Digital Wireless Recording of Wideband Neuronal Activity in Freely-Moving Humans

DESCRIPTION (provided by applicant): Bio-Signal Group Corp. developed a miniature, low-power, wireless digital recording technology called digital telemetry (DT) for recording wideband neural signals in rats. DT is wireless, allowing the subject to move freely within 10 m of a receiver. DT digitizes neural signals at the electrode connector to avoid inductive noise pickup from movements, other people and signal transmission through changing ambient electrical fields. Compared to conventional 12-bit systems, DT digitizes small fast action potentials and large slow brain field potentials at 24-bit (4096 times greater) resolution making it unnecessary to separately filter the two signal bands. This allows the phase relations in action (single cell) and field (population) potentials to be captured without unrecoverable distortions. These (and additional) innovations of DT can overcome the technical barrier to recording wideband brain signals from moving and seizing epileptic patients. In collaboration with the Seizures Disorder Center at UCLA, we will 1) develop a user- interface for remote configuration of the on-subject transmitter; 2) make previously impossible recordings of wideband signals during movement, convulsive intra-ictal events, and post-ictal agitation; and 3) test in people whether the covariance of action potentials and fast field oscillations indexes the likelihood and origin of seizure. There are many good reasons to study how activity from individual neurons is organized into brain networks, and how the recruitment of individual neurons into synchronized population activity might underlie seizure and its cognitive consequences. Although electrode and surgical technology has advanced so wideband (field and action potentials) brain signals can be recorded using depth electrodes implanted in the brains of awake freely-behaving human epileptic patients, artifact-free recordings during movements and peri-ictal events cannot be made because of limitations in the required biomedical electronics.