Kernel Flux: a whole-head 432-magnetometer optically-pumped magnetoencephalography (OP-MEG) system for brain activity imaging during natural human experiences
Ethan J. Pratt, M. P. Ledbetter, Ricardo Jiménez-Martínez, Benjamin Shapiro, Amelia J. Solon, Geoffrey Z. Iwata, Steve Garber, Jeff Gormley, Dakota Decker, David A. Delgadillo, A. T. Dellis, Jake Phillips, Guhan Sundar, Jerry Leung, Jim Coyne, Mike McKinley, Gilbert Lopez, Scott Homan, Lucas Marsh, Mary Zhang, Vincent Maurice, Benjamin Siepser, Teresa Giovannoli, Brandon Leverett, Gabriel Lerner, Scott H. Seidman, Vicente DeLuna, Kayla Wright-Freeman, Julian Kates‐Harbeck, Teague Lasser, Hooman Mohseni, Tara Sharp, Anthony N. Zorzos, Antonio H. Lara, Ali Kouhzadi, Alejandro González‐Ojeda, Pronoy Chopra, Zachary Bednarke, Michael Henninger, Jamu K. Alford
Abstract
MEG based on optically-pumped magnetometry (OP-MEG) operates with miniaturized, wearable insulation, in contrast to massive cryogenic dewars for SQUID-MEG, and allows placement of the sensors close to the scalp. This allows more natural head motion during data recording and localized signal quality comparable to, or surpassing, SQUID-MEG. However no OP-MEG system to date has offered full-head coverage with dense sensor packing, and existing systems - as with SQUID-MEG - require the subject to be sealed in a multilayer, passively-shielded vault in order to suppress ambient magnetic fields. Here we present Kernel Flux, which overcomes these limitations. Kernel Flux uses a collection of alkali vapor sensors in a unique array architecture to directly detect the magnetic fields generated by collective neural activity in the brain, while allowing for comfortable head motion. Each Kernel Flux OP-MEG system was designed from the ground up to work as an integrated system optimized around the user's experience, with relevance to natural home and office contexts.