On-Probe Neural Interface ASIC for Combined Electrical Recording and Optogenetic Stimulation

Area of Science:

• Neuroscience
• Biomedical Engineering
• Electrical Engineering

Background:

• Neuromodulation is advancing towards closed-loop control systems.
• Optogenetics allows genetic modification for light-sensitive neural tissue, enabling simultaneous optical stimulation and electronic recording.

Purpose of the Study:

• To present a novel application-specified integrated circuit (ASIC) for intelligent optoelectronic probes.
• To enable simultaneous optical neural stimulation and electronic recording for advanced neuromodulation.

Main Methods:

• Designed an ASIC with four low-noise recording channels for local field potentials (LFPs).
• Integrated six independently addressable optical driver circuits for LED stimulation with intensity and pulse-width modulation.
• Implemented a digital interface using a serial peripheral interface (SPI) protocol and a finite state machine (FSM).

Main Results:

• Achieved low noise recording (2.08 μV) for LFPs with a 0.1-300 Hz bandwidth.
• Provided independent control over LED stimulation via 8-bit resolution and pulse-width modulation.
• Demonstrated concurrent recording and stimulation in bench-top, in vitro, and in vivo experiments.

Conclusions:

• The developed ASIC facilitates intelligent optoelectronic probing for advanced neuromodulation.
• The system supports simultaneous recording and stimulation, crucial for closed-loop optogenetic control.
• The compact design and digital interface allow integration with embedded controllers for versatile research applications.