Recent advances in epilepsy stem from the notion that a network of brain areas, as opposed to a single onset zone, may be responsible for the onset and maintenance of seizures. This is critical as identifying and completely resecting the epileptogenic zone while preserving healthy eloquent cortex is considered to be the basis of the successful surgical treatment of epilepsy. However, methods to localize and quantitatively study the properties of these networks need to be improved. Recent advances in neuroscience include the development of tools for the analysis of cortical networks using graph theory and the identification of high frequency activity on EEG that correlates with neuronal population firing. Quantifying the connectivity between brain areas with graph theory allows comparison of normal and abnormal brain networks. Availability of a marker of highly localized neuronal population activity that can be recorded by conventional clinical electrodes offers a means to track brain activation rapidly as it propagates through cortex. Here, we propose to bridge the gap between current clinical practice that results in suboptimal surgical outcomes and a more detailed understanding of cortical networks and the spread of epileptic To determine the relationship between networks derived from neuroimaging and electrophysiology techniques, and 2) To localize functional and pathological networks using complementary methods from multiple recording techniques. The long term goal of this research is the application of network analysis to multimodal imaging to 1) better understand the relationship between non-invasive and invasive imaging and 2) develop more accurate techniques to localize epileptic networks to improve surgical outcome, both of which will be addressed in this proposal. This proposed study has two fundamental goals.
The cure rate of surgery for patients with epilepsy originating outside the temporal lobe continues to be less than 50% despite improvements in surgery and brain imaging. This low rate of success likely stems from the fact that our techniques to define epileptic regions of the brain are limited and cannot be identified at the time of surgery. This project proposes to develop novel methods for identifying the areas in the human brain which may be safely removed to control seizures not stopped by medications. This research has important significance in improving efficacy of localizing the seizure zone and developing tools to improve surgical outcome.
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