Silver nanoparticle-enhanced plasmonic front-end for wideband scalp electrometry

Abstract

Conventional electroencephalography mainly measures slow voltage changes on the scalp. It usually finds brain rhythms later using filtering and spectrum analysis, so it is hard to test precise timing links across very different frequencies, and the results can be easily affected by non-brain noise. Here, we introduce the Dodecanogram (DDG), a brain signal recording system that keeps timing and phase information while measuring signals in 12 parallel bands from 1 Hz to 5.31 GHz. DDG uses 12 probes (additional two reference channels) made of small Yagi antenna arrays connected to a silver nanoparticles-coated silicon interface, which passively concentrates nearby fields. The signals then pass through band-selective analog circuits and are digitized using comparator-based electronics. A synchronized logic analyzer records all bands at once, allowing us to detect short bursts and compute phase and coherence without scanning bands one by one. In this advanced instrumentation-validation and proof-of-concept study, DDG data from the human subjects showed reproducible task-linked multiband patterns together with inter-subject variability. Low-arousal states had weaker broadband activity with more stable phase patterns, while high-arousal states showed stronger multiband activity, more short-lived phase groupings, and more frequent phase slips. DDG provides an engineering platform to test cross-band phase organization in extended-band brain recordings, and it motivates larger studies with phantoms, shielding, and multi-subject controls to separate neural signals from environmental and contact effects.