Master of Science
Mesial temporal lobe epilepsy (TLE) is the most common form of focal epilepsy and is often resistant to medication. Recent studies have noted brain-wide disruptions to several neural networks in so-called “focal” epilepsy, notably TLE, leading to it being recognized as a network disease. We aimed to assess the integrity of functional networks while they were simultaneously activated in an ecologically valid manner, using an actively engaging, richly stimulating audio-visual film clip. This stimulus elicits widespread, dynamic patterns of time-locked brain activity, measurable using functional magnetic resonance imaging. Thirteen persons with drug-resistant TLE (persons with epilepsy; PWE) and 10 demographically matched controls were scanned while at rest and while watching a suspenseful movie clip in a 3T MRI system. We observed idiosyncratic activation in several functional networks among PWE during movie-viewing. Activation time courses among PWE synchronized poorly with the highly stereotyped movie-driven BOLD fluctuations exhibited by controls [i.e., high inter-subject correlation (ISC)]. We also examined coupling (functional connectivity) among 10 canonical functional networks during resting-state and movie-viewing conditions. Whereas functional networks in healthy viewers segregate to support movie processing, the auditory and dorsal attention networks among PWE do not segregate as efficiently. Furthermore, we observed a robust pattern of connectivity alterations in temporal and extratemporal regions during movie viewing in PWE compared to controls. Our findings supplement evidence derived from resting-state fMRI and provide novel insight into how the cognitively engaged brain is altered in TLE.
Bullen, Alenka, "Movie-driven fMRI Reveals Network Asynchrony and Connectivity Alterations in Temporal Lobe Epilepsy" (2017). Electronic Thesis and Dissertation Repository. 4827.