Date of Award

January 2018

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Hal Blumenfeld

Abstract

Temporal lobe epilepsy remains a common and complex clinical entity whose underlying disease pathology is incompletely understood. While many structures been identified in contributing to these seizures, particular note should be given to the thalamus. Previous studies with imaging techniques and neurostimulation have suggested certain thalamic nuclei of interest, but their precise activity during seizures has yet to be elucidated. The goal of this study was to perform population and single neuron recordings of several different thalamic nuclei during temporal lobe seizures, namely, the anterior (ANT), centrolateral (CL) and ventral posteriomedial (VPM). We performed these studies in an established rat model of temporal lobe epilepsy. We found that multiunit activity (MUA) increased during seizures in ANT and VPM, and decreased in CL. Additionally, single unit juxtacellular recordings showed a decreased firing rate and a switch to increased burst firing in CL. Finally, analysis of MUA in VPM showed a significant increase in spindles during seizures. These results reinforce our hypothesis that different thalamic nuclei have different roles in temporal lobe epilepsy, and generally support their previously hypothesized physiologic and pathologic functions. As a limbic nucleus, ANT participates in seizure propagation. CL, on the other hand, is a component of arousal circuitry and likely participates in decreased consciousness during seizures. Lastly, the increased spindle activity in VPM is also seen in sleep or light anesthesia, and may contribute to cortical dysfunction.

Comments

This is an Open Access Thesis.

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