A DC-sensitive video/electrophysiology monitoring unit for long-term continuous study of seizures and seizure-associated spreading depolarization in a rat model

There has been a long-term need for a low-cost, highly efficient, and high-fidelity epilepsy monitoring unit (EMU) suitable for home-cage monitoring of small-animal models of epilepsy. We show an accessible, scalable, highly space and energy-efficient EMU capable of fulfilling chronic, continuous synchronized multiple animal monitoring jobs. Each rig within the EMU can provide 16-channel high-fidelity, DC-sensitive biopotential recordings, head acceleration monitoring, synchronized voltammetry applications, and video recording on one freely moving rat. We present the overall EMU architecture design and subsystem details in each recording rig. We demonstrate long-term continuous in vivo recordings of spontaneous seizure and seizure-associated spreading depolarization (SD) from freely moving rats prepared under the tetanus toxin model of temporal lobe epilepsy. Significance StatementLong-term continuous DC-sensitive biopotential and video recordings are essential for capturing the dynamics of epileptic seizures and seizure-related spreading depolarizations (SD), providing a deeper understanding of their underlying mechanisms. These recordings are invaluable for developing animal models of epilepsy, studying seizure prediction, drug testing, and investigating related neurological conditions such as mental health, aging, and dementia. They also reveal rare phenomena that short-duration recordings might miss. However, traditional methods are resource intensive. The new epilepsy monitoring unit (EMU) introduced in this paper offers a cost-effective and space-saving solution for high-fidelity chronic monitoring of freely moving animals, utilizing compact single-board computers and standard cages without interrupting the recordings.