PROJECT TITLE :

Neurochemostat: A Neural Interface SoC With Integrated Chemometrics for Closed-Loop Regulation of Brain Dopamine

ABSTRACT:

This paper presents a three.three×3.2 mm2 system-on-chip (SoC) fabricated in AMS zero.35 μm 2P/4M CMOS for closed-loop regulation of brain dopamine. The SoC uniquely integrates neurochemical sensing, on-the-fly chemometrics, and feedback-controlled electrical stimulation to appreciate a “neurochemostat” by maintaining brain levels of electrically evoked dopamine between 2 user-set thresholds. The SoC incorporates a ninety μW, custom-designed, digital signal processing (DSP) unit for real-time processing of neurochemical information obtained by four hundred V/s fast-scan cyclic voltammetry (FSCV) with a carbon-fiber microelectrode (CFM). Specifically, the DSP unit executes a chemometrics algorithm based upon principal element regression (PCR) to resolve in real time electrically evoked brain dopamine levels from pH change and CFM background-current drift, two common interferents encountered using FSCV with a CFM in vivo. Any, the DSP unit directly links the chemically resolved dopamine levels to the activation of the electrical microstimulator in on-off-keying (OOK) fashion. Measured results from benchtop testing, flow injection analysis (FIA), and biological experiments with an anesthetized rat are presented.