Cellular electrophysiology: modeling and simulation

All cells have a difference in voltage across the cell membrane. This is the so-called membrane potential. Some cells, such as neurons and muscle cells, use the membrane potential as a signal. In that case, a cell may be stimulated by application of a small current during a short time period. If the current is sufficiently strong, the membrane potential goes through a large excursion, which is called an action potential, before returning to its resting value. Action potentials are used as signaling mechanism in the brain and to initiate muscular contraction. Cells that are able to generate an action potential are excitable. Examples of excitable cells are neurons, cardiac cells, and smooth and skeletal muscle cells. By establishing electrical connections between the cells, action potentials can propagate through a network of connected cells. Electrical connections between neurons are usually established via synapses, while cardiac muscle cells are electrically connected through so-called gap junctions [5].