An Active Microchannel Neural Interface for Implantable Electrical Stimulation and Recording.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Electrical Engineering

Background:

• Peripheral nerve interfaces are crucial for neuroprosthetics and neuromodulation.
• Existing interfaces often lack selectivity, concurrent control, and miniaturization for long-term implantation.

Purpose of the Study:

• To present a mm-sized, implantable neural interface for bidirectional peripheral nerve control.
• To demonstrate highly selective, concurrent control of nerve sections using microchannel electrodes and an ASIC.

Main Methods:

• Developed a 0.18 μm CMOS application-specific integrated circuit (ASIC) for neural interfacing.
• Integrated high-voltage stimulation (45 V) and low-voltage recording (1.8 V) with microchannel electrodes.
• Utilized biphasic stimulus pulses and measured action potentials across a 10 kHz bandwidth with a low-noise amplifier.

Main Results:

• Achieved selective, concurrent control of 300-μm nerve sections.
• Stimulation parameters: up to 124 μA, 2 μA resolution, 7.4 Hz-20 kHz frequency.
• Recording parameters: 10 kHz bandwidth, up to 72 dB gain, 2.74 μVrms input-referred noise.
• Demonstrated artifact reduction and 1-ms amplifier recovery time.
• Validated in-vitro feasibility for closed-loop control and ex-vivo concurrent stimulation/recording.

Conclusions:

• The presented neural interface enables precise, bidirectional control of peripheral nerves.
• The ASIC design is suitable for miniaturized, implantable systems for neuromodulation and neuroprosthetics.
• The technology shows promise for advanced closed-loop neural control applications.