The Argo: a high channel count recording system for neural recording in vivo

Abstract

Objective. Decoding neural activity has been limited by the lack of tools available to record from large numbers of neurons across multiple cortical regions simultaneously with high temporal fidelity. To this end, we developed the Argo system to record cortical neural activity at high data rates. Approach. Here we demonstrate a massively parallel neural recording system based on platinum-iridium microwire electrode arrays bonded to a CMOS voltage amplifier array. The Argo system is the highest channel count in vivo neural recording system, supporting simultaneous recording from 65 536 channels, sampled at 32 kHz and 12-bit resolution. This system was designed for cortical recordings, compatible with both penetrating and surface microelectrodes. Main results. We validated this system through initial bench testing to determine specific gain and noise characteristics of bonded microwires, followed by in-vivo experiments in both rat and sheep cortex. We recorded spiking activity from 791 neurons in rats and surface local field potential activity from over 30 000 channels in sheep. Significance. These are the largest channel count microwire-based recordings in both rat and sheep. While currently adapted for head-fixed recording, the microwire-CMOS architecture is well suited for clinical translation. Thus, this demonstration helps pave the way for a future high data rate intracortical implant.

Analysis and Reduction of Nonlinear Distortion in AC-Coupled CMOS Neural Amplifiers with Tunable Cutoff Frequencies

“…The analysis presented in this section and the noise values given in Table 1 lead to conclusion that that the proposed design parameters ( C ina = C inb = 4 pF, C fa = C fb = 200 fF, K = 20) should allow for reasonably good noise performance, comparable with advanced multichannel neural amplifiers reported in the literature [ 10 , 28 ]. At the same time, the moderate gain value K = 20 V/V should help keeping the level of distortion under control.…”

“…Taking advantage of large numbers of closely spaced microelectrodes, such systems make it possible to record activity of large neuronal populations with resolution of individual neurons, providing new insights into processing and coding of information in the brain circuits. Systems with several hundred to a few thousand of channels are now routinely used for recording the brain activity in live animals [ 8 , 9 ] and a prototype device with tens of thousands of recording channels was reported recently [ 10 ]. Systems dedicated to large-scale recording of brain activity in human are also being developed [ 11 ].…”

Carbon Fiber Electrodes for Intracellular Recording and Stimulation

“…While many novel high channel count neural recording systems are now being deployed [39][40][41], these are limited to extracellular potentials, where interactions between neurons can only be inferred indirectly. Although the intracellular recordings presented here are shown in invertebrate preparation, the anecdotal report of intracellular-like potentials in a songbird model [12] might suggest that this technique could be optimized for short term intracellular recordings in mammals, using a microdrive.…”

Recording Strategies for High Channel Count, Densely Spaced Microelectrode Arrays

“…Similarly, in Rajangam et al (2016), six multielectrode arrays with 96 microwires each were used totalling 576 recording sites. More recently, the trend is toward including more electrodes per individual shank or microwire bundle and, thus, for instance, the Neuropixel probe (Jun et al, 2017) has 960 sites on a single, 10 mm long, non-tapered shank with 70×20 µm cross-section and the Argo system (Sahasrabuddhe et al, 2020) uses a single microwire bundle with 1300 electrodes (10 mm array diameter, 18 µm wire diameter, 200 µm spacing, 1 mm length), which can be extended to 30,000 channels for surface LFP recordings.…”