Analyzing the Scalability of Parallel Microwire Arrays for Neural Recording

Brain-computer interfaces (BCI) improve the quality of life for patients with severe motor disabilities and sensory impairment by providing them a direct way to communicate with the outside world through computers. To gain higher temporal resolution for better devices, intracortical neural electrodes, such as microwire arrays, are used. Microwire electrode arrays bonded to CMOS sensors, for intracortical neural recordings, have been claimed to be scalable. Microwire electrode arrays of varying diameters and densities were constructed and evaluated for percentage connectivity after interfacing with a custom-made CMOS sensor. The results demonstrate that there is no significant difference in the mean connectivity between a 3 mm and a 12 mm bundle as well as between arrays that have a wire-to-wire distance of 200 μm versus 100 μm, confirming the scalability of microwire electrode arrays. Understanding array scalability allows for better electrodes to be built for higher resolution neural recordings, which can help those who suffer from motor or sensory disabilities regain a better quality of life by re-establishing some independence

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

ObjectiveDecoding 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.ApproachHere 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 resultsWe 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.SignificanceThese 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