Paroxysmal depolarizing shift

A paroxysmal depolarizing shift (PDS) or depolarizing shift is a cellular manifestation of epilepsy. First, there is a Ca mediated depolarization, which causes voltage gated Na to open, resulting in action potentials. This depolarization is followed by a period of hyper-polarization mediated by Ca-dependent K channels or GABA-activated Cl influx.