title: Neurochemostat: A Neural Interface SoC With Integrated Chemometrics for Closed-Loop Regulation of Brain Dopamine.
abstract: This paper presents a 3.3×3.2 mm(2) system-on-chip (SoC) fabricated in AMS 0.35 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 realize a "neurochemostat" by maintaining brain levels of electrically evoked dopamine between two user-set thresholds. The SoC incorporates a 90 μW, custom-designed, digital signal processing (DSP) unit for real-time processing of neurochemical data obtained by 400 V/s fast-scan cyclic voltammetry (FSCV) with a carbon-fiber microelectrode (CFM). Specifically, the DSP unit executes a chemometrics algorithm based upon principal component 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. Further, 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.
authors.forename: Bardia
authors.initials: B
authors.lastname: Bozorgzadeh
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Schuweiler
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Bobak
authors.forename: Paul A
authors.initials: PA
authors.lastname: Garris
authors.forename: Pedram
authors.initials: P
authors.lastname: Mohseni
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation*; D001921:Brain / Q000378:metabolism*; D004298:Dopamine / Q000032:analysis*; D004558:Electric Stimulation; D055664:Electrochemical Techniques / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D008839:Microelectrodes; D025341:Principal Component Analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013686:Telemetry / Q000295:instrumentation / Q000379:methods
chemical_list: D004298:Dopamine