Rheobase

Rheobase is a measure of membrane excitability. In neuroscience, rheobase is the minimal current amplitude of infinite duration (in a practical sense, about 300 milliseconds) that results in the depolarization threshold of the cell membranes being reached, such as an action potential or the contraction of a muscle. In Greek, the root "rhe" translates to current or flow, and "basi" means bottom or foundation: thus the rheobase is the minimum current that will produce an action potential or muscle contraction.