Signal and Noise Sources from Microwire Arrays Implanted in Rodent Cortex

Gardner, A. Tye; Walker, Ross M.; Strathman, Hunter J.; Warren, David J.

doi:10.1109/lsc.2018.8572180

Cited by 3 publications

(4 citation statements)

References 12 publications

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“…The variability in soak impedance is within the normal range observed in manufacturing. A mean increase of 26.34 ± 4.78 k (mean ± standard error) in impedance was observed following implantation, which is comparable to impedance shifts between saline and tissue recordings seen in prior studies for other clinical applications (Kane et al, 2013;Black et al, 2018;Gardner et al, 2018). There was no significant difference between the impedance's of electrodes grouped by shaft length (one-way ANOVA, p = 0.98).…”

Section: Electrophysiological Findingssupporting

confidence: 77%

Development of a feline model for preclinical research of a new translabyrinthine auditory nerve implant

Thomas,

Zuniga,

Sondh

et al. 2024

Front. Neurosci.

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Cochlear implants are among the most successful neural prosthetic devices to date but exhibit poor frequency selectivity and the inability to consistently activate apical (low frequency) spiral ganglion neurons. These issues can limit hearing performance in many cochlear implant patients, especially for understanding speech in noisy environments and in perceiving or appreciating more complex inputs such as music and multiple talkers. For cochlear implants, electrical current must pass through the bony wall of the cochlea, leading to widespread activation of auditory nerve fibers. Cochlear implants also cannot be implanted in some individuals with an obstruction or severe malformations of the cochlea. Alternatively, intraneural stimulation delivered via an auditory nerve implant could provide direct contact with neural fibers and thus reduce unwanted current spread. More confined current during stimulation can increase selectivity of frequency fiber activation. Furthermore, devices such as the Utah Slanted Electrode Array can provide access to the full cross section of the auditory nerve, including low frequency fibers that are difficult to reach using a cochlear implant. However, further scientific and preclinical research of these Utah Slanted Electrode Array devices is limited by the lack of a chronic large animal model for the auditory nerve implant, especially one that leverages an appropriate surgical approach relevant for human translation. This paper presents a newly developed transbullar translabyrinthine surgical approach for implanting the auditory nerve implant into the cat auditory nerve. In our first of a series of studies, we demonstrate a surgical approach in non-recovery experiments that enables implantation of the auditory nerve implant into the auditory nerve, without damaging the device and enabling effective activation of the auditory nerve fibers, as measured by electrode impedances and electrically evoked auditory brainstem responses. These positive results motivate performing future chronic cat studies to assess the long-term stability and function of these auditory nerve implant devices, as well as development of novel stimulation strategies that can be translated to human patients.

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Section: Electrophysiological Findingssupporting

confidence: 77%

Development of a feline model for preclinical research of a new translabyrinthine auditory nerve implant

Thomas,

Zuniga,

Sondh

et al. 2024

Front. Neurosci.

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“…Recently, we performed wideband spectral measurements of implanted electrodes [ 37 , 38 , 39 , 40 ] ( Figure 3 ). These measurements characterize the noise at high frequency as thermal in origin, on the basis of impedance magnitude and phase measurements.…”

Section: Rapidly Multiplexed Neural Recording: Theory and Practicamentioning

confidence: 99%

“…Background biological noise is generally in the 5–10 µV rms range in the AP band [ 17 ], which would correspond to 75–150 nV rms /

white noise across 0.5–5 kHz. Our studies [ 38 ] have also shown that high-frequency electromagnetic interference can be eliminated through proper referencing, grounding, and shielding, and that biological noise is confined to low frequencies (<10 kHz) [ 37 ]. Overall, thermal noise is the dominant concern at high frequencies and can be accurately predicted by impedance magnitude and phase measurements [ 38 ].…”

Section: Rapidly Multiplexed Neural Recording: Theory and Practicamentioning

confidence: 99%

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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 Multiplexed Electrochemical Measurement System for Characterization of Implanted Electrodes

Gardner

Strathman

Walker

2020

2020 IEEE International Symposium on Circuits and Systems (ISCAS)

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Signal and Noise Sources from Microwire Arrays Implanted in Rodent Cortex

Cited by 3 publications

References 12 publications

Development of a feline model for preclinical research of a new translabyrinthine auditory nerve implant

Development of a feline model for preclinical research of a new translabyrinthine auditory nerve implant

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

A Multiplexed Electrochemical Measurement System for Characterization of Implanted Electrodes

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