Harvey Wiggins - Academia.edu (original) (raw)

Papers by Harvey Wiggins

Research paper thumbnail of Cuff electrodes for very small diameter nerves — Prototyping and first recordings in vivo

A fabrication method for cuff electrodes to interface small nerves was developed. Medical grade s... more A fabrication method for cuff electrodes to interface small nerves was developed. Medical grade silicone rubber conforms the body of the cuff and insulation of the wires, platinum was used as metal for the embedded wiring and contacts. Planar electrode arrays where fabricated using a picosecond laser and then positioned into a carrying tube to provide the third dimension with the desired inner diameter (Ø 0.3-0.5 mm). The post preparation of the cuffs after structuring allows the fabrication of a stable self-closing flap that insulates the opening slit of the cuff without the need of extra sutures. Basic for the success of the cuff is the laser-based local thinning of both the silicone rubber and the metal at defined sections. This is critical to permit the PDMS' body to dominate the mechanical properties. Finite element modeling was applied to optimize the displacement ability of the cuff, leading to design capable of withstanding multiple implantation procedures without wire damage. Furthermore, the contact's surface was roughened by laser patterning to increase the charge injection capacity of Pt to 285 μC/cm(2) measured by voltage transient detection during pulse testing. The cuff electrodes were placed on a small sympathetic nerve of an adult female Sprague-Dawley rat for recording of spontaneous and evoked neural activity in vivo.

Research paper thumbnail of A Low-Noise, Wireless, Frequency-Shaping Neural Recorder

IEEE Journal on Emerging and Selected Topics in Circuits and Systems, Jun 1, 2018

This paper presents a low-noise, wireless neural recorder that has a frequency dependent amplific... more This paper presents a low-noise, wireless neural recorder that has a frequency dependent amplification to remove electrode offset and attenuate motion artifacts. The recorder has 2.5 GΩ and 50 MΩ input impedance at 20 Hz and 1 kHz for recording local field potentials and extracellular spikes, respectively. To reduce the input-referred noise, we propose a low-noise frontend design with multiple novel noise suppression techniques. To reduce the power consumption, we have integrated an EC-PC spike processor that automatically adjusts the recording bandwidth based on the signal contents. In bench-top measurement, the proposed neural recorder has 2.2 µV input-referred noise integrated from 300 Hz to 8 kHz and consumes 98 µW maximum power. In animal experiments, the output data of the neural signal processor are serialized and connected to a customized WiFi data link with up to 10 Mbps data rate. Through in-vivo experiments, we find the noise generated by the WiFi doesn't prevent brain recordings with microelectrodes and a clear interpretation of the neural signals; however, the noise can mask the weaker neural signals in nerve recordings with epineural electrodes.

Research paper thumbnail of Multiple unit action potential sorting: investigation of features, algorithms, and parameters for a fully automated system

Proceedings of the 15th Annual International Conference of the IEEE Engineering in Medicine and Biology Societ

ABSTRACT

Research paper thumbnail of The use of a novel carbon nanotube coated microelectrode array for chronic intracortical recording and microstimulation

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2012

Micro-electrode arrays (MEAs) have been used in a variety of intracortical neural prostheses. Whi... more Micro-electrode arrays (MEAs) have been used in a variety of intracortical neural prostheses. While intracortical MEAs have demonstrated their utility in neural prostheses, in many cases MEA performance declines after several months to years of in vivo implantation. The application of carbon nanotubes (CNTs) may increase the functional longevity of intracortical MEAs through enhanced biocompatibility and charge injection properties. An MEA metalized with platinum (Pt) on all electrodes had a CNT coating applied to the electrodes on half of the array. This Pt/Pt-CNT MEA was implanted into feline motor cortex for >1 year. Recordings of action potentials and 1 kHz impedance measurements were made on all electrodes to evaluate device functionality. Additionally, electromyogram (EMG) responses were evoked using micro-stimulation via the MEA to measure device performance. These metrics were compared between Pt and Pt-CNT electrodes. There was no significant difference in the data acqui...

Research paper thumbnail of Cuff electrodes for very small diameter nerves - Prototyping and first recordings in vivo

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2014

A fabrication method for cuff electrodes to interface small nerves was developed. Medical grade s... more A fabrication method for cuff electrodes to interface small nerves was developed. Medical grade silicone rubber conforms the body of the cuff and insulation of the wires, platinum was used as metal for the embedded wiring and contacts. Planar electrode arrays where fabricated using a picosecond laser and then positioned into a carrying tube to provide the third dimension with the desired inner diameter (Ø 0.3-0.5 mm). The post preparation of the cuffs after structuring allows the fabrication of a stable self-closing flap that insulates the opening slit of the cuff without the need of extra sutures. Basic for the success of the cuff is the laser-based local thinning of both the silicone rubber and the metal at defined sections. This is critical to permit the PDMS' body to dominate the mechanical properties. Finite element modeling was applied to optimize the displacement ability of the cuff, leading to design capable of withstanding multiple implantation procedures without wire d...

Research paper thumbnail of A Low-Noise, Wireless, Frequency-Shaping Neural Recorder

IEEE Journal on Emerging and Selected Topics in Circuits and Systems, 2018

This paper presents a low-noise, wireless neural recorder that has a frequency dependent amplific... more This paper presents a low-noise, wireless neural recorder that has a frequency dependent amplification to remove electrode offset and attenuate motion artifacts. The recorder has 2.5 GΩ and 50 MΩ input impedance at 20 Hz and 1 kHz for recording local field potentials and extracellular spikes, respectively. To reduce the input-referred noise, we propose a low-noise frontend design with multiple novel noise suppression techniques. To reduce the power consumption, we have integrated an EC-PC spike processor that automatically adjusts the recording bandwidth based on the signal contents. In bench-top measurement, the proposed neural recorder has 2.2 µV input-referred noise integrated from 300 Hz to 8 kHz and consumes 98 µW maximum power. In animal experiments, the output data of the neural signal processor are serialized and connected to a customized WiFi data link with up to 10 Mbps data rate. Through in-vivo experiments, we find the noise generated by the WiFi doesn't prevent brain recordings with microelectrodes and a clear interpretation of the neural signals; however, the noise can mask the weaker neural signals in nerve recordings with epineural electrodes.

Research paper thumbnail of Cuff electrodes for very small diameter nerves — Prototyping and first recordings in vivo

A fabrication method for cuff electrodes to interface small nerves was developed. Medical grade s... more A fabrication method for cuff electrodes to interface small nerves was developed. Medical grade silicone rubber conforms the body of the cuff and insulation of the wires, platinum was used as metal for the embedded wiring and contacts. Planar electrode arrays where fabricated using a picosecond laser and then positioned into a carrying tube to provide the third dimension with the desired inner diameter (Ø 0.3-0.5 mm). The post preparation of the cuffs after structuring allows the fabrication of a stable self-closing flap that insulates the opening slit of the cuff without the need of extra sutures. Basic for the success of the cuff is the laser-based local thinning of both the silicone rubber and the metal at defined sections. This is critical to permit the PDMS' body to dominate the mechanical properties. Finite element modeling was applied to optimize the displacement ability of the cuff, leading to design capable of withstanding multiple implantation procedures without wire damage. Furthermore, the contact's surface was roughened by laser patterning to increase the charge injection capacity of Pt to 285 μC/cm(2) measured by voltage transient detection during pulse testing. The cuff electrodes were placed on a small sympathetic nerve of an adult female Sprague-Dawley rat for recording of spontaneous and evoked neural activity in vivo.

Research paper thumbnail of A Low-Noise, Wireless, Frequency-Shaping Neural Recorder

IEEE Journal on Emerging and Selected Topics in Circuits and Systems, Jun 1, 2018

This paper presents a low-noise, wireless neural recorder that has a frequency dependent amplific... more This paper presents a low-noise, wireless neural recorder that has a frequency dependent amplification to remove electrode offset and attenuate motion artifacts. The recorder has 2.5 GΩ and 50 MΩ input impedance at 20 Hz and 1 kHz for recording local field potentials and extracellular spikes, respectively. To reduce the input-referred noise, we propose a low-noise frontend design with multiple novel noise suppression techniques. To reduce the power consumption, we have integrated an EC-PC spike processor that automatically adjusts the recording bandwidth based on the signal contents. In bench-top measurement, the proposed neural recorder has 2.2 µV input-referred noise integrated from 300 Hz to 8 kHz and consumes 98 µW maximum power. In animal experiments, the output data of the neural signal processor are serialized and connected to a customized WiFi data link with up to 10 Mbps data rate. Through in-vivo experiments, we find the noise generated by the WiFi doesn't prevent brain recordings with microelectrodes and a clear interpretation of the neural signals; however, the noise can mask the weaker neural signals in nerve recordings with epineural electrodes.

Research paper thumbnail of Multiple unit action potential sorting: investigation of features, algorithms, and parameters for a fully automated system

Proceedings of the 15th Annual International Conference of the IEEE Engineering in Medicine and Biology Societ

ABSTRACT

Research paper thumbnail of The use of a novel carbon nanotube coated microelectrode array for chronic intracortical recording and microstimulation

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2012

Micro-electrode arrays (MEAs) have been used in a variety of intracortical neural prostheses. Whi... more Micro-electrode arrays (MEAs) have been used in a variety of intracortical neural prostheses. While intracortical MEAs have demonstrated their utility in neural prostheses, in many cases MEA performance declines after several months to years of in vivo implantation. The application of carbon nanotubes (CNTs) may increase the functional longevity of intracortical MEAs through enhanced biocompatibility and charge injection properties. An MEA metalized with platinum (Pt) on all electrodes had a CNT coating applied to the electrodes on half of the array. This Pt/Pt-CNT MEA was implanted into feline motor cortex for >1 year. Recordings of action potentials and 1 kHz impedance measurements were made on all electrodes to evaluate device functionality. Additionally, electromyogram (EMG) responses were evoked using micro-stimulation via the MEA to measure device performance. These metrics were compared between Pt and Pt-CNT electrodes. There was no significant difference in the data acqui...

Research paper thumbnail of Cuff electrodes for very small diameter nerves - Prototyping and first recordings in vivo

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2014

A fabrication method for cuff electrodes to interface small nerves was developed. Medical grade s... more A fabrication method for cuff electrodes to interface small nerves was developed. Medical grade silicone rubber conforms the body of the cuff and insulation of the wires, platinum was used as metal for the embedded wiring and contacts. Planar electrode arrays where fabricated using a picosecond laser and then positioned into a carrying tube to provide the third dimension with the desired inner diameter (Ø 0.3-0.5 mm). The post preparation of the cuffs after structuring allows the fabrication of a stable self-closing flap that insulates the opening slit of the cuff without the need of extra sutures. Basic for the success of the cuff is the laser-based local thinning of both the silicone rubber and the metal at defined sections. This is critical to permit the PDMS' body to dominate the mechanical properties. Finite element modeling was applied to optimize the displacement ability of the cuff, leading to design capable of withstanding multiple implantation procedures without wire d...

Research paper thumbnail of A Low-Noise, Wireless, Frequency-Shaping Neural Recorder

IEEE Journal on Emerging and Selected Topics in Circuits and Systems, 2018

This paper presents a low-noise, wireless neural recorder that has a frequency dependent amplific... more This paper presents a low-noise, wireless neural recorder that has a frequency dependent amplification to remove electrode offset and attenuate motion artifacts. The recorder has 2.5 GΩ and 50 MΩ input impedance at 20 Hz and 1 kHz for recording local field potentials and extracellular spikes, respectively. To reduce the input-referred noise, we propose a low-noise frontend design with multiple novel noise suppression techniques. To reduce the power consumption, we have integrated an EC-PC spike processor that automatically adjusts the recording bandwidth based on the signal contents. In bench-top measurement, the proposed neural recorder has 2.2 µV input-referred noise integrated from 300 Hz to 8 kHz and consumes 98 µW maximum power. In animal experiments, the output data of the neural signal processor are serialized and connected to a customized WiFi data link with up to 10 Mbps data rate. Through in-vivo experiments, we find the noise generated by the WiFi doesn't prevent brain recordings with microelectrodes and a clear interpretation of the neural signals; however, the noise can mask the weaker neural signals in nerve recordings with epineural electrodes.