In neuroscience

Neuroscience

Neuroscience is the scientific study of the nervous system. Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics,...

, rheobase is the minimal current amplitude of indefinite duration (practically, a few hundred milliseconds) that results in the depolarization threshold of the cell membranes being reached (i.e. an action potential

Action potential

In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and...

 or the contraction of a muscle).

In the case of a nerve or single muscle

Muscle

Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

 cell, rheobase is half the current that needs to be applied for the duration of chronaxie

Chronaxie

In the mathematical description of the functioning of the nervous system, the chronaxie is the minimum time over which an electric current, double the strength of the rheobase, needs to be applied, in order to stimulate a muscle fiber or nerve cell.The terms "chronaxie" and "rheobase" were coined...

to result in an action potential or muscle twitch. This can be understood better by looking at a strength duration relationship (Fig. 1).