Lee, Taeju Park, Jee-Ho Chou, Namsun Cho, Il-Joo Kim, Seong-Jin Je, Minkyu 2024-01-19T14:02:36Z 2024-01-19T14:02:36Z 2022-04-03 2021-08 2169-3536 https://pubs.kist.re.kr/handle/201004/116607 Monitoring the electrical neural signals is an important method for understanding the neuronal mechanism. In particular, in order to perform a cell-type-specific study, it is necessary to observe the concentration of calcium ions using fluorescent indicators in addition to measuring the electrical neural signal. This paper presents a multimodal multichannel neural activity readout integrated circuit that can perform not only electrical neural recording but also fluorescence recording of neural activity for the cell-type-specific study of heterogeneous neuronal cell populations. For monitoring the calcium ions, the photodiode generates the current according to the fiuorescence expressed by the reaction between the genetically encoded calcium indicators and calcium ions. The time-based fiuorescence recording circuit then records the photodiode current. The electrical neural signal captured by the microelectrode is recorded through the low-noise amplifier, variable gain amplifier, and analog-to-digital converter. The proposed integrated circuit is fabricated in a 1-poly 6-metal (1P6M) 0.18-mu m CMOS process. The fiuorescence recording circuit achieves a recording range of 81 dB (75 pA to 860 nA) and consumes a power of 724 nW/channel. The electrical recording circuit achieves an input-referred noise of 2.7 mu V-rms over the bandwidth of 10 kHz, while consuming the power of 4.9 mu W/channel. The functionality of the proposed circuits is verified through the in vivo and in vitro experiments. Compared to the conventional neuroscience tools, which consist of bulky off-chip components, this neural interface is implemented in a compact size to perform multimodal neural recording while consuming low power. English Institute of Electrical and Electronics Engineers Inc. A Multimodal Neural Activity Readout Integrated Circuit for Recording Fluorescence and Electrical Signals Article 10.1109/ACCESS.2021.3107299 1 IEEE Access, v.9 IEEE Access 9 Y scie scopus 000761506400002 2-s2.0-85113883792 Computer Science, Information Systems Engineering, Electrical & Electronic Telecommunications Computer Science Engineering Telecommunications Article CHOPPER AMPLIFIER IMPEDANCE ARRAY ELECTRODES RANGE PROBE MICE Brain-machine interface heterogeneous cell population fluorescence recording calcium ion genetically encoded calcium indicator GECI G-CaMP R-CaMP electrical neural recording