBI-3) - Bioelectronics, Forschungszentrum, Jülich, Germany.
- RWTH Aachen University, Germany
| | - Irene Lenzi
- Institute of Biological Information Processing (IBI-3) - Bioelectronics, Forschungszentrum, Jülich, Germany.
- RWTH Aachen University, Germany
| | - Björn Kampa
- RWTH Aachen University, Germany
- JARA BRAIN Institute of Neuroscience and Medicine (INM-10), Forschungszentrum, Jülich, Germany
| | - Dirk Mayer
- Institute of Biological Information Processing (IBI-3) - Bioelectronics, Forschungszentrum, Jülich, Germany.
| | - Andreas Offenhäusser
- Institute of Biological Information Processing (IBI-3) - Bioelectronics, Forschungszentrum, Jülich, Germany.
| | - Simon Musall
- Institute of Biological Information Processing (IBI-3) - Bioelectronics, Forschungszentrum, Jülich, Germany.
- RWTH Aachen University, Germany
- University of Bonn, Faculty of Medicine, Institute of Experimental Epileptology and Cognition Research, Germany
- University Hospital Bonn, Germany
| | - Viviana Rincón Montes
- Institute of Biological Information Processing (IBI-3) - Bioelectronics, Forschungszentrum, Jülich, Germany.
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Setogawa S, Kanda R, Tada S, Hikima T, Saitoh Y, Ishikawa M, Nakada S, Seki F, Hikishima K, Matsumoto H, Mizuseki K, Fukayama O, Osanai M, Sekiguchi H, Ohkawa N. A novel micro-ECoG recording method for recording multisensory neural activity from the parietal to temporal cortices in mice. Mol Brain 2023; 16:38. [PMID: 37138338 PMCID: PMC10157930 DOI: 10.1186/s13041-023-01019-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 03/09/2023] [Indexed: 05/05/2023] Open
Abstract
Characterization of inter-regional interactions in brain is essential for understanding the mechanism relevant to normal brain function and neurological disease. The recently developed flexible micro (μ)-electrocorticography (μECoG) device is one prominent method used to examine large-scale cortical activity across multiple regions. The sheet-shaped μECoG electrodes arrays can be placed on a relatively wide area of cortical surface beneath the skull by inserting the device into the space between skull and brain. Although rats and mice are useful tools for neuroscience, current μECoG recording methods in these animals are limited to the parietal region of cerebral cortex. Recording cortical activity from the temporal region of cortex in mice has proven difficult because of surgical barriers created by the skull and surrounding temporalis muscle anatomy. Here, we developed a sheet-shaped 64-channel μECoG device that allows access to the mouse temporal cortex, and we determined the factor determining the appropriate bending stiffness for the μECoG electrode array. We also established a surgical technique to implant the electrode arrays into the epidural space over a wide area of cerebral cortex covering from the barrel field to olfactory (piriform) cortex, which is the deepest region of the cerebral cortex. Using histology and computed tomography (CT) images, we confirmed that the tip of the μECoG device reached to the most ventral part of cerebral cortex without causing noticeable damage to the brain surface. Moreover, the device simultaneously recorded somatosensory and odor stimulus-evoked neural activity from dorsal and ventral parts of cerebral cortex in awake and anesthetized mice. These data indicate that our μECoG device and surgical techniques enable the recording of large-scale cortical activity from the parietal to temporal cortex in mice, including somatosensory and olfactory cortices. This system will provide more opportunities for the investigation of physiological functions from wider areas of the mouse cerebral cortex than those currently available with existing ECoG techniques.
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Affiliation(s)
- Susumu Setogawa
- Division for Memory and Cognitive Function, Research Center for Advanced Medical Science, Comprehensive Research Facilities for Advanced Medical Science, Dokkyo Medical University, Tochigi, 321-0293, Japan
- Department of Physiology, Osaka Metropolitan University Graduate School of Medicine, Osaka, 545-8585, Japan
| | - Ryota Kanda
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan
| | - Shuto Tada
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan
| | - Takuya Hikima
- Division for Memory and Cognitive Function, Research Center for Advanced Medical Science, Comprehensive Research Facilities for Advanced Medical Science, Dokkyo Medical University, Tochigi, 321-0293, Japan
| | - Yoshito Saitoh
- Division for Memory and Cognitive Function, Research Center for Advanced Medical Science, Comprehensive Research Facilities for Advanced Medical Science, Dokkyo Medical University, Tochigi, 321-0293, Japan
| | - Mikiko Ishikawa
- Division for Memory and Cognitive Function, Research Center for Advanced Medical Science, Comprehensive Research Facilities for Advanced Medical Science, Dokkyo Medical University, Tochigi, 321-0293, Japan
| | - Satoshi Nakada
- Japanese Center for Research on Women in Sport, Graduate School of Health and Sports Science, Juntendo University, Chiba, 270-1695, Japan
| | - Fumiko Seki
- Live Animal Imaging Center, Central Institutes for Experimental Animals (CIEA), Kanagawa, 210-0821, Japan
| | - Keigo Hikishima
- Medical Devices Research Group, Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8564, Japan
| | - Hideyuki Matsumoto
- Department of Physiology, Osaka Metropolitan University Graduate School of Medicine, Osaka, 545-8585, Japan
| | - Kenji Mizuseki
- Department of Physiology, Osaka Metropolitan University Graduate School of Medicine, Osaka, 545-8585, Japan
| | - Osamu Fukayama
- Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Osaka, 565-0871, Japan
| | - Makoto Osanai
- Laboratory for Physiological Functional Imaging, Department of Medical Physics and Engineering, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan
| | - Hiroto Sekiguchi
- Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi, 441-8580, Japan.
- Japan Science and Technology, Precursory Research for Embryonic Science and Technology (PRESTO), Kawaguchi, Saitama, 332-0012, Japan.
| | - Noriaki Ohkawa
- Division for Memory and Cognitive Function, Research Center for Advanced Medical Science, Comprehensive Research Facilities for Advanced Medical Science, Dokkyo Medical University, Tochigi, 321-0293, Japan.
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Yang S, Xu K, Guan S, Zou L, Gao L, Wang J, Tian H, Li H, Fang Y, Li H. Polymer nanofiber network reinforced gold electrode array for neural activity recording. Biomed Eng Lett 2023; 13:111-118. [PMID: 37124105 PMCID: PMC10130319 DOI: 10.1007/s13534-022-00257-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 11/19/2022] [Accepted: 12/20/2022] [Indexed: 01/04/2023] Open
Abstract
Flexible and stretchable neural electrodes are promising tools for high-fidelity interfacing with soft and curvilinear brain surface. Here, we describe a flexible and stretchable neural electrode array that consists of polyacrylonitrile (PAN) nanofiber network reinforced gold (Au) film electrodes. Under stretching, the interweaving PAN nanofibers effectively terminate the formation of propagating cracks in the Au films and thus enable the formation of a dynamically stable electrode-tissue interface. Moreover, the PAN nanofibers increase the surface roughness and active surface areas of the Au electrodes, leading to reduced electrochemical impedance and improved signal-to-noise ratio. As a result, PAN nanofiber network reinforced Au electrode arrays can allow for reliable in vivo multichannel recording of epileptiform activities in rats. Supplementary Information The online version contains supplementary material available at 10.1007/s13534-022-00257-5.
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Affiliation(s)
- Siting Yang
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Ke Xu
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Shouliang Guan
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
| | - Liang Zou
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Lei Gao
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Jinfen Wang
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
| | - Huihui Tian
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
| | - Hui Li
- School of Physics and Microelectronics, Zhengzhou University, Zhengzhou, 450052 China
| | - Ying Fang
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
- CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Hongbian Li
- CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190 China
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Uguz I, Shepard KL. Spatially controlled, bipolar, cortical stimulation with high-capacitance, mechanically flexible subdural surface microelectrode arrays. SCIENCE ADVANCES 2022; 8:eabq6354. [PMID: 36260686 PMCID: PMC9581492 DOI: 10.1126/sciadv.abq6354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 09/07/2022] [Indexed: 06/16/2023]
Abstract
Most neuromodulation approaches rely on extracellular electrical stimulation with penetrating electrodes at the cost of cortical damage. Surface electrodes, in contrast, are much less invasive but are challenged by the lack of proximity to axonal processes, leading to poor resolution. Here, we demonstrate that high-density (40-μm pitch), high-capacitance (>1 nF), single neuronal resolution PEDOT:PSS electrodes can be programmed to shape the charge injection front selectively at depths approaching 300 micrometers with a lateral resolution better than 100 micrometers. These electrodes, patterned on thin-film parylene substrate, can be subdurally implanted and adhere to the pial surface in chronic settings. By leveraging surface arrays that are optically transparent with PEDOT:PSS local interconnects and integrated with depth electrodes, we are able to combine surface stimulation and recording with calcium imaging and depth recording to demonstrate these spatial limits of bidirectional communication with pyramidal neurons in mouse visual cortex both laterally and at depth from the surface.
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8
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A flexible implantable microelectrode array for recording electrocorticography signals from rodents. Biomed Microdevices 2022; 24:31. [PMID: 36138255 DOI: 10.1007/s10544-022-00632-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2022] [Indexed: 11/27/2022]
Abstract
Electrocorticography signals, the intracranial recording of electrical signatures of the brain, are recorded by non-penetrating planar electrode arrays placed on the cortical surface. Flexible electrode arrays minimize the tissue damage upon implantation. This work shows the design and development of a 32-channel flexible microelectrode array to record electrocorticography signals from the rat's brain. The array was fabricated on a biocompatible flexible polyimide substrate. A titanium/gold layer was patterned as electrodes, and a thin polyimide layer was used for insulation. The fabricated microelectrode array was mounted on the exposed somatosensory cortex of the right hemisphere of a rat after craniotomy and incision of the dura. The signals were recorded using OpenBCI Cyton Daisy Biosensing Boards. The array faithfully recorded the baseline electrocorticography signals, the induced epileptic activities after applying a convulsant, and the recovered baseline signals after applying an antiepileptic drug. The signals recorded by such fabricated microelectrode array from anesthetized rats demonstrate its potential to monitor electrical signatures corresponding to epilepsy. Finally, the time-frequency analyses highlight the difference in spatiotemporal features of baseline and evoked epileptic discharges.
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Tringides CM, Mooney DJ. Materials for Implantable Surface Electrode Arrays: Current Status and Future Directions. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107207. [PMID: 34716730 DOI: 10.1002/adma.202107207] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/26/2021] [Indexed: 06/13/2023]
Abstract
Surface electrode arrays are mainly fabricated from rigid or elastic materials, and precisely manipulated ductile metal films, which offer limited stretchability. However, the living tissues to which they are applied are nonlinear viscoelastic materials, which can undergo significant mechanical deformation in dynamic biological environments. Further, the same arrays and compositions are often repurposed for vastly different tissues rather than optimizing the materials and mechanical properties of the implant for the target application. By first characterizing the desired biological environment, and then designing a technology for a particular organ, surface electrode arrays may be more conformable, and offer better interfaces to tissues while causing less damage. Here, the various materials used in each component of a surface electrode array are first reviewed, and then electrically active implants in three specific biological systems, the nervous system, the muscular system, and skin, are described. Finally, the fabrication of next-generation surface arrays that overcome current limitations is discussed.
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Affiliation(s)
- Christina M Tringides
- Harvard Program in Biophysics, Harvard University, Cambridge, MA, 02138, USA
- Harvard-MIT Division in Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
| | - David J Mooney
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, 02138, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
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10
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Sethia M, Sahin M. The size of via holes influence the amplitude and selectivity of neural signals in Micro-ECoG arrays. BMC Biomed Eng 2022; 4:3. [PMID: 35313997 PMCID: PMC8935835 DOI: 10.1186/s42490-022-00060-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 03/07/2022] [Indexed: 11/11/2022] Open
Abstract
Background Electrocorticography (ECoG) arrays are commonly used to record the brain activity both in animal and human subjects. There is a lack of guidelines in the literature as to how the array geometry, particularly the via holes in the substrate, affects the recorded signals. A finite element (FE) model was developed to simulate the electric field generated by neurons located at different depths in the rat brain cortex and a micro ECoG array (μECoG) was placed on the pia surface for recording the neural signal. The array design chosen was a typical array of 8 × 8 circular (100 μm in diam.) contacts with 500 μm pitch. The size of the via holes between the recording contacts was varied to see the effect. Results The results showed that recorded signal amplitudes were reduced if the substrate was smaller than about four times the depth of the neuron in the gray matter. The signal amplitude profiles had dips around the via holes and the amplitudes were also lower at the contact sites as compared to the design without the holes; an effect that increased with the hole size. Another noteworthy result is that the spatial selectivity of the multi-contact recordings could be improved or reduced by the selection of the via hole sizes, and the effect depended on the distance between the neuron pair targeted for selective recording and its depth. Conclusions The results suggest that the via-hole size clearly affects the recorded neural signal amplitudes and it can be leveraged as a parameter to reduce the inter-channel correlation and thus maximize the information content of neural signals with μECoG arrays.
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Abdul Nabi Ali A, Alam M, Klein SC, Behmann N, Krauss JK, Doll T, Blume H, Schwabe K. Predictive accuracy of CNN for cortical oscillatory activity in an acute rat model of parkinsonism. Neural Netw 2021; 146:334-340. [PMID: 34923220 DOI: 10.1016/j.neunet.2021.11.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 10/08/2021] [Accepted: 11/24/2021] [Indexed: 10/19/2022]
Abstract
In neurological and neuropsychiatric disorders neuronal oscillatory activity between basal ganglia and cortical circuits are altered, which may be useful as biomarker for adaptive deep brain stimulation. We investigated whether changes in the spectral power of oscillatory activity in the motor cortex (MCtx) and the sensorimotor cortex (SMCtx) of rats after injection of the dopamine (DA) receptor antagonist haloperidol (HALO) would be similar to those observed in Parkinson disease. Thereafter, we tested whether a convolutional neural network (CNN) model would identify brain signal alterations in this acute model of parkinsonism. A sixteen channel surface micro-electrocorticogram (ECoG) recording array was placed under the dura above the MCtx and SMCtx areas of one hemisphere under general anaesthesia in rats. Seven days after surgery, micro ECoG was recorded in individual free moving rats in three conditions: (1) basal activity, (2) after injection of HALO (0.5 mg/kg), and (3) with additional injection of apomorphine (APO) (1 mg/kg). Furthermore, a CNN-based classification consisting of 23,530 parameters was applied on the raw data. HALO injection decreased oscillatory theta band activity (4-8 Hz) and enhanced beta (12-30 Hz) and gamma (30-100 Hz) in MCtx and SMCtx, which was compensated after APO injection (P ¡ 0.001). Evaluation of classification performance of the CNN model provided accuracy of 92%, sensitivity of 90% and specificity of 93% on one-dimensional signals. The CNN proposed model requires a minimum of sensory hardware and may be integrated into future research on therapeutic devices for Parkinson disease, such as adaptive closed loop stimulation, thus contributing to more efficient way of treatment.
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Affiliation(s)
- Ali Abdul Nabi Ali
- Institute of Microelectronic Systems, Architectures and Systems, Leibniz University Hannover, Hannover, D-30167, Lower Saxony, Germany
| | - Mesbah Alam
- Department of Neurosurgery, Hannover Medical School, Hannover, D-30625, Lower Saxony, Germany.
| | - Simon C Klein
- Institute of Microelectronic Systems, Architectures and Systems, Leibniz University Hannover, Hannover, D-30167, Lower Saxony, Germany
| | - Nicolai Behmann
- Institute of Microelectronic Systems, Architectures and Systems, Leibniz University Hannover, Hannover, D-30167, Lower Saxony, Germany
| | - Joachim K Krauss
- Department of Neurosurgery, Hannover Medical School, Hannover, D-30625, Lower Saxony, Germany
| | - Theodor Doll
- Biomaterial Engineering, Hannover Medical School and Translational Medical Engineering Fraunhofer ITEM, Hannover, D-30625, Lower Saxony, Germany
| | - Holger Blume
- Institute of Microelectronic Systems, Architectures and Systems, Leibniz University Hannover, Hannover, D-30167, Lower Saxony, Germany
| | - Kerstin Schwabe
- Department of Neurosurgery, Hannover Medical School, Hannover, D-30625, Lower Saxony, Germany
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12
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Biocompatibility Testing of Liquid Metal as an Interconnection Material for Flexible Implant Technology. NANOMATERIALS 2021; 11:nano11123251. [PMID: 34947600 PMCID: PMC8706733 DOI: 10.3390/nano11123251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/16/2021] [Accepted: 11/25/2021] [Indexed: 11/23/2022]
Abstract
Galinstan, a liquid metal at room temperature, is a promising material for use in flexible electronics. Since it has been successfully integrated in devices for external use, e.g., as stretchable electronic skin in tactile sensation, the possibility of using galinstan for flexible implant technology comes to mind. Usage of liquid metals in a flexible implant would reduce the risk of broken conductive pathways in the implants and therefore reduce the possibility of implant failure. However, the biocompatibility of the liquid metal under study, i.e., galinstan, has not been proven in state-of-the-art literature. Therefore, in this paper, a material combination of galinstan and silicone rubber is under investigation regarding the success of sterilization methods and to establish biocompatibility testing for an in vivo application. First cell biocompatibility tests (WST-1 assays) and cell toxicity tests (LDH assays) show promising results regarding biocompatibility. This work paves the way towards the successful integration of stretchable devices using liquid metals embedded in a silicone rubber encapsulant for flexible surface electro-cortical grid arrays and other flexible implants.
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13
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Tringides CM, Vachicouras N, de Lázaro I, Wang H, Trouillet A, Seo BR, Elosegui-Artola A, Fallegger F, Shin Y, Casiraghi C, Kostarelos K, Lacour SP, Mooney DJ. Viscoelastic surface electrode arrays to interface with viscoelastic tissues. NATURE NANOTECHNOLOGY 2021; 16:1019-1029. [PMID: 34140673 PMCID: PMC9233755 DOI: 10.1038/s41565-021-00926-z] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 05/05/2021] [Indexed: 05/10/2023]
Abstract
Living tissues are non-linearly elastic materials that exhibit viscoelasticity and plasticity. Man-made, implantable bioelectronic arrays mainly rely on rigid or elastic encapsulation materials and stiff films of ductile metals that can be manipulated with microscopic precision to offer reliable electrical properties. In this study, we have engineered a surface microelectrode array that replaces the traditional encapsulation and conductive components with viscoelastic materials. Our array overcomes previous limitations in matching the stiffness and relaxation behaviour of soft biological tissues by using hydrogels as the outer layers. We have introduced a hydrogel-based conductor made from an ionically conductive alginate matrix enhanced with carbon nanomaterials, which provide electrical percolation even at low loading fractions. Our combination of conducting and insulating viscoelastic materials, with top-down manufacturing, allows for the fabrication of electrode arrays compatible with standard electrophysiology platforms. Our arrays intimately conform to the convoluted surface of the heart or brain cortex and offer promising bioengineering applications for recording and stimulation.
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Affiliation(s)
- Christina M Tringides
- Harvard Program in Biophysics, Harvard University, Cambridge, MA, USA
- Harvard-MIT Division in Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA
| | - Nicolas Vachicouras
- Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Irene de Lázaro
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Hua Wang
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Alix Trouillet
- Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Bo Ri Seo
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
| | - Alberto Elosegui-Artola
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Institute for Bioengineering of Catalonia, Barcelona, Spain
| | - Florian Fallegger
- Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Yuyoung Shin
- Department of Chemistry, The University of Manchester, Manchester, UK
| | - Cinzia Casiraghi
- Department of Chemistry, The University of Manchester, Manchester, UK
| | - Kostas Kostarelos
- Nanomedicine Lab, National Graphene Institute and Faculty of Biology, Medicine & Health, The University of Manchester, Manchester, UK
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), Bellaterra, Barcelona, Spain
| | - Stéphanie P Lacour
- Laboratory for Soft Bioelectronic Interfaces, Institute of Microengineering, Institute of Bioengineering, Centre for Neuroprosthetics, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - David J Mooney
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA, USA.
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
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14
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Tan LL, Oswald MJ, Kuner R. Neurobiology of brain oscillations in acute and chronic pain. Trends Neurosci 2021; 44:629-642. [PMID: 34176645 DOI: 10.1016/j.tins.2021.05.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/19/2021] [Accepted: 05/07/2021] [Indexed: 01/08/2023]
Abstract
Pain is a complex perceptual phenomenon. Coordinated activity among local and distant brain networks is a central element of the neural underpinnings of pain. Brain oscillatory rhythms across diverse frequency ranges provide a functional substrate for coordinating activity across local neuronal ensembles and anatomically distant brain areas in pain networks. This review addresses parallels between insights from human and rodent analyses of oscillatory rhythms in acute and chronic pain and discusses recent rodent-based studies that have shed light on mechanistic underpinnings of brain oscillatory dynamics in pain-related behaviors. We highlight the potential for therapeutic modulation of oscillatory rhythms, and identify outstanding questions and challenges to be addressed in future research.
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Affiliation(s)
- Linette Liqi Tan
- Institute of Pharmacology, Heidelberg University, Im Neuenheimer Feld 366, D-69120 Heidelberg, Germany.
| | - Manfred Josef Oswald
- Institute of Pharmacology, Heidelberg University, Im Neuenheimer Feld 366, D-69120 Heidelberg, Germany
| | - Rohini Kuner
- Institute of Pharmacology, Heidelberg University, Im Neuenheimer Feld 366, D-69120 Heidelberg, Germany.
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15
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Jeong UJ, Lee J, Chou N, Kim K, Shin H, Chae U, Yu HY, Cho IJ. A minimally invasive flexible electrode array for simultaneous recording of ECoG signals from multiple brain regions. LAB ON A CHIP 2021; 21:2383-2397. [PMID: 33955442 DOI: 10.1039/d1lc00117e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The minimal invasiveness of electrocorticography (ECoG) enabled its widespread use in clinical areas as well as in neuroscience research. However, most existing ECoG arrays require that the entire surface area of the brain that is to be recorded be exposed through a large craniotomy. We propose a device that overcomes this limitation, i.e., a minimally invasive, polyimide-based flexible array of electrodes that can enable the recording of ECoG signals in multiple regions of the brain with minimal exposure of the surface of the brain. Magnetic force-assisted positioning of a flexible electrode array enables recording from distant brain regions with a small cranial window. Also, a biodegradable organic compound used for attaching a magnet on the electrodes allows simple retrieval of the magnet. We demonstrate with an in vivo chronic recording that an implanted ECoG electrode array can record ECoG signals from the visual cortex and the motor cortex during a rat's free behavior. Our results indicate that the proposed device induced minimal damage to the animal. We expect the proposed device to be utilized for experiments for large-scale brain circuit analyses as well as clinical applications for intra-operative monitoring of epileptic activity.
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Affiliation(s)
- Ui-Jin Jeong
- Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea. and School of Electrical Engineering, Korea University, Seoul, Republic of Korea
| | - Jungpyo Lee
- Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.
| | - Namsun Chou
- Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.
| | - Kanghwan Kim
- Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.
| | - Hyogeun Shin
- Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea. and Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea
| | - Uikyu Chae
- Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea. and School of Electrical Engineering, Korea University, Seoul, Republic of Korea
| | - Hyun-Yong Yu
- School of Electrical Engineering, Korea University, Seoul, Republic of Korea
| | - Il-Joo Cho
- Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea. and Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Seoul, Republic of Korea and School of Electrical and Electronics Engineering, Yonsei University, Seoul, Republic of Korea and Yonsei-KIST Convergence Research Institute, Yonsei University, Seoul, Republic of Korea
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16
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Foremny K, Konerding WS, Behrens A, Baumhoff P, Froriep UP, Kral A, Doll T. Carbon-Nanotube-Coated Surface Electrodes for Cortical Recordings In Vivo. NANOMATERIALS 2021; 11:nano11041029. [PMID: 33920671 PMCID: PMC8073035 DOI: 10.3390/nano11041029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/12/2021] [Accepted: 04/15/2021] [Indexed: 11/16/2022]
Abstract
Current developments of electrodes for neural recordings address the need of biomedical research and applications for high spatial acuity in electrophysiological recordings. One approach is the usage of novel materials to overcome electrochemical constraints of state-of-the-art metal contacts. Promising materials are carbon nanotubes (CNTs), as they are well suited for neural interfacing. The CNTs increase the effective contact surface area to decrease high impedances while keeping minimal contact diameters. However, to prevent toxic dissolving of CNTs, an appropriate surface coating is required. In this study, we tested flexible surface electrocorticographic (ECoG) electrodes, coated with a CNT-silicone rubber composite. First, we describe the outcome of surface etching, which exposes the contact nanostructure while anchoring the CNTs. Subsequently, the ECoG electrodes were used for acute in vivo recordings of auditory evoked potentials from the guinea pig auditory cortex. Both the impedances and the signal-to-noise ratios of coated contacts were similar to uncoated gold contacts. This novel approach for a safe application of CNTs, embedded in a surface etched silicone rubber, showed promising results but did not lead to improvements during acute recordings.
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Affiliation(s)
- Katharina Foremny
- Institute of AudioNeuroTechnology and Department of Experimental Otology, ENT Clinic, Hannover Medical School, 30625 Hannover, Germany; (W.S.K.); (A.B.); (P.B.); (A.K.); (T.D.)
- Correspondence:
| | - Wiebke S. Konerding
- Institute of AudioNeuroTechnology and Department of Experimental Otology, ENT Clinic, Hannover Medical School, 30625 Hannover, Germany; (W.S.K.); (A.B.); (P.B.); (A.K.); (T.D.)
| | - Ailke Behrens
- Institute of AudioNeuroTechnology and Department of Experimental Otology, ENT Clinic, Hannover Medical School, 30625 Hannover, Germany; (W.S.K.); (A.B.); (P.B.); (A.K.); (T.D.)
| | - Peter Baumhoff
- Institute of AudioNeuroTechnology and Department of Experimental Otology, ENT Clinic, Hannover Medical School, 30625 Hannover, Germany; (W.S.K.); (A.B.); (P.B.); (A.K.); (T.D.)
| | - Ulrich P. Froriep
- Division of Translational Biomedical Engineering, Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, 30625 Hannover, Germany;
| | - Andrej Kral
- Institute of AudioNeuroTechnology and Department of Experimental Otology, ENT Clinic, Hannover Medical School, 30625 Hannover, Germany; (W.S.K.); (A.B.); (P.B.); (A.K.); (T.D.)
| | - Theodor Doll
- Institute of AudioNeuroTechnology and Department of Experimental Otology, ENT Clinic, Hannover Medical School, 30625 Hannover, Germany; (W.S.K.); (A.B.); (P.B.); (A.K.); (T.D.)
- Division of Translational Biomedical Engineering, Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, 30625 Hannover, Germany;
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17
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Hejazi M, Tong W, Ibbotson MR, Prawer S, Garrett DJ. Advances in Carbon-Based Microfiber Electrodes for Neural Interfacing. Front Neurosci 2021; 15:658703. [PMID: 33912007 PMCID: PMC8072048 DOI: 10.3389/fnins.2021.658703] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
Neural interfacing devices using penetrating microelectrode arrays have emerged as an important tool in both neuroscience research and medical applications. These implantable microelectrode arrays enable communication between man-made devices and the nervous system by detecting and/or evoking neuronal activities. Recent years have seen rapid development of electrodes fabricated using flexible, ultrathin carbon-based microfibers. Compared to electrodes fabricated using rigid materials and larger cross-sections, these microfiber electrodes have been shown to reduce foreign body responses after implantation, with improved signal-to-noise ratio for neural recording and enhanced resolution for neural stimulation. Here, we review recent progress of carbon-based microfiber electrodes in terms of material composition and fabrication technology. The remaining challenges and future directions for development of these arrays will also be discussed. Overall, these microfiber electrodes are expected to improve the longevity and reliability of neural interfacing devices.
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Affiliation(s)
- Maryam Hejazi
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
| | - Wei Tong
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC, Australia
| | - Michael R. Ibbotson
- National Vision Research Institute, The Australian College of Optometry, Carlton, VIC, Australia
- Department of Optometry and Vision Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Steven Prawer
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
| | - David J. Garrett
- School of Physics, The University of Melbourne, Parkville, VIC, Australia
- School of Engineering, RMIT University, Melbourne, VIC, Australia
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18
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Kaiju T, Inoue M, Hirata M, Suzuki T. High-density mapping of primate digit representations with a 1152-channel µECoG array. J Neural Eng 2021; 18. [PMID: 33530064 DOI: 10.1088/1741-2552/abe245] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 02/02/2021] [Indexed: 12/11/2022]
Abstract
Objective.Advances in brain-machine interfaces (BMIs) are expected to support patients with movement disorders. Electrocorticogram (ECoG) measures electrophysiological activities over a large area using a low-invasive flexible sheet placed on the cortex. ECoG has been considered as a feasible signal source of the clinical BMI device. To capture neural activities more precisely, the feasibility of higher-density arrays has been investigated. However, currently, the number of electrodes is limited to approximately 300 due to wiring difficulties, device size, and system costs.Approach.We developed a high-density recording system with a large coverage (14 × 7 mm2) and using 1152 electrodes by directly integrating dedicated flexible arrays with the neural-recording application-specific integrated circuits and their interposers.Main results.Comparative experiments with a 128-channel array demonstrated that the proposed device could delineate the entire digit representation of a nonhuman primate. Subsampling analysis revealed that higher-amplitude signals can be measured using higher-density arrays.Significance.We expect that the proposed system that simultaneously establishes large-scale sampling, high temporal-precision of electrophysiology, and high spatial resolution comparable to optical imaging will be suitable for next-generation brain-sensing technology.
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Affiliation(s)
- Taro Kaiju
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology, and Osaka University, Osaka, Japan
| | - Masato Inoue
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology, and Osaka University, Osaka, Japan.,Department of Neurological Diagnosis and Restoration, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Masayuki Hirata
- Center for Information and Neural Networks (CiNet), National Institute of Information and Communications Technology, and Osaka University, Osaka, Japan.,Department of Neurological Diagnosis and Restoration, Osaka University Graduate School of Medicine, Osaka, Japan
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19
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Keramatzadeh K, Kiakojouri A, Nahvi MS, Khazaei Y, Feizi-Nejad A, Maghami MH, Mohammadi R, Sharifshazileh M, Nasiri S, Akbari Boroumand F, Nadimi E, Rezaei M, Shojaei A, Mirnajafi-Zadeh J, Sodagar AM. Wireless, miniaturized, semi-implantable electrocorticography microsystem validated in vivo. Sci Rep 2020; 10:21261. [PMID: 33277523 PMCID: PMC7718888 DOI: 10.1038/s41598-020-77953-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 10/29/2020] [Indexed: 11/09/2022] Open
Abstract
This paper reports on the design, development, and test of a multi-channel wireless micro-electrocorticography (µECoG) system. The system consists of a semi-implantable, ultra-compact recording unit and an external unit, interfaced through a 2.4 GHz radio frequency data telemetry link with 2 Mbps (partially used) data transfer rate. Encased in a 3D-printed 2.9 cm × 2.9 cm × 2.5 cm cubic package, the semi-implantable recording unit consists of a microelectrode array, a vertically-stacked PCB platform containing off-the-shelf components, and commercially-available small-size 3.7-V, 50 mAh lithium-ion batteries. Two versions of microelectrode array were developed for the recording unit: a rigid 4 × 2 microelectrode array, and a flexible 12 × 6 microelectrode array, 36 of which routed to bonding pads for actual recording. The external unit comprises a transceiver board, a data acquisition board, and a host computer, on which reconstruction of the received signals is performed. After development, assembly, and integration, the system was tested and validated in vivo on anesthetized rats. The system successfully recorded both spontaneous and evoked activities from the brain of the subject.
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Affiliation(s)
- Keivan Keramatzadeh
- Research Labarotory for Integrated Circuits and Systems (ICAS), Faculty of EE, K.N. Toosi University of Technology, Tehran, Iran
| | - Ali Kiakojouri
- Research Labarotory for Integrated Circuits and Systems (ICAS), Faculty of EE, K.N. Toosi University of Technology, Tehran, Iran
| | - Mohammad Sadegh Nahvi
- Research Labarotory for Integrated Circuits and Systems (ICAS), Faculty of EE, K.N. Toosi University of Technology, Tehran, Iran
| | - Yousef Khazaei
- Research Labarotory for Integrated Circuits and Systems (ICAS), Faculty of EE, K.N. Toosi University of Technology, Tehran, Iran
| | - Ali Feizi-Nejad
- Research Labarotory for Integrated Circuits and Systems (ICAS), Faculty of EE, K.N. Toosi University of Technology, Tehran, Iran
| | - Mohammad Hossein Maghami
- Research Labarotory for Integrated Circuits and Systems (ICAS), Faculty of EE, K.N. Toosi University of Technology, Tehran, Iran.,Faculty of Electrical Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran
| | - Reza Mohammadi
- Department of ECE, University of Waterloo, Waterloo, ON, Canada
| | | | - Soraya Nasiri
- Research Labarotory for Integrated Circuits and Systems (ICAS), Faculty of EE, K.N. Toosi University of Technology, Tehran, Iran
| | | | - Ebrahim Nadimi
- Faculty of EE, K.N. Toosi University of Technology, Tehran, Iran
| | - Mahmoud Rezaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Amir Shojaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Amir M Sodagar
- Department of EECS, York University, Toronto, ON, Canada.
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20
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Martini ML, Oermann EK, Opie NL, Panov F, Oxley T, Yaeger K. Sensor Modalities for Brain-Computer Interface Technology: A Comprehensive Literature Review. Neurosurgery 2020; 86:E108-E117. [PMID: 31361011 DOI: 10.1093/neuros/nyz286] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 05/04/2019] [Indexed: 12/23/2022] Open
Abstract
Brain-computer interface (BCI) technology is rapidly developing and changing the paradigm of neurorestoration by linking cortical activity with control of an external effector to provide patients with tangible improvements in their ability to interact with the environment. The sensor component of a BCI circuit dictates the resolution of brain pattern recognition and therefore plays an integral role in the technology. Several sensor modalities are currently in use for BCI applications and are broadly either electrode-based or functional neuroimaging-based. Sensors vary in their inherent spatial and temporal resolutions, as well as in practical aspects such as invasiveness, portability, and maintenance. Hybrid BCI systems with multimodal sensory inputs represent a promising development in the field allowing for complimentary function. Artificial intelligence and deep learning algorithms have been applied to BCI systems to achieve faster and more accurate classifications of sensory input and improve user performance in various tasks. Neurofeedback is an important advancement in the field that has been implemented in several types of BCI systems by showing users a real-time display of their recorded brain activity during a task to facilitate their control over their own cortical activity. In this way, neurofeedback has improved BCI classification and enhanced user control over BCI output. Taken together, BCI systems have progressed significantly in recent years in terms of accuracy, speed, and communication. Understanding the sensory components of a BCI is essential for neurosurgeons and clinicians as they help advance this technology in the clinical setting.
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Affiliation(s)
- Michael L Martini
- Department of Neurosurgery, Mount Sinai Hospital, New York, New York
| | - Eric Karl Oermann
- Department of Neurosurgery, Mount Sinai Hospital, New York, New York
| | - Nicholas L Opie
- Vascular Bionics Laboratory, Department of Medicine, Melbourne University, Melbourne, Australia
| | - Fedor Panov
- Department of Neurosurgery, Mount Sinai Hospital, New York, New York
| | - Thomas Oxley
- Department of Neurosurgery, Mount Sinai Hospital, New York, New York.,Vascular Bionics Laboratory, Department of Medicine, Melbourne University, Melbourne, Australia
| | - Kurt Yaeger
- Department of Neurosurgery, Mount Sinai Hospital, New York, New York
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21
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Konerding W, Arenberg JG, Kral A, Baumhoff P. Late electrically-evoked compound action potentials as markers for acute micro-lesions of spiral ganglion neurons. Hear Res 2020; 413:108057. [PMID: 32883545 DOI: 10.1016/j.heares.2020.108057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 07/13/2020] [Accepted: 08/11/2020] [Indexed: 12/20/2022]
Abstract
Cochlear implants (CIs) are the treatment of choice for profoundly hearing impaired people. It has been proposed that speech perception in CI users is influenced by the neural health (deafferentation, demyelination and degeneration) of the cochlea, which may be heterogeneous along an individual cochlea. Several options have been put forward to account for these local differences in neural health when fitting the speech processor settings, however with mixed results. The interpretation of the results is hampered by the fact that reliable markers of locally restricted changes in spiral ganglion neuron (SGN) health are lacking. The aim of the study was (i) to establish mechanical micro-lesions in the guinea pig as a model of heterogeneous SGN deafferentation and degeneration and (ii) to assess potential electrophysiological markers that can also be used in human subjects. First, we defined the extent of micro-lesions in normal hearing animals using acoustically-evoked compound action potentials (aCAPs); second, we measured electrically-evoked CAPs (eCAPs) before and after focal lesioning in neomycin-deafened and implanted animals. Therefore, we inserted guinea pig adjusted 6-contact CIs through a cochleostomy in the scala tympani. The eCAP was recorded from a ball electrode at the round window niche in response to monopolar or bipolar, 50 µs/phase biphasic pulses of alternating anodic- and cathodic-leading polarity. To exclude the large electrical artifact from the analysis, we focused on the late eCAP component. We systematically isolated the eCAP parameter that showed local pre- versus post-lesion changes and lesion-target specificity. Histological evaluation of the cleared cochleae revealed focal damage of an average size of 0.0036 mm3 with an apical-basal span of maximal 440 µm. We found that the threshold of the late N2P2 eCAP component was significantly elevated after lesioning when stimulating at basal (near the lesion), but not apical (distant to the lesion) CI contacts. To circumvent the potentially conflicting influence of the apical-basal gradient in eCAP thresholds, we used the polarity effect (PE=cathodic-anodic) as a relative measure. During monopolar stimulation, but not bipolar stimulation, the PE was sensitive to the lesion target and showed significantly better cathodic than anodic thresholds after soma lesions. We conclude that the difference in N2P2 thresholds in response to cathodic versus anodic-leading monopolar stimulation corresponds to the presence of SGN soma damage, and may therefore be a marker for SGN loss. We consider this electrophysiological estimate of local neural health a potentially relevant tool for human applications because of the temporal separation from the stimulation artifact and possible implementation into common eCAP measurements.
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Affiliation(s)
- Wiebke Konerding
- Department of Experimental Otology, Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany.
| | - Julie G Arenberg
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA.
| | - Andrej Kral
- Department of Experimental Otology, Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany; Cluster of Excellence "Hearing4all", Germany.
| | - Peter Baumhoff
- Department of Experimental Otology, Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany.
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Pavone L, Moyanova S, Mastroiacovo F, Fazi L, Busceti C, Gaglione A, Martinello K, Fucile S, Bucci D, Prioriello A, Nicoletti F, Fornai F, Morales P, Senesi R. Chronic neural interfacing with cerebral cortex using single-walled carbon nanotube-polymer grids. J Neural Eng 2020; 17:036032. [PMID: 32485702 DOI: 10.1088/1741-2552/ab98db] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE The development of electrode arrays able to reliably record brain electrical activity is a critical issue in brain machine interface (BMI) technology. In the present study we undertook a comprehensive physico-chemical, physiological, histological and immunohistochemical characterization of new single-walled carbon nanotubes (SWCNT)-based electrode arrays grafted onto medium-density polyethylene (MD-PE) films. APPROACH The long-term electrical stability, flexibility, and biocompatibility of the SWCNT arrays were investigated in vivo in laboratory rats by two-months recording and analysis of subdural electrocorticogram (ECoG). Ex-vivo characterization of a thin flexible and single probe SWCNT/polymer electrode is also provided. MAIN RESULTS The SWCNT arrays were able to capture high quality and very stable ECoG signals across 8 weeks. The histological and immunohistochemical analyses demonstrated that SWCNT arrays show promising biocompatibility properties and may be used in chronic conditions. The SWCNT-based arrays are flexible and stretchable, providing low electrode-tissue impedance, and, therefore, high compliance with the irregular topography of the cortical surface. Finally, reliable evoked synaptic local field potentials in rat brain slices were recorded using a special SWCNT-polymer-based flexible electrode. SIGNIFICANCE The results demonstrate that the SWCNT arrays grafted in MD-PE are suitable for manufacturing flexible devices for subdural ECoG recording and might represent promising candidates for long-term neural implants for epilepsy monitoring or neuroprosthetic BMI.
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Affiliation(s)
- Luigi Pavone
- Department of Life and Health 'V. Tiberio', University of Molise, Campobasso, Italy. IRCCS Neuromed, Via Atinense 18, 86077, Pozzilli (IS), Italy. These authors contributed equally. Author to whom any correspondence should be addressed
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Hartung JE, Gold MS. GCaMP as an indirect measure of electrical activity in rat trigeminal ganglion neurons. Cell Calcium 2020; 89:102225. [PMID: 32505783 DOI: 10.1016/j.ceca.2020.102225] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 11/19/2022]
Abstract
While debate continues over whether somatosensory information is transmitted via labeled line, population coding, frequency coding, or some combination therein, researchers have begun to address this question at the level of the primary afferent by using optical approaches that enable the assessment of neural activity in hundreds to even thousands of neurons simultaneously. However, with limited availability of tools to optically assess electrical activity in large populations of neurons, researchers have turned to genetically encoded Ca2+ indicators (GECIs) including GCaMP to enable the detection of increases in cytosolic Ca2+ concentrations as a correlate for neuronal activity. One of the most widely used GECIs is GCaMP6, which is available in three different versions tuned for sensitivity (GCaMP6s), speed (GCaMP6f), or a balance of the two (GCaMP6m). In order to determine if these issues were unique to GCaMP6 itself, or if they were inherent to more than one generation of GCaMP, we also characterized jGCaMP7. In the present study, we sought to determine the utility of the three GCaMP6 isoforms to detect changes in activity in primary afferents at frequencies ranging from 0.1-30 Hz. Given the heterogeneity of sensory neurons, we also compared the performance of each GCaMP6 isoform in subpopulations of neurons defined by properties used to identify putative nociceptive afferents: cell body size, isolectin B4 (IB4) binding, and capsaicin sensitivity. Finally, we compared results generated with GCaMP6 with that generated from neurons expressing the next generation of GCaMP, jGCaMP7s and jGCaMP7f. A viral approach, with AAV9-CAG-GCaMP6s/m/f, was used to drive GECI expression in acutely dissociated rat trigeminal ganglion (TG) neurons, and neural activity was driven by electrical field stimulation. Infection efficiency with the AAV serotype was high >95 %, and the impact of GCaMP6 expression in TG neurons over the period of study (<10 days) on the regulation of intracellular Ca2+, as assessed with fura-2, was minimal. Having confirmed that the field stimulation evoked Ca2+ transients were dependent on Ca2+ influx secondary to the activation of action potentials and voltage-gated Ca2+ channels, we also confirmed that the signal-to-noise ratio for each of the isoforms was excellent, enabling detection of a single spike in>90% of neurons. However, the utility of the GCaMP6 isoforms to enable an assessment of the firing frequency let alone changes in firing frequency of each neuron was relatively limited and isoform specific: GCaMP6s and 6m had the lowest resolution, enabling detection of spikes at 3 Hz in 15% and 32% of neurons respectively, but it was possible to resolve discrete single spikes up to 10 Hz in 36% of GCaMP6f neurons. Unfortunately, using other parameters of the Ca2+ transient, such as magnitude of the transient or the rate of rise, did not improve the range over which these indicators could be used to assess changes in spike number or firing frequency. Furthermore, in the presence of ongoing neural activity, it was even more difficult to detect a change in firing frequency. The frequency response relationship for the increase in Ca2+ was highly heterogeneous among sensory neurons and was influenced by both the GCaMP6 isoform used to assess it, the timing between the delivery of stimulation trains (inter-burst interval), and afferent subpopulation. Notably, the same deficiencies were observed with jGCaMP7s and 7f in resolving the degree of activity as were present for the GCaMP6 isoforms. Together, these data suggest that while both GCaMP6 and jGCaMP7 are potentially useful tools in sensory neurons to determine the presence or absence of neural activity, the ability to discriminate changes in firing frequency ≥ 3 Hz is extremely limited. As a result, GECIs should probably not be used in sensory neurons to assess changes in activity within or between subpopulations of neurons.
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Affiliation(s)
- Jane E Hartung
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, United States.
| | - Michael S Gold
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, United States.
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Hermiz J, Hossain L, Arneodo EM, Ganji M, Rogers N, Vahidi N, Halgren E, Gentner TQ, Dayeh SA, Gilja V. Stimulus Driven Single Unit Activity From Micro-Electrocorticography. Front Neurosci 2020; 14:55. [PMID: 32180695 PMCID: PMC7059620 DOI: 10.3389/fnins.2020.00055] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 01/14/2020] [Indexed: 12/18/2022] Open
Abstract
High-fidelity measurements of neural activity can enable advancements in our understanding of the neural basis of complex behaviors such as speech, audition, and language, and are critical for developing neural prostheses that address impairments to these abilities due to disease or injury. We develop a novel high resolution, thin-film micro-electrocorticography (micro-ECoG) array that enables high-fidelity surface measurements of neural activity from songbirds, a well-established animal model for studying speech behavior. With this device, we provide the first demonstration of sensory-evoked modulation of surface-recorded single unit responses. We establish that single unit activity is consistently sensed from micro-ECoG electrodes over the surface of sensorimotor nucleus HVC (used as a proper name) in anesthetized European starlings, and validate responses with correlated firing in single units recorded simultaneously at surface and depth. The results establish a platform for high-fidelity recording from the surface of subcortical structures that will accelerate neurophysiological studies, and development of novel electrode arrays and neural prostheses.
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Affiliation(s)
- John Hermiz
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States
| | - Lorraine Hossain
- Department of Materials Science and Engineering, University of California, San Diego, La Jolla, CA, United States
| | - Ezequiel M Arneodo
- Biocircuits Institute, University of California, San Diego, La Jolla, CA, United States
| | - Mehran Ganji
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States
| | - Nicholas Rogers
- Department of Physics, University of California, San Diego, La Jolla, CA, United States
| | - Nasim Vahidi
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States
| | - Eric Halgren
- Department of Radiology, University of California, San Diego, La Jolla, CA, United States.,Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
| | - Timothy Q Gentner
- Department of Psychology, University of California, San Diego, La Jolla, CA, United States.,Kavli Institute for Brain and Mind, La Jolla, CA, United States.,Neurobiology Section, University of California, San Diego, La Jolla, CA, United States
| | - Shadi A Dayeh
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States.,Department of Materials Science and Engineering, University of California, San Diego, La Jolla, CA, United States.,Department of Nanoengineering, University of California, San Diego, La Jolla, CA, United States
| | - Vikash Gilja
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States
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25
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Celotto M, De Luca C, Muratore P, Resta F, Allegra Mascaro AL, Pavone FS, De Bonis G, Paolucci PS. Analysis and Model of Cortical Slow Waves Acquired with Optical Techniques. Methods Protoc 2020; 3:E14. [PMID: 32023996 PMCID: PMC7189682 DOI: 10.3390/mps3010014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/10/2020] [Accepted: 01/22/2020] [Indexed: 12/25/2022] Open
Abstract
Slow waves (SWs) are spatio-temporal patterns of cortical activity that occur both during natural sleep and anesthesia and are preserved across species. Even though electrophysiological recordings have been largely used to characterize brain states, they are limited in the spatial resolution and cannot target specific neuronal population. Recently, large-scale optical imaging techniques coupled with functional indicators overcame these restrictions, and new pipelines of analysis and novel approaches of SWs modelling are needed to extract relevant features of the spatio-temporal dynamics of SWs from these highly spatially resolved data-sets. Here we combined wide-field fluorescence microscopy and a transgenic mouse model expressing a calcium indicator (GCaMP6f) in excitatory neurons to study SW propagation over the meso-scale under ketamine anesthesia. We developed a versatile analysis pipeline to identify and quantify the spatio-temporal propagation of the SWs. Moreover, we designed a computational simulator based on a simple theoretical model, which takes into account the statistics of neuronal activity, the response of fluorescence proteins and the slow waves dynamics. The simulator was capable of synthesizing artificial signals that could reliably reproduce several features of the SWs observed in vivo, thus enabling a calibration tool for the analysis pipeline. Comparison of experimental and simulated data shows the robustness of the analysis tools and its potential to uncover mechanistic insights of the Slow Wave Activity (SWA).
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Affiliation(s)
- Marco Celotto
- Department of Physics, “Sapienza” University of Rome, 00185 Rome, Italy; (M.C.); (C.D.L.); (P.M.)
- IIT—Neural Computation Lab, CNCS@UniTn, 38068 Rovereto, Italy
| | - Chiara De Luca
- Department of Physics, “Sapienza” University of Rome, 00185 Rome, Italy; (M.C.); (C.D.L.); (P.M.)
- INFN, 00185 Rome, Italy;
- PhD Program in Behavioural Neuroscience,“Sapienza” University of Rome, 00185 Rome, Italy
| | - Paolo Muratore
- Department of Physics, “Sapienza” University of Rome, 00185 Rome, Italy; (M.C.); (C.D.L.); (P.M.)
- PhD Program in Cognitive Neuroscience, SISSA, 34136 Trieste, Italy
| | - Francesco Resta
- LENS, University of Florence, 50019 Florence, Italy; (F.R.); (A.L.A.M.); (F.S.P.)
| | - Anna Letizia Allegra Mascaro
- LENS, University of Florence, 50019 Florence, Italy; (F.R.); (A.L.A.M.); (F.S.P.)
- Istituto di Neuroscienze, CNR, 56124 Pisa, Italy
| | - Francesco Saverio Pavone
- LENS, University of Florence, 50019 Florence, Italy; (F.R.); (A.L.A.M.); (F.S.P.)
- Department of Physics, University of Florence, 50019 Florence, Italy
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Li M, Liang Y, Yang L, Wang H, Yang Z, Zhao K, Shang Z, Wan H. Automatic bad channel detection in implantable brain-computer interfaces using multimodal features based on local field potentials and spike signals. Comput Biol Med 2020; 116:103572. [DOI: 10.1016/j.compbiomed.2019.103572] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/12/2019] [Accepted: 12/01/2019] [Indexed: 11/29/2022]
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Voigt MB, Kral A. Cathodic-leading pulses are more effective than anodic-leading pulses in intracortical microstimulation of the auditory cortex. J Neural Eng 2019; 16:036002. [PMID: 30790776 DOI: 10.1088/1741-2552/ab0944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Intracortical microstimulation (ICMS) is widely used in neuroscientific research. Earlier work from our lab showed the possibility to combine ICMS with neuronal recordings on the same shank of multi-electrode arrays and consequently inside the same cortical column in vivo. The standard stimulus pulse shape for ICMS is a symmetric, biphasic current pulse. Here, we investigated the role of the leading-phase polarity (cathodic- versus anodic-leading) of such single ICMS pulses on the activation of the cortical network. APPROACH Local field potentials (LFPs) and multi-unit responses were recorded in the primary auditory cortex (A1) of adult guinea pigs (n = 15) under ketamine/xylazine anesthesia using linear multi-electrode arrays. Physiological responses of A1 were recorded during acoustic stimulation and ICMS. For the ICMS, the leading-phase polarity, the stimulated electrode and the stimulation current where varied systematically on any one of the 16 electrodes while recording at the same time with the 15 remaining electrodes. MAIN RESULTS Cathodic-leading ICMS consistently led to higher response amplitudes. In superficial cortical layers and for a given current amplitude, cathodic-leading and anodic-leading ICMS showed comparable activation patterns, while in deep layers only cathodic-leading ICMS reliably generated local neuronal activity. ICMS had a significantly smaller dynamic range than acoustic stimulation regardless of leading-phase polarity. SIGNIFICANCE The present study provides in vivo evidence for a differential neuronal activation mechanism of the different leading-phase polarities, with cathodic-leading stimulation being more effective, and suggests that the waveform of the stimulus should be considered systematically for cortical neuroprosthesis development.
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Affiliation(s)
- Mathias Benjamin Voigt
- Department of Experimental Otology, Institute of AudioNeuroTechnology (VIANNA), Hannover Medical School, Stadtfelddamm 34, 30625 Hannover, Germany. Cluster of Excellence 'Hearing4all', Hannover, Germany
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Intracochlear near infrared stimulation: Feasibility of optoacoustic stimulation in vivo. Hear Res 2018; 371:40-52. [PMID: 30458383 DOI: 10.1016/j.heares.2018.11.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 10/04/2018] [Accepted: 11/08/2018] [Indexed: 01/12/2023]
Abstract
Intracochlear optical stimulation has been suggested as an alternative approach to hearing prosthetics in recent years. This study investigated the properties of a near infrared laser (NIR) induced optoacoustic effect. Pressure recordings were performed at the external meatus of anaesthetized guinea pigs during intracochlear NIR stimulation. The sound pressure and power spectra were determined. The results were compared to multi unit responses in the inferior colliculus (IC). Additionally, the responses to NIR stimulation were compared to IC responses induced by intracochlear electric stimulation at the same cochlear position to investigate a potentially confounding contribution of direct neural NIR stimulation. The power spectra of the sound recorded at the external meatus (n = 7) had most power at frequencies below 10 kHz and showed little variation for different stimulation sites. The mean spike rates of IC units responding to intracochlear NIR stimulation (n = 222) of 17 animals were significantly correlated with the power of the externally recorded signal at frequencies corresponding to the best frequencies of the IC units. The response strength as well as the sound pressure at the external meatus depended on the pulse peak power of the optical stimulus. The sound pressure recorded at the external meatus reached levels above 70 dB SPL peak equivalent. In hearing animals a cochlear activation apical to the location of the fiber was found. The absence of any NIR responses after pharmacologically deafening and the comparison to electric stimulation at the NIR stimulation site revealed no indication of a confounding direct neural NIR stimulation. Intracochlear optoacoustic stimulation might become useful in combined electro-acoustic stimulation devices in the future.
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Intracortical Microstimulation Modulates Cortical Induced Responses. J Neurosci 2018; 38:7774-7786. [PMID: 30054394 DOI: 10.1523/jneurosci.0928-18.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/19/2018] [Accepted: 07/06/2018] [Indexed: 12/31/2022] Open
Abstract
Recent advances in cortical prosthetics relied on intracortical microstimulation (ICMS) to activate the cortical neural network and convey information to the brain. Here we show that activity elicited by low-current ICMS modulates induced cortical responses to a sensory stimulus in the primary auditory cortex (A1). A1 processes sensory stimuli in a stereotyped manner, encompassing two types of activity: evoked activity (phase-locked to the stimulus) and induced activity (non-phase-locked to the stimulus). Time-frequency analyses of extracellular potentials recorded from all layers and the surface of the auditory cortex of anesthetized guinea pigs of both sexes showed that ICMS during the processing of a transient acoustic stimulus differentially affected the evoked and induced response. Specifically, ICMS enhanced the long-latency-induced component, mimicking physiological gain increasing top-down feedback processes. Furthermore, the phase of the local field potential at the time of stimulation was predictive of the response amplitude for acoustic stimulation, ICMS, as well as combined acoustic and electric stimulation. Together, this was interpreted as a sign that the response to electrical stimulation was integrated into the ongoing cortical processes in contrast to substituting them. Consequently, ICMS modulated the cortical response to a sensory stimulus. We propose such targeted modulation of cortical activity (as opposed to a stimulation that substitutes the ongoing processes) as an alternative approach for cortical prostheses.SIGNIFICANCE STATEMENT Intracortical microstimulation (ICMS) is commonly used to activate a specific subset of cortical neurons, without taking into account the ongoing activity at the time of stimulation. Here, we found that a low-current ICMS pulse modulated the way the auditory cortex processed a peripheral stimulus, by supra-additively combining the response to the ICMS with the cortical processing of the peripheral stimulus. This artificial modulation mimicked natural modulations of response magnitude such as attention or expectation. In contrast to what was implied in earlier studies, this shows that the response to electrical stimulation is not substituting ongoing cortical activity but is integrated into the natural processes.
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