An integrated system for multichannel neuronal recording with spike/LFP separation, integrated A/D conversion and threshold detection.
A mixed-signal front-end processor for multichannel neuronal recording is described. It receives 12 differential-input channels of implanted recording electrodes. A programmable cutoff High Pass Filter (HPF) blocks dc and low-frequency input drift at about 1 Hz. The signals are band-split at about 200 Hz to low-frequency Local Field Potential (LFP) and high-frequency spike data (SPK), which is band limited by a programmable-cutoff LPF, in a range of 8-13 kHz. Amplifier offsets are compensated by 5-bit calibration digital-to-analog converters (DACs). The SPK and LFP channels provide variable amplification rates of up to 5000 and 500, respectively. The analog signals are converted into 10-bit digital form, and streamed out over a serial digital bus at up to 8 Mbps. A threshold filter suppresses inactive portions of the signal and emits only spike segments of programmable length. A prototype has been fabricated on a 0.35-microm CMOS process and tested successfully, demonstrating a 3-microV noise level. Special interface system incorporating an embedded CPU core in a programmable logic device accompanied by real-time software has been developed to allow connectivity to a computer host.
Perelman
Yevgeny
Y
VLSI Systems Research Center, Department of Electrical Engineering Technion-Israel Institute of Technology, Haifa 32000, Israel. perelman@tx.technion.ac.il
Ginosar
Ran
R
D000200:Action Potentials / Q000502:physiology*; D000669:Amplifiers, Electronic; D000703:Analog-Digital Conversion; D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology; D004056:Differential Threshold / Q000502:physiology; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D009474:Neurons / Q000502:physiology*; D051381:Rats; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D018511:Systems Integration