Grant: CIHR Fellowship

Epilepsy is among the most common neurological conditions and affects 300,000 Canadians. Medial temporal lobe epilepsy (MTLE) is the most common form. In many cases, seizures are thought to originate in the hippocampus, a brain structure critical for memory and a number of other cognitive functions. Removing parts of the hippocampus and medial temporal lobe is an established treatment that effectively relieves seizures. However, there are usually marked postoperative complications, such as memory deficits and psychiatric disturbances. To minimize postoperative cognitive deficits, we propose to develop a method that will localize, or map, subregions of the hippocampus. Such a map will enable us to determine which subregions are crucial for various functions. In doing so, we will be able to advise neurosurgeons in their surgical planning, to avoid removing subregions that would likely result in severe cognitive deficits. The hippocampus is a complex structure that mediate various brain functions. Different parts of the hippocampus display dissociable patterns of functional connectivity to the rest of the brain. We will leverage this varying connectivity to map hippocampal subregions. Importantly, we will use novel neuroimaging analysis techniques that will enable us to generate a hippocampal map that is unique to each individual. We will then assess the relationship between these subregions and several hippocampal functions, including memory, emotion, and topographical processing. Finally, we will validate the hippocampal maps in MTLE patients, in whom we will be able to directly measure hippocampal activity using intra-hippocampal electrodes. This project will significantly impact epilepsy research as it will enable us to identify hippocampal subregions that are functionally different. One day, these individual maps of hippocampal organization could be used to plan surgical procedures and minimize post-surgical cognitive deficits in patients with epilepsy.