A scalable, highly-multiplexed delta-encoded digital feedback ECoG recording amplifier with common and differential-mode artifact suppression

Smith, William Anthony; Uehlin, John P.; Perlmutter, Steve I.; Rudell, Jacques C.; Sathe, Visvesh

doi:10.23919/vlsic.2017.8008470

Cited by 34 publications

(21 citation statements)

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“…A current buffer with high-voltage supply supported the insufficient voltage of the in-chip DAC to apply electrical stimulation in animal testing. The artifact-tolerant method to prevent DC offset from the electrode was required in real in vivo testing, where on-chip solutions were also provided by previous works [52], [53]. Without a designed on-chip, the DC blockage (high-pass filter with bias, corner frequency: 0.05 Hz) with passive element was added at the input stage of integrated system board to prevent the DC offset.…”

Section: Verification Of Epilepsy Suppression By Wpssocmentioning

confidence: 99%

A Programmable EEG Monitoring SoC with Optical and Electrical Stimulation for Epilepsy Control

et al. 2020

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In this paper, a cross-domain integration system composed of a gene transfer technique with a pre-clinical trial, an on-chip circuit design, an off-chip hardware with peripheral unit integration, and a custom software is presented. Opsin protein-gene transfer is successfully conducted to demonstrate that gene transfer treatment with optical stimulation has several benefits compared with electrical treatment. The proposed wireless programmable stimulating system on chip (WPSSoC) is composed of two sensing channels combined with a decimation filter to acquire intracranial electroencephalography (iEEG), an epilepsy detection unit (EDU), a stimulator with a waveform controller, and an ultra-low-power embedded transceiver. The equivalent sample rate of sensed data is 375 samples/s with 16-bit output data. The performance of intermodulation distortion with a third order (IMD 3) is approximately 68 dB. The EDU extracts approximate entropy (ApEn) and spectrum bins for the classifier. The stimulator with controller features on the waveform-adjustable function to provide 0-510 µA of electrical stimulation and 0-50 mW of optical stimulation. The proposed transceiver is implemented with a 2.45 GHz on-off keying (OOK) carrier frequency. Transmitter and receiver front-ends perform at 50.6 and 12.7 pJ/bit of energy per bit, respectively. Power consumption and area of WPSSoC are about 1 mW and 13.67 mm 2 in a 0.18 µm process, respectively. Circuits of each part are integrated in a 4.3 cm × 2 cm printed circuit board. The shrunk device is verified with Thy1-ChR2-YFP gene transfer in C57BL/6 mice by using a custom software which is used to provide commands and monitor iEEG. INDEX TERMS ChR2 gene transferring, electrical stimulation, epilepsy, implantable device, in vivo testing, open-/closed-loop control, optical stimulation, system-on-chip, wireless monitoring and control.

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Section: Verification Of Epilepsy Suppression By Wpssocmentioning

confidence: 99%

A Programmable EEG Monitoring SoC with Optical and Electrical Stimulation for Epilepsy Control

et al. 2020

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“…As a result, neural recording designs have primarily focused on optimizing power efficiency to extend battery life, reduce wireless power harvesting requirements, or minimize heat dissipation [28][29][30][31]. As recording systems scale to higher channel counts (>1000), power-efficient design is further exacerbated by tight area constraints [32][33][34] and high communication data rates [35].…”

Section: Design For Front-end Artifact Immunitymentioning

confidence: 99%

“…Another approach is to reduce the requirement for a large dynamic range by subtracting, using hardware methods, a model of the artifact at the input during stimulation to keep signals within a smaller range (Figure 3f). The model of the artifact is learned through template building [32,37], filtering the stimulation pulse [38 ], or creating a replica artifact signal [39]. This technique holds promise, but can degrade the signal-to-noise ratio (SNR) of the underlying neural signal [38 ].…”

Section: Design For Front-end Artifact Immunitymentioning

confidence: 99%

Toward true closed-loop neuromodulation: artifact-free recording during stimulation

Zhou

Johnson

Muller

2018

Current Opinion in Neurobiology

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Closed-loop and responsive neuromodulation systems improve open-loop neurostimulation by responding directly to measured neural activity and providing adaptive, on-demand therapy. To be effective, these systems must be able to simultaneously record and stimulate neural activity, a task made difficult by persistent stimulation artifacts that distort and obscure underlying biomarkers. To enable simultaneous stimulation and recording, several techniques have been proposed. These techniques involve artifact-preventing system configurations, resilient recording front-ends, and back-end signal processing for removing recorded artifacts. Co-designing and integrating these artifact cancellation techniques will be key to enabling neuromodulation systems to stimulate and record at the same time. Here, we review the state-of-the-art for these techniques and their role in achieving artifact-free neuromodulation.

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“…This led to the choice of implementing the 5-bit fine offset correction DAC by changing the size of the input pair [ 28 ], resulting in low area overhead and fast settling (<166 ns). An alternative would be a capacitive DAC at the G M input nodes [ 18 ], but this approach would require capacitive coupling between the LNA and G M amplifiers, and the input pair DAC is a simpler implementation.…”

Section: Rapidly Multiplexed Neural Recording Circuit Architecturementioning

confidence: 99%

“…However, rapid multiplexing directly at the electrodes raises challenges related to electrode offsets and aliasing of high-frequency noise. These challenges have been shown to be tractable for non-penetrating microelectrode arrays used in electrocorticography (ECoG) [ 18 , 19 ], but these low-impedance arrays measure average neural activity from large groups of neurons and generally do not provide the spatial or temporal resolution needed to observe action potentials.…”

Section: Introductionmentioning

confidence: 99%

Acquisition of Neural Action Potentials Using Rapid Multiplexing Directly at the Electrodes

et al. 2018

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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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A scalable, highly-multiplexed delta-encoded digital feedback ECoG recording amplifier with common and differential-mode artifact suppression

Cited by 34 publications

References 0 publications

A Programmable EEG Monitoring SoC with Optical and Electrical Stimulation for Epilepsy Control

A Programmable EEG Monitoring SoC with Optical and Electrical Stimulation for Epilepsy Control

Toward true closed-loop neuromodulation: artifact-free recording during stimulation

Acquisition of Neural Action Potentials Using Rapid Multiplexing Directly at the Electrodes

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