In temporal lobe epilepsy (TLE) the epileptogenic focus is focal and unilateral in the majority of patients. A key characteristic of focal TLE is the presence of sub-clinical epileptiform activity in both the ictal and contralateral "healthy" hemisphere. Such interictal activity is clinically important as it may reflect the spread of pathology, potentially leading to secondary epileptogenesis. The role played by white matter pathways in this process are unknown