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Sharma K, Tripathi RK, Jatana HS, Sharma R. Design of a low-noise low-voltage amplifier for improved neural signal recording. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:064710. [PMID: 35777993 DOI: 10.1063/5.0087527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Design of amplifier circuits with low-noise operable at low-power to be used, especially for implantable neural interfaces, remains a huge challenge. This research paper presents the design of a low-noise low-voltage neural recording amplifier suitable for amplifying local field potentials and extracellular action potentials so as to meet the end requirement of an implantable neuro-medical system. Critical performance parameters of the smaller circuit blocks of the complete neural amplifier architecture have been found with the help of detailed mathematical analysis and then verified by the simulations conducted using 0.18 µm 4M1P foundry Semi-conductor Laboratory N-well process. The neural amplifier design proposed in this paper passes neural signal of interest with a mid-band gain of 49.9 dB over a bandwidth of 5.3 Hz-8.6 kHz, draws only 11.5 µW of power from ±0.9 V supply voltage, and exhibits an input-referred noise of 2.6 µVrms with a noise efficiency factor of 2.27. The area consumed by the proposed neural amplifier architecture is 0.192 mm2. The complete circuit design carried out in this paper should prove to be useful in equipment for the diagnosis of neurological disorders.
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Affiliation(s)
- Kulbhushan Sharma
- VLSI Centre of Excellence, Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India
| | | | - H S Jatana
- Semi-conductor Laboratory (SCL), Mohali, Punjab, India
| | - Rajnish Sharma
- VLSI Centre of Excellence, Chitkara University Institute of Engineering and Technology, Chitkara University, Punjab, India
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Kim JP, Lee W, Suh J, Lee H, Lee K, Ahn HY, Seo MJ, Ryu ST, Aristovich K, Holder D, Kim SJ. A 10 nV/rt Hz noise level 32-channel neural impedance sensing ASIC for local activation imaging on nerve section. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:4012-4015. [PMID: 33018879 DOI: 10.1109/embc44109.2020.9176708] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A 10 nV/rt Hz noise level 32-channel neural impedance sensing ASIC is presented for the application of local activation imaging in nerve section. It is increasingly known that the monitoring and control of nerve signals can improve physical and mental health. Major nerves, such as the vagus nerve and the sciatic nerve, consist of a bundle of fascicles. Therefore, to accurately control a particular application without any side effects, we need to know exactly which fascicle was activated. The only way to find locally activated fascicle is to use electrical impedance tomography (EIT). The ASIC to be introduced is designed for neural EIT applications. A neural impedance sensing ASIC was implemented using CMOS 180-nm process technology. The integrated input referred noise was calculated to be 0.46 μVrms (noise floor 10.3 nVrms/rt Hz) in the measured noise spectrum. At an input of 80 mV, the squared correlation coefficient for linear regression was 0.99998. The amplification gain uniformity of 32 channels was in the range of + 0.23% and - 0.29%. Using the resistor phantom, the simplest model of nerve, it was verified that a single readout channel could detect a signal-to- noise ratio of 75.6 dB or more. Through the reservoir phantom, real-time EIT images were reconstructed at a rate of 8.3 frames per second. The developed ASIC has been applied to in vivo experiments with rat sciatic nerves, and signal processing is currently underway to obtain activated nerve cross-sectional images. The developed ASIC was also applied to in-vivo experiments with rat sciatic nerves, and signal processing is currently underway to obtain locally activated nerve cross-sectional images.
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Sharma M, Strathman HJ, Walker RM. Verification of a Rapidly Multiplexed Circuit for Scalable Action Potential Recording. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2019; 13:1655-1663. [PMID: 31825873 PMCID: PMC7454001 DOI: 10.1109/tbcas.2019.2958348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
This report presents characterizations of in vivo neural recordings performed with a CMOS multichannel neural recording chip that uses rapid multiplexing directly at the electrodes, without any pre-amplification or buffering. Neural recordings were taken from a 16-channel microwire array implanted in rodent cortex, with comparison to a gold-standard commercial bench-top recording system. We were able to record well-isolated threshold crossings from 10 multiplexed electrodes and typical local field potential waveforms from 16, with strong agreement with the standard system (average SNR = 2.59 and 3.07 respectively). For 10 electrodes, the circuit achieves an effective area per channel of 0.0077 mm2, which is >5x smaller than typical multichannel chips. Extensive characterizations of noise and signal quality are presented and compared to fundamental theory, as well as results from in vivo and in vitro experiments. By demonstrating the validation of rapid multiplexing directly at the electrodes, this report confirms it as a promising approach for reducing circuit area in massively-multichannel neural recording systems, which is crucial for scaling recording site density and achieving large-scale sensing of brain activity with high spatiotemporal resolution.
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Putzeys J, Raducanu BC, Carton A, De Ceulaer J, Karsh B, Siegle JH, Van Helleputte N, Harris TD, Dutta B, Musa S, Mora Lopez C. Neuropixels Data-Acquisition System: A Scalable Platform for Parallel Recording of 10 000+ Electrophysiological Signals. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2019; 13:1635-1644. [PMID: 31545742 DOI: 10.1109/tbcas.2019.2943077] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Although CMOS fabrication has enabled a quick evolution in the design of high-density neural probes and neural-recording chips, the scaling and miniaturization of the complete data-acquisition systems has happened at a slower pace. This is mainly due to the complexity and the many requirements that change depending on the specific experimental settings. In essence, the fundamental challenge of a neural-recording system is getting the signals describing the largest possible set of neurons out of the brain and down to data storage for analysis. This requires a complete system optimization that considers the physical, electrical, thermal and signal-processing requirements, while accounting for available technology, manufacturing constraints and budget. Here we present a scalable and open-standards-based open-source data-acquisition system capable of recording from over 10,000 channels of raw neural data simultaneously. The components and their interfaces have been optimized to ensure robustness and minimum invasiveness in small-rodent electrophysiology.
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Tam WK, Wu T, Zhao Q, Keefer E, Yang Z. Human motor decoding from neural signals: a review. BMC Biomed Eng 2019; 1:22. [PMID: 32903354 PMCID: PMC7422484 DOI: 10.1186/s42490-019-0022-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 07/21/2019] [Indexed: 01/24/2023] Open
Abstract
Many people suffer from movement disability due to amputation or neurological diseases. Fortunately, with modern neurotechnology now it is possible to intercept motor control signals at various points along the neural transduction pathway and use that to drive external devices for communication or control. Here we will review the latest developments in human motor decoding. We reviewed the various strategies to decode motor intention from human and their respective advantages and challenges. Neural control signals can be intercepted at various points in the neural signal transduction pathway, including the brain (electroencephalography, electrocorticography, intracortical recordings), the nerves (peripheral nerve recordings) and the muscles (electromyography). We systematically discussed the sites of signal acquisition, available neural features, signal processing techniques and decoding algorithms in each of these potential interception points. Examples of applications and the current state-of-the-art performance were also reviewed. Although great strides have been made in human motor decoding, we are still far away from achieving naturalistic and dexterous control like our native limbs. Concerted efforts from material scientists, electrical engineers, and healthcare professionals are needed to further advance the field and make the technology widely available in clinical use.
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Affiliation(s)
- Wing-kin Tam
- Department of Biomedical Engineering, University of Minnesota Twin Cities, 7-105 Hasselmo Hall, 312 Church St. SE, Minnesota, 55455 USA
| | - Tong Wu
- Department of Biomedical Engineering, University of Minnesota Twin Cities, 7-105 Hasselmo Hall, 312 Church St. SE, Minnesota, 55455 USA
| | - Qi Zhao
- Department of Computer Science and Engineering, University of Minnesota Twin Cities, 4-192 Keller Hall, 200 Union Street SE, Minnesota, 55455 USA
| | - Edward Keefer
- Nerves Incorporated, Dallas, TX P. O. Box 141295 USA
| | - Zhi Yang
- Department of Biomedical Engineering, University of Minnesota Twin Cities, 7-105 Hasselmo Hall, 312 Church St. SE, Minnesota, 55455 USA
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Sharma K, Sharma R. Design considerations for effective neural signal sensing and amplification: a review. Biomed Phys Eng Express 2019. [DOI: 10.1088/2057-1976/ab1674] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Sharma M, Gardner AT, Strathman HJ, Warren DJ, Silver J, Walker RM. Acquisition of Neural Action Potentials Using Rapid Multiplexing Directly at the Electrodes. MICROMACHINES 2018; 9:E477. [PMID: 30424410 PMCID: PMC6215140 DOI: 10.3390/mi9100477] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 09/15/2018] [Accepted: 09/17/2018] [Indexed: 02/02/2023]
Abstract
Neural recording systems that interface with implanted microelectrodes are used extensively in experimental neuroscience and neural engineering research. Interface electronics that are needed to amplify, filter, and digitize signals from multichannel electrode arrays are a critical bottleneck to scaling such systems. This paper presents the design and testing of an electronic architecture for intracortical neural recording that drastically reduces the size per channel by rapidly multiplexing many electrodes to a single circuit. The architecture utilizes mixed-signal feedback to cancel electrode offsets, windowed integration sampling to reduce aliased high-frequency noise, and a successive approximation analog-to-digital converter with small capacitance and asynchronous control. Results are presented from a 180 nm CMOS integrated circuit prototype verified using in vivo experiments with a tungsten microwire array implanted in rodent cortex. The integrated circuit prototype achieves <0.004 mm² area per channel, 7 µW power dissipation per channel, 5.6 µVrms input referred noise, 50 dB common mode rejection ratio, and generates 9-bit samples at 30 kHz per channel by multiplexing at 600 kHz. General considerations are discussed for rapid time domain multiplexing of high-impedance microelectrodes. Overall, this work describes a promising path forward for scaling neural recording systems to numbers of electrodes that are orders of magnitude larger.
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Affiliation(s)
- Mohit Sharma
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112, USA.
| | - Avery Tye Gardner
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112, USA.
| | - Hunter J Strathman
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA.
| | - David J Warren
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA.
| | - Jason Silver
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112, USA.
| | - Ross M Walker
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112, USA.
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Huang YC, Huang PT, Wu SL, Hu YC, You YH, Chen JM, Huang YY, Chang HC, Lin YH, Duann JR, Chiu TW, Hwang W, Chen KN, Chuang CT, Chiou JC. Ultrahigh-Density 256-Channel Neural Sensing Microsystem Using TSV-Embedded Neural Probes. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2017; 11:1013-1025. [PMID: 28371785 DOI: 10.1109/tbcas.2017.2669439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Highly integrated neural sensing microsystems are crucial to capture accurate signals for brain function investigations. In this paper, a 256-channel neural sensing microsystem with a sensing area of 5 × 5 mm 2 is presented based on 2.5-D through-silicon-via (TSV) integration. This microsystem composes of dissolvable μ-needles, TSV-embedded μ-probes, 256-channel neural amplifiers, 11-bit area-power-efficient successive approximation register analog-to-digital converters, and serializers. This microsystem can detect 256 electrocorticography and local field potential signals within a small area of 5 mm × 5 mm. The neural amplifier realizes 57.8 dB gain with only 9.8 μW per channel. The overall power of this microsystem is only 3.79 mW for 256-channel neural sensing. A smaller microsystem with dimension of 6 mm × 4 mm has been also implanted into rat brain for somatosensory evoked potentials (SSEPs) recording by using contralateral and ipsilateral electrical stimuli with intensity from 0.2 to 1.0 mA, and successfully observed different SSEPs from left somatosensory cortex of a rat.
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Affiliation(s)
- Yu-Chieh Huang
- Institute of Electrical Control Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Po-Tsang Huang
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Shang-Lin Wu
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Yu-Chen Hu
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Yan-Huei You
- Institute of Electrical Control Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Jr-Ming Chen
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Yan-Yu Huang
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Hsiao-Chun Chang
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Yen-Han Lin
- Institute of Electrical Control Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Jeng-Ren Duann
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan, R.O.C
| | - Tzai-Wen Chiu
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Wei Hwang
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Kuan-Neng Chen
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Ching-Te Chuang
- Department of Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
| | - Jin-Chern Chiou
- Institute of Electrical Control Engineering and the Department of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, Taiwan, R.O.C
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