Cortec brain interchange in freely behaving canine

presentation, poster

English

Objective: We report our initial experience with the CorTec Brain Interchange, a fully implantable bi-directional system for chronic nervous system tracking and interaction. Because canines are large enough to accommodate devices designed for humans, they are a good model system for the preclinical research required to develop an implantable bi-directional system for tracking electrophysiology, implementing algorithms, and adaptive stimulation. Methods: A healthy 24-month-old beagle (canis familiaris) named Laika was implanted with the CorTec Brain Interchange system. The CorTec Brain Interchange device features up to 32 channels for local field potential recording and electrical stimulation. Two grids (20 total channels) were implanted through bilateral craniotomies into the subdural space spanning frontal and parietal canine cortex. The subdural grid electrode tails were tunneled to the shoulder, adjacent to the scapula, and connected to the internal electronics unit. The internal electronics unit in the shoulder inductively couples via a telemetry wand to an external interchange box for data streaming onto a computer using BCI2000 (1kHz Sampling Rate, Dynamic Range 0.5 - 450 Hz). Local field potentials were obtained in three different activities as ascertained by simultaneous video: 1) quiet wakefulness 2) movement and 3) sleep. The power spectral density in the three activities were analyzed. The LFP signals were segmented into 10-second-long epochs. The data were then filtered by a 0.5-200 Hz band-pass filter, and power spectral density (PSD) was estimated using Welch’s method for each 10-second-long epoch. Results: The CorTec Brain Interchange system provided continuous data streaming that was only limited by the ability to maintain a physical connection between the magnet in the implant and the magnet in the coupling device of the telemetry wand. Recordings of up to 30 minutes in duration were obtained. The PSD for the 3 activities showed spectral changes enabling differentiation of wake, movement, and slow-wave sleep. Conclusions: These preliminary results demonstrate the feasibility of continuous streaming of cortical electrophysiology in a behaving canine with the CorTec Brain Interchange. Simple spectral measures were shown to identify behavioral state, wake, and sleep. Future plans include further engineering refinements for reliable coupling of the device, reduction of artifact, and the ability to stimulate. All of these are required for a clinical brain computer interface trial in humans, and this technical experience represents a meaningful step toward this.

epilepsy; implantable neural stimulator; canine

WORRELL, S.; MÍVALT, F.; KIM, I.; BELSTEN, A.; BRUNNER, P.; MESSINA, S.; KAUFMAN, T.; STAFF, N.; HERMES, D.; WORRELL, G.; SCHALK, G.; MILLER, K.

8. 11. 2021

Society for Neuroscience

Chicago, the United States of America

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