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McNamara IN, Wellman SM, Li L, Eles JR, Savya S, Sohal HS, Angle MR, Kozai TDY. Electrode sharpness and insertion speed reduce tissue damage near high-density penetrating arrays. J Neural Eng 2024; 21:026030. [PMID: 38518365 DOI: 10.1088/1741-2552/ad36e1] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/22/2024] [Indexed: 03/24/2024]
Abstract
Objective. Over the past decade, neural electrodes have played a crucial role in bridging biological tissues with electronic and robotic devices. This study focuses on evaluating the optimal tip profile and insertion speed for effectively implanting Paradromics' high-density fine microwire arrays (FμA) prototypes into the primary visual cortex (V1) of mice and rats, addressing the challenges associated with the 'bed-of-nails' effect and tissue dimpling.Approach. Tissue response was assessed by investigating the impact of electrodes on the blood-brain barrier (BBB) and cellular damage, with a specific emphasis on tailored insertion strategies to minimize tissue disruption during electrode implantation.Main results.Electro-sharpened arrays demonstrated a marked reduction in cellular damage within 50μm of the electrode tip compared to blunt and angled arrays. Histological analysis revealed that slow insertion speeds led to greater BBB compromise than fast and pneumatic methods. Successful single-unit recordings validated the efficacy of the optimized electro-sharpened arrays in capturing neural activity.Significance.These findings underscore the critical role of tailored insertion strategies in minimizing tissue damage during electrode implantation, highlighting the suitability of electro-sharpened arrays for long-term implant applications. This research contributes to a deeper understanding of the complexities associated with high-channel-count microelectrode array implantation, emphasizing the importance of meticulous assessment and optimization of key parameters for effective integration and minimal tissue disruption. By elucidating the interplay between insertion parameters and tissue response, our study lays a strong foundation for the development of advanced implantable devices with a reduction in reactive gliosis and improved performance in neural recording applications.
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Affiliation(s)
- Ingrid N McNamara
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Steven M Wellman
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Lehong Li
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - James R Eles
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Sajishnu Savya
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | | | | | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center of the Basis of Neural Cognition, Pittsburgh, PA, United States of America
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
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Boergens KM, Tadić A, Hopper MS, McNamara I, Fell D, Sahasrabuddhe K, Kong Y, Straka M, Sohal HS, Angle MR. Laser ablation of the pia mater for insertion of high-density microelectrode arrays in a translational sheep model. J Neural Eng 2021; 18. [PMID: 34038875 DOI: 10.1088/1741-2552/ac0585] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 09/20/2020] [Accepted: 05/26/2021] [Indexed: 01/03/2023]
Abstract
Objective. The safe insertion of high density intracortical electrode arrays has been a long-standing practical challenge for neural interface engineering and applications such as brain-computer interfaces (BCIs). However, the pia mater can be difficult to penetrate and causes deformation of underlying cortical tissue during insertion of high-density intracortical arrays. This can lead to neuron damage or failed insertions. The development of a method to ease insertion through the pia mater would represent a significant step toward inserting high density intracortical arrays.Approach. Here we describe a surgical procedure, inspired by laser corneal ablation, that can be used in translational models to thin the pia mater.Main results. We demonstrate that controlled pia removal with laser ablation over a small area of cortex allows for microelectrode arrays to be inserted into the cortex with less force, thus reducing deformation of underlying tissue during placement of the microelectrodes. This procedure allows for insertion of high-density electrode arrays and subsequent acute recordings of spiking neuron activity in sheep cortex. We also show histological and electrophysiological evidence that laser removal of the pia does not acutely affect neuronal viability in the region.Significance. Laser ablation of the pia reduces insertion forces of high-density arrays with minimal to no acute damage to cortical neurons. This approach suggests a promising new path for clinical BCI with high-density microelectrode arrays.
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Affiliation(s)
| | | | | | | | - Devin Fell
- Paradromics, Inc., Austin, TX, United States of America
| | | | - Yifan Kong
- Paradromics, Inc., Austin, TX, United States of America
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Sahasrabuddhe K, Khan AA, Singh AP, Stern TM, Ng Y, Tadić A, Orel P, LaReau C, Pouzzner D, Nishimura K, Boergens KM, Shivakumar S, Hopper MS, Kerr B, Hanna MES, Edgington RJ, McNamara I, Fell D, Gao P, Babaie-Fishani A, Veijalainen S, Klekachev AV, Stuckey AM, Luyssaert B, Kozai TDY, Xie C, Gilja V, Dierickx B, Kong Y, Straka M, Sohal HS, Angle MR. The Argo: a high channel count recording system for neural recording in vivo. J Neural Eng 2021; 18:015002. [PMID: 33624614 PMCID: PMC8607496 DOI: 10.1088/1741-2552/abd0ce] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Decoding neural activity has been limited by the lack of tools available to record from large numbers of neurons across multiple cortical regions simultaneously with high temporal fidelity. To this end, we developed the Argo system to record cortical neural activity at high data rates. APPROACH Here we demonstrate a massively parallel neural recording system based on platinum-iridium microwire electrode arrays bonded to a CMOS voltage amplifier array. The Argo system is the highest channel count in vivo neural recording system, supporting simultaneous recording from 65 536 channels, sampled at 32 kHz and 12-bit resolution. This system was designed for cortical recordings, compatible with both penetrating and surface microelectrodes. MAIN RESULTS We validated this system through initial bench testing to determine specific gain and noise characteristics of bonded microwires, followed by in-vivo experiments in both rat and sheep cortex. We recorded spiking activity from 791 neurons in rats and surface local field potential activity from over 30 000 channels in sheep. SIGNIFICANCE These are the largest channel count microwire-based recordings in both rat and sheep. While currently adapted for head-fixed recording, the microwire-CMOS architecture is well suited for clinical translation. Thus, this demonstration helps pave the way for a future high data rate intracortical implant.
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Affiliation(s)
| | - Aamir A Khan
- Paradromics, Inc, Austin, TX, United States of America
| | | | - Tyler M Stern
- Paradromics, Inc, Austin, TX, United States of America
| | - Yeena Ng
- Paradromics, Inc, Austin, TX, United States of America
| | | | - Peter Orel
- Paradromics, Inc, Austin, TX, United States of America
| | - Chris LaReau
- Paradromics, Inc, Austin, TX, United States of America
| | | | | | | | | | | | - Bryan Kerr
- Paradromics, Inc, Austin, TX, United States of America
| | | | | | | | - Devin Fell
- Paradromics, Inc, Austin, TX, United States of America
| | - Peng Gao
- Caeleste CVBA, Mechelen, Belgium
| | | | | | | | | | | | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States of America
- McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States of America
- NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, United States of America
| | - Chong Xie
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, United States of America
- Department of Bioengineering, Rice University, Houston, TX, United States of America
- NeuroEngineering Initiative, Rice University, Houston, TX, United States of America
| | - Vikash Gilja
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, United States of America
| | | | - Yifan Kong
- Paradromics, Inc, Austin, TX, United States of America
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Falcone JD, Liu T, Goldman L, David D P, Rieth L, Bouton CE, Straka M, Sohal HS. A novel microwire interface for small diameter peripheral nerves in a chronic, awake murine model. J Neural Eng 2020; 17:046003. [DOI: 10.1088/1741-2552/ab9b6d] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Falcone JD, Sohal HS, Kyriakides TR, Bellamkonda RV. The impact of modulating the blood-brain barrier on the electrophysiological and histological outcomes of intracortical electrodes. J Neural Eng 2019; 16:046005. [PMID: 31048574 DOI: 10.1088/1741-2552/ab1ef9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Successful application of chronic intracortical electrodes remains highly variable. The biological mechanisms leading to electrode failure are still being explored. Recent work has shown a correlation between blood-brain barrier (BBB) integrity and long-term recordings. Here we proposed to modulate the BBB healing after intracortical electrode implantation, while evaluating the functional electrophysiology. The CCL2/CCR2 pathway was chosen based on previous work demonstrating the positive histological effects in an intracortical electrode model, as well as in other neurodegenerative models. By disrupting this pathway, recruitment of pro-inflammatory monocytes (a result of a breached BBB) is potentially reduced at the electrode interface. APPROACH Michigan electrodes were implanted for 2 and 12 weeks in rats, and a CCR2 antagonist (RS 102895) was administered daily to the treatment group. Functional electrodes were used for the 12 week cohort, and weekly electrophysiological recordings were taken. At 2 and 12 weeks, histology was analyzed. MAIN RESULTS At 12 weeks, the CCR2-antagonist group had significantly higher signal-to-noise ratios (SNRs) than control. CCR2-antagonism at 2 weeks significantly increased the neural population and decreased BBB breach. At 12 weeks, CCR2-antagonism significantly increased number of neurons and BBB + vasculature within 100 µm of the electrode interface. SIGNIFICANCE This work demonstrates that for intracortical electrodes, disruption of the CCL2/CCR2 pathway improves chronic outcomes in electrophysiology and histology.
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Affiliation(s)
- Jessica D Falcone
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, United States of America
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Garg Y, Singh J, Sohal HS, Gore R, Kumar A. Comparison of Clinical Effectiveness and Safety of Newer Nonsteroidal Anti-inflammatory Drugs in Patients of Osteoarthritis of Knee Joint: A Randomized, Prospective, Open-label Parallel-group Study. Indian J Pharmacol 2018. [PMID: 29515279 PMCID: PMC5830849 DOI: 10.4103/ijp.ijp_245_16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE: Osteoarthritis (OA) is a chronic progressive degenerative disease of weight-bearing joints and the leading cause of disability in elderly. Current medical management of OA is mostly palliative with nonsteroidal anti-inflammatory drugs (NSAIDs) being the mainstay of therapy. Reports of gastrointestinal adverse effects with traditional NSAIDs and cardiovascular adverse effects associated with selective cyclooxygenase-2 (COX-2) inhibitors have prompted the hunt for a better NSAID with no or minimal adverse effects. This study compares the clinical effectiveness and safety of newer NSAIDS etodolac and lornoxicam to diclofenac which has been a standard therapy in patients of OA of knee joint. MATERIALS AND METHODS: It was a randomized, prospective, open-label, parallel-group study conducted in 90 patients of OA of knee joint diagnosed according to the American College of Rheumatology criteria. After obtaining the informed consent, they were randomized in three groups of 30 patients each who received tablet etodolac 400 mg b.i.d, tablet lornoxicam 8 mg b.i.d, and tablet diclofenac sodium 50 mg t.i.d, respectively. The duration of the study was 12 weeks. Data were tabulated and analyzed using analysis of variance (ANOVA) test, and level of significance was determined by its P value. RESULTS: After 12 weeks of treatment, pain intensity and functional indices in terms of visual analog scale and Western Ontario and McMaster Universities Osteoarthritis score were significantly better (P < 0.05) in lornoxicam group as compared to etodolac or diclofenac group along with lesser rate of adverse effects. CONCLUSION: It was concluded that lornoxicam was more effective and better tolerated NSAID than etodolac and diclofenac in treatment of knee joint OA.
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Affiliation(s)
- Yashika Garg
- Department of Pharmacology, Government Medical College and Hospital, Amritsar, Punjab, India.,Department of Pharmacology, Vardhman Mahavir Medical College and Safdarjung Hospital, Rohini, New Delhi, India.,Department of Pharmacology, ESIC Dental College and Hospital, Rohini, New Delhi, India
| | - Jatinder Singh
- Department of Pharmacology, Government Medical College and Hospital, Amritsar, Punjab, India
| | - H S Sohal
- Department of Orthopaedics, Government Medical College and Hospital, Amritsar, Punjab, India
| | - Rajeshwari Gore
- Department of Pharmacology, Vardhman Mahavir Medical College and Safdarjung Hospital, Rohini, New Delhi, India
| | - Arun Kumar
- Department of Pharmacology, Vardhman Mahavir Medical College and Safdarjung Hospital, Rohini, New Delhi, India
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Caravaca AS, Tsaava T, Goldman L, Silverman H, Riggott G, Chavan SS, Bouton C, Tracey KJ, Desimone R, Boyden ES, Sohal HS, Olofsson PS. A novel flexible cuff-like microelectrode for dual purpose, acute and chronic electrical interfacing with the mouse cervical vagus nerve. J Neural Eng 2017; 14:066005. [PMID: 28628030 PMCID: PMC6130808 DOI: 10.1088/1741-2552/aa7a42] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Neural reflexes regulate immune responses and homeostasis. Advances in bioelectronic medicine indicate that electrical stimulation of the vagus nerve can be used to treat inflammatory disease, yet the understanding of neural signals that regulate inflammation is incomplete. Current interfaces with the vagus nerve do not permit effective chronic stimulation or recording in mouse models, which is vital to studying the molecular and neurophysiological mechanisms that control inflammation homeostasis in health and disease. We developed an implantable, dual purpose, multi-channel, flexible 'microelectrode' array, for recording and stimulation of the mouse vagus nerve. APPROACH The array was microfabricated on an 8 µm layer of highly biocompatible parylene configured with 16 sites. The microelectrode was evaluated by studying the recording and stimulation performance. Mice were chronically implanted with devices for up to 12 weeks. MAIN RESULTS Using the microelectrode in vivo, high fidelity signals were recorded during physiological challenges (e.g potassium chloride and interleukin-1β), and electrical stimulation of the vagus nerve produced the expected significant reduction of blood levels of tumor necrosis factor (TNF) in endotoxemia. Inflammatory cell infiltration at the microelectrode 12 weeks of implantation was limited according to radial distribution analysis of inflammatory cells. SIGNIFICANCE This novel device provides an important step towards a viable chronic interface for cervical vagus nerve stimulation and recording in mice.
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Affiliation(s)
- A S Caravaca
- Department of Medicine, Solna, Karolinska Institutet, Center for Molecular Medicine, Center for Bioelectronic Medicine, Karolinska University Hospital, Stockholm, Solna, Sweden
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Banal J, Sohal HS, Sharma R, Dhake J, Singh G. Autologous (Non vascularized) fibular grafting with cancellous bone grafting for treatment of femoral head osteonecrosis (Ficat and Arlet stage 1 2a 2b 3). ACTA ACUST UNITED AC 2017. [DOI: 10.22271/ortho.2017.v3.i1c.24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Sohal HS, Clowry GJ, Jackson A, O’Neill A, Baker SN. Mechanical Flexibility Reduces the Foreign Body Response to Long-Term Implanted Microelectrodes in Rabbit Cortex. PLoS One 2016; 11:e0165606. [PMID: 27788240 PMCID: PMC5082854 DOI: 10.1371/journal.pone.0165606] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 10/15/2016] [Indexed: 02/04/2023] Open
Abstract
Micromotion between the brain and implanted electrodes is a major contributor to the failure of invasive microelectrodes. Movements of the electrode tip cause recording instabilities while spike amplitudes decline over the weeks/months post-implantation due to glial cell activation caused by sustained mechanical trauma. We compared the glial response over a 26-96 week period following implantation in the rabbit cortex of microwires and a novel flexible electrode. Horizontal sections were used to obtain a depth profile of the radial distribution of microglia, astrocytes and neurofilament. We found that the flexible electrode was associated with decreased gliosis compared to the microwires over these long indwelling periods. This was in part due to a decrease in overall microgliosis and enhanced neuronal density around the flexible probe, especially at longer periods of implantation.
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Affiliation(s)
- Harbaljit S. Sohal
- Center for Bioelectronic Medicine, Feinstein Institute for Medical Research, Manhassett, NY, 11030, United States of America
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, NE2 4HH, United Kingdom
| | - Gavin J. Clowry
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, NE2 4HH, United Kingdom
| | - Andrew Jackson
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, NE2 4HH, United Kingdom
| | - Anthony O’Neill
- School of Electrical and Electronic Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, United Kingdom
| | - Stuart N. Baker
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, NE2 4HH, United Kingdom
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Sohal HS, Jackson A, Jackson R, Clowry GJ, Vassilevski K, O'Neill A, Baker SN. The sinusoidal probe: a new approach to improve electrode longevity. Front Neuroeng 2014; 7:10. [PMID: 24808859 PMCID: PMC4010751 DOI: 10.3389/fneng.2014.00010] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 04/07/2014] [Indexed: 11/13/2022]
Abstract
Micromotion between the brain and implanted electrodes is a major contributor to the failure of invasive brain-machine interfaces. Movements of the electrode tip cause recording instabilities while spike amplitudes decline over the weeks/months post-implantation due to glial cell activation caused by sustained mechanical trauma. We have designed a sinusoidal probe in order to reduce movement of the recording tip relative to the surrounding neural tissue. The probe was microfabricated from flexible materials and incorporated a sinusoidal shaft to minimize tethering forces and a 3D spheroid tip to anchor the recording site within the brain. Compared to standard microwire electrodes, the signal-to-noise ratio and local field potential power of sinusoidal probe recordings from rabbits was more stable across recording periods up to 678 days. Histological quantification of microglia and astrocytes showed reduced neuronal tissue damage especially for the tip region between 6 and 24 months post-implantation. We suggest that the micromotion-reducing measures incorporated into our design, at least partially, decreased the magnitude of gliosis, resulting in enhanced longevity of recording.
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Affiliation(s)
- Harbaljit S Sohal
- Newcastle Movement Lab, Institute of Neuroscience, Newcastle University Newcastle Upon Tyne, UK ; School of Electrical and Electronic Engineering, Newcastle University Newcastle Upon Tyne, UK
| | - Andrew Jackson
- Newcastle Movement Lab, Institute of Neuroscience, Newcastle University Newcastle Upon Tyne, UK
| | - Richard Jackson
- School of Electrical and Electronic Engineering, Newcastle University Newcastle Upon Tyne, UK
| | - Gavin J Clowry
- Newcastle Movement Lab, Institute of Neuroscience, Newcastle University Newcastle Upon Tyne, UK
| | - Konstantin Vassilevski
- School of Electrical and Electronic Engineering, Newcastle University Newcastle Upon Tyne, UK
| | - Anthony O'Neill
- School of Electrical and Electronic Engineering, Newcastle University Newcastle Upon Tyne, UK
| | - Stuart N Baker
- Newcastle Movement Lab, Institute of Neuroscience, Newcastle University Newcastle Upon Tyne, UK
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Narain D, Sohal HS. The sex chromatin in the pyramidal neurons of the camel Canelus dromedarius. Indian J Med Res 1968; 56:722-5. [PMID: 5748810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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