Current Clamp
The current clamp method is used in electrophysiology to record the voltage of a cell membrane following an electric stimulus.
Not to be mistaken with the voltage clamp method, the current clamp method consists of an electrode that both records and injects current (flow of ions) inside a neuron. An additional electrometer outside the cell results in the recording of the resulting voltage. This technique could be used for example to mimic the electrical signal coming from a synapse and neurotransmitters, and observe their effect on the voltage of the axon membrane of a neuron.
Figure 1: Example of voltage recording with the current clamp method
When the electrode does not inject current, the recorded voltage is the resting membrane potential, usually around -70 mV for neuronal membranes.
The current is usually injected in the form of short pulses, which are visualized as "square" signals on the recordings.