Neuronal populations in the brain achieve levels of synchronous electrophysiological activity during both normal brain function and... Show moreNeuronal populations in the brain achieve levels of synchronous electrophysiological activity during both normal brain function and pathological states such as epileptic seizures. Understanding how the dynamics of neuronal oscillators in the brain evolve from normal to diseased states is a critical component towards decoding such complex behaviors. In my studies, I assessed multi-site dynamics underlying seizure evolution in limbic epilepsy by analyzing oscillators in recordings of local field potentials from three brain structures (bilateral hippocampi and anteromedial thalamus) in a rat model of temporal lobe epilepsy extracted using the empirical mode decomposition (EMD) technique. The analysis revealed patterns of multi-site phase coherence during initiation and termination phases of seizures. The multi-site synchrony events as seizures naturally terminated were used to model electrical deep brain stimulation (DBS) protocols aimed at stopping ongoing epileptic seizures. The location and frequency of the natural termination synchrony varied between subjects but was stable in time within each animal. My studies reveal that DBS protocols were significantly more effective at rapidly stopping seizures when the frequency and location of multi-site stimulation reflected the endogenous synchrony dynamics observed in each subject. These results strongly suggest that tailoring DBS protocols to individual endogenous rhythms that may represent how brains naturally resolve epileptic seizures could play a critical role in vastly improving the overall efficacy of this important therapy. Ph.D. in Biomedical Engineering, December 2015 Show less
