WONOEP appraisal: molecular and cellular imaging in epilepsy

Great advancements have been made in understanding the basic mechanisms of ictogenesis using single-cell electrophysiology (e.g., patch clamp, sharp electrode), large-scale electrophysiology (e.g., electroencephalography [EEG], field potential recording), and large-scale imaging (magnetic resonance imaging [MRI], positron emission tomography [PET], calcium imaging of acetoxymethyl ester [AM] dye-loaded tissue). Until recently, it has been challenging to study experimentally how population rhythms emerge from cellular activity. Newly developed optical imaging technologies hold promise for bridging this gap by making it possible to simultaneously record the many cellular elements that comprise a neural circuit. Furthermore, easily accessible genetic technologies for targeting expression of fluorescent protein-based indicators make it possible to study, in animal models of epilepsy, epileptogenic changes to neural circuits over long periods. In this review, we summarize some of the latest imaging tools (fluorescent probes, gene delivery methods, and microscopy techniques) that can lead to the advancement of cell- and circuit-level understanding of epilepsy, which in turn may inform and improve development of next generation antiepileptic and antiepileptogenic drugs.