A Wireless Trimodal Neural Interface Device with Electrical and Electrochemical Recording

This paper introduces a wireless trimodal neural interface device capable of electrical neural recording, electrochemical neural recording, and optogenetic stimulation. The analog front-end (AFE) for electrical recording features a midband voltage gain of 60 dB, a bandwidth of 1–200 Hz, and an input referred noise voltage of $\mathbf{5}\ \boldsymbol{\mu}\mathbf{V}_{\mathbf{RMS}}$. The electrochemical recording AFE contains a potentiostat with a transimpedance gain of $\mathbf{100}\ \mathbf{k}\mathbf{\Omega}$ and input referred noise current of $\mathbf{50.2}\ \mathbf{pA}_{\mathbf{RMS}}$ and a fast-scan cyclic voltammetry (FSCV) waveform generator with a 400 V/s scan rate at a period of 100 ms. The LED driver holds the configurable optogenetic stimuli with options to adjust the LED current of up to 10 mA, pulse duration of 1–10 ms, and frequency of 1–10 Hz. To eliminate any tethering, a bidirectional Bluetooth Low Energy (BLE) link is established between the neural interface device and an external data receiver (i.e., USB dongle) to receive optogenetic configuration parameters and send back recorded data. A graphical user interface (GUI) displays optogenetic stimuli controls and graphs recorded data in real time.