# Modeling and Analysis of Environmental Electromagnetic Interference in Multiple-Channel Neural Recording Systems for High Common-Mode Interference Rejection Performance

## TL;DR

This paper models and reduces environmental electromagnetic interference in multi-channel neural recording systems to improve signal quality.

## Contribution

The paper introduces equivalent circuit models and design guidelines for high common-mode interference rejection in neural recording systems.

## Key findings

- The proposed models reduced 50 Hz EMI interference by three orders of magnitude in unshielded environments.
- Signal quality of recorded neural action potentials was maintained after interference reduction.
- In vivo experiments validated the effectiveness of the design guidelines on a 32-channel system.

## Abstract

Environmental electromagnetic interference (EMI) has always been a major interference source for multiple-channel neural recording systems, and little theoretical work has been attempted to address it. In this paper, equivalent circuit models are proposed to model both electromagnetic interference sources and neural signals in such systems, and analysis has been performed to generate the design guidelines for neural probes and the subsequent recording circuit towards higher common-mode interference (CMI) rejection performance while maintaining the recorded neural action potential (AP) signal quality. In vivo animal experiments with a configurable 32-channel neural recording system are carried out to validate the proposed models and design guidelines. The results show the power spectral density (PSD) of environmental 50 Hz EMI interference is reduced by three orders from 4.43 × 10−3 V2/Hz to 4.04 × 10−6 V2/Hz without affecting the recorded AP signal quality in an unshielded experiment environment.