= Current clamp
<Current clamp> prescribes injected <electric current> while recording <membrane potential>. A constant command does not force <membrane potential> to remain constant: a <neuron> can produce <action potentials> or <synaptic potentials> while that command is unchanged. At zero commanded <electric current>, the amplifier still measures <membrane potential>; intrinsic ionic <electric currents> continue. The name concerns current supplied by the instrument, not the cancellation of all currents in the <biological cell>.
In <whole-cell recording>, the measured pipette voltage during a current pulse includes the <patch-clamp series resistance> drop. A modern authored methods article explicitly describes current-pulse protocols and this distortion.<Multiple Two-Photon Targeted Whole-Cell Patch-Clamp Recordings From Monosynaptically Connected Neurons in vivo by Jean-Sébastien Jouhanneau and others>[Intracellular Current Injection; Step 5: Whole-Cell Configuration]{ref} Check the access contribution with small pulses and distinguish the immediate pipette-voltage jump from the slower <membrane capacitance> response. A zero-input interval measures a baseline, not proof that the instrument has no voltage offset. The passive example below explains these distinctions without asserting any new physiological measurements.
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