An Integrated System for Multichannel Neuronal Recording With Spike/LFP Separation, Integrated A/D Conversion and Threshold Detection

Abstract

Abstract-A mixed-signal front-end processor for multichannel neuronal recording is described. It receives twelve differential-input channels of implanted recording electrodes. A programmable cutoff HPF blocks DC and low frequency input drift at about 1Hz. The signals are band-split at about 200Hz to low-frequency local field potential (LFP) and high-frequency spike data (SPK), which is band limited by a programmablecutoff LPF, in a range of 8-13kHz. Amplifier offsets are compensated by 5-bit calibration 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 8Mbps. A threshold filter suppresses inactive portions of the signal and emits only spike segments of programmable length. A prototype has been fabricated on a 0.35µm CMOS process and tested successfully, demonstrating a 3µV 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.

Simultaneous wireless electrophysiological and neurochemical monitoring

“…16 A versatile VLSI system which can interface to all these modalities is highly desirable. Several VLSI systems have been developed previously [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] to acquire different neural signals. Typically the range of frequencies covered by any one of these systems is limited to one or two signal modalities, to accommodate high efficiency for the targeted application.…”

From spikes to EEG: Integrated multichannel and selective acquisition of neuropotentials

“…The low noise figure was achieved using chopper stabilization technique and external components. Recently, Perelman et al [17] showed on-chip amplification and separation of spikes from LFPs. The amplifier draws 75 µA from the supply for an input-referred noise of 3 µV.…”

Spike detection algorithm improvement, spike waveforms projections with PCA and hierarchical classification

“…New technologies have been developed in order to overcome the experimental difficulties which limit the number of neurons studied at the same time, the temporal constraints due to the placement of the electrodes and the mechanical damage of the cells during the functional study. In this context, MicroElectrode Arrays (MEA) have been designed [6]. Planar MEA, like electrodes matrixes, have been spread for the first time in the 1970s.…”