A Multimodal Multichannel Neural Activity Readout IC with 0.7 mu W/Channel Ca2+-Probe-Based Fluorescence Recording and Electrical Recording

Abstract

This paper presents a multimodal multichannel neural activity readout IC which can perform not only the electrical recording (ER) but also the fluorescence recording (FR) of neural activity for the cell-type-specific study of heterogeneous neuronal cell populations. The time-based FR circuit senses Ca2+ concentration using Ca(2+)probes while the ER circuit acquires action potentials (APs) and local field potentials (LFPs). The IC is fabricated in 0.18 mu m CMOS, The FR circuit achieves a recording range of 81dB (75pA to 860nA) and consumes the power of 0.7 mu W/Ch. The ER circuit achieves the input-referred noise (IRN) of 2.7 mu V-rms over the bandwidth (BW) of 10kHz, while consuming the power of 4.9 mu W/Ch. The in-vitro measurement is performed for recording Ca2+ concentration and electrical neural signals.