Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Neuroscience

Supervisor

Leung, LS

2nd Supervisor

Mirsattari, Seyed M.

Co-Supervisor

Abstract

Absence epilepsy is characterized by brief spells of absent stare and spike wave discharges (SWDs), generally believed to be generated by a thalamocortical network. Our lab showed that hippocampal neuronal firings were synchronous with SWDs in a gamma butyrolactone (GBL) model of absence epilepsy in rats (Arcaro et al., 2016). We hypothesize that, in a GBL model of absence seizures, 30-400 Hz oscillations in the spontaneous local field potentials (LFPs) in the hippocampus and other parts of limbic system (amygdala and nucleus accumbens) are phase modulated by SWDs, and this modulation is mediated through nucleus reuniens of midline thalamus (RE). Spontaneous LFPs in the hippocampus, thalamus, frontal cortex, nucleus accumbens and amygdala were recorded before and after GBL injection. Phase modulation of three frequency bands (30-80 Hz gamma, 80-250 Hz ripples and 250-400 fast ripples) by 2-6 Hz frequency increased for >30 min after GBL injection. In another group of rats, the modulation index (MI) of gamma, ripples and fast ripples in specific brain areas after GBL was smaller after muscimol as compared to saline infusion into the RE. MI of the different frequency bands appears to be a sensitive measure of the effect of SWD on each brain area and RE is an important link between thalamus and hippocampus.

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