Ab Initio Physics Considerations in the Design of Wireless and Non-Invasive Neural Recording Systems Using Magnetoelectric Nanoparticles

Magnetoelectric nanoparticles (MENPs) provide a way to wirelessly and non-invasively record local neural activity deep in the brain. When administered into the brain, MENPs serve as auxiliary 3-D sources, thus offering a solution to the fundamental problem of inverse mathematics that has stifled the advancement in the field of wireless neural recording from its inception. Due to the magnetoelectric effect, the MENPs’ magnetization is modulated by electric fields due to local neural activity. In turn, this modulated magnetization can be detected via modern magnetometers such as optical pumped magnetometers (OPMs) and nitrogen-vacancy (NV) center devices, already impacting the state of magnetoencephalography (MEG). This basic physics study discusses an aspect that has not been explored to date. There is a strong dependence of the MENPs-based recording on the specific location of the nanoparticles with respect to the neuronal microstructure. This analysis shows that one of the key conditions to enable the MENPs-based recording with a sub-10−3 cm3 spatial resolution in real time would be to ensure the nanoparticles are located specifically on the membrane, where the neural-firing-caused electric field reaches its maximum value. One potential implementation of this high-resolution recording concept would be to integrate MENPs with the recently emerged magnetic particle imaging (MPI).