# Epileptic seizure clustering and accumulation at transition from activity to rest in GAERS rats

## TL;DR

This study found that seizures in a rat model of epilepsy tend to cluster when the animals transition from active to resting states.

## Contribution

The study reveals that transitions between behavioral states influence seizure occurrence in GAERS rats.

## Key findings

- Seizures in GAERS rats tend to occur in bursts and are more likely around transitions from activity to rest.
- Seizures are associated with changes in activity marker power before seizure onset.
- GAERS rats have longer continuous episodes of activity and rest compared to controls.

## Abstract

Knowing when seizures occur may help patients and can also provide insight into epileptogenesis mechanisms. We recorded seizures over periods of several days in the Genetic Absence Epileptic Rat from Strasbourg (GAERS) model of absence epilepsy, while we monitored behavioral activity with a combined head accelerometer (ACCEL), neck electromyogram (EMG), and electrooculogram (EOG). The three markers consistently discriminated between states of behavioral activity and rest. Both GAERS and control Wistar rats spent more time in rest (55–66%) than in activity (34–45%), yet GAERS showed prolonged continuous episodes of activity (23 vs. 18 min) and rest (34 vs. 30 min). On average, seizures lasted 13 s and were separated by 3.2 min. Isolated seizures were associated with a decrease in the power of the activity markers from steep for ACCEL to moderate for EMG and weak for EOG, with ACCEL and EMG power changes starting before seizure onset. Seizures tended to occur in bursts, with the probability of seizing significantly increasing around a seizure in a window of ±4 min. Furthermore, the seizure rate was strongly increased for several minutes when transitioning from activity to rest. These results point to mechanisms that control behavioral states as determining factors of seizure occurrence.