Sensing local field potentials with a directional and scalable depth electrode array

Objective. A variety of electrophysiology tools are available to the neurosurgeon for diagnosis, functional therapy, and neural prosthetics. However, no tool can currently address these three critical needs: (a) access to all cortical regions in a minimally invasive manner; (b) recordings with microscale, mesoscale, and macroscale resolutions simultaneously; and (c) access to spatially distant multiple brain regions that constitute distributed cognitive networks. Approach. We modeled, designed, and demonstrated a novel device for recording local field potentials (LFPs) with the form factor of a stereo-electroencephalographic electrode and combined with radially distributed microelectrodes. Main results. Electro-quasistatic models demonstrate that the lead body amplifies and shields LFP sources based on direction, enabling di rectional sensitivity and sc alability, referred to as the directional and scalable (DISC) array. In vivo, DISC demonstrated significantly improved signal-to-noise ratio, directional sensitivity, and decoding accuracy from rat barrel cortex recordings during whisker stimulation. Critical for future translation, DISC demonstrated a higher signal to noise ratio (SNR) than virtual ring electrodes and a noise floor approaching that of large ring electrodes in an unshielded environment after common average referencing. DISC also revealed independent, stereoscopic current source density measures whose direction was verified after histology. Significance. Directional sensitivity of LFPs may significantly improve brain-computer interfaces and many diagnostic procedures, including epilepsy foci detection and deep brain targeting.

Automated summary

Researchers have developed a novel device, called the directional and scalable (DISC) array, which combines a stereo-electroencephalographic electrode with radially distributed microelectrodes to record local field potentials (LFPs) with different resolutions simultaneously. The DISC array demonstrated improved signal-to-noise ratio, directional sensitivity, and decoding accuracy in rat barrel cortex recordings during whisker stimulation. The results suggest that the directional sensitivity of LFPs can significantly enhance brain-computer interfaces and various diagnostic procedures.