Signal and Noise Sources from Microwire Arrays Implanted in Rodent Cortex

Microelectrode arrays are commonly used in neuroscience experimentation, but detailed engineering-oriented characterizations of these devices are rarely found in the literature. This manuscript presents spectral and time domain measurements from microwire arrays (TDT) implanted in rodent cortex. Characterizations of thermal noise, local field potentials, and action potential activity were performed with custom low noise electronics as well as a commercial neural recording system. The measurements show spectral characteristics relevant to noise specifications for front-end electronics designed for neural recording, often referred to as “neural amplifiers.” Background noise levels in different frequency bands were quantified, and suggest lower noise specifications for front-end electronics than are often used in state-of-the-art designs. The measurements are also relevant to understanding intracortical recordings in general, particularly in less explored regions of the spectrum.