Imaging episodic memory during development and childhood epilepsy

Epilepsy affects 2.2 million adults in the USA, with 1 in 26 people developing epilepsy at some point in their lives. Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy as medial structures, and the hippocampus in particular, are prone to generating seizures. Selective anterior temporal resection (which removes the hippocampus) is the most effective intractable TLE treatment, but given the critical role of the mesial temporal lobe in memory functioning, resection can have negative effects on this crucial cognitive skill. To minimize the adverse impact of temporal lobe surgery on memory functioning, reliable pre-surgical guides are needed. Clinical functional magnetic resonance imaging (fMRI) provides reliable, noninvasive guidance of language functioning and plays a growing role in the pre-surgical evaluation for epilepsy patients; however, localization of memory function in children with epilepsy using fMRI has not been established. Aside from the lack of neuroimaging memory studies in children with TLE, studies of typical development are limited. This review will focus on the functional anatomy of memory systems throughout development, with a focus on TLE. TLE provides the ideal model from which to understand memory function and the limits of plasticity and compensation/reorganization throughout development.