Voltage clamp is an electrophysiological technique to record electrical currents in biological membranes. It is based on the principle that the current flowing through a cell membrane can be estimated by “clamping” the membrane potential to a constant value using the injection of a mirror current – a current of the same amplitude but reversed polarity.
In practice, the method is used primarily to characterize voltage-dependent conductances in the membrane of neurons by clamping the cells to different stepping potentials. The clamp is achieved with a circuit that quickly detects deviations from the stepping potential and generates currents to correct this deviation. Knowing this current gives the current in the membrane.
KeywordsCurrent Injection Voltage Clamp Electrode Capacitance Measured Membrane Potential Dynamic Clamp
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