Complex Action Potentials
Complex Action Potentials¶
Encountered with extracellular measurements.
This is like a Local Field Potential recording (if you have ever encountered that term before… for example in EEG), but it is distinct because in a Complex Action Potential, you can more clearly resolve the contribution of action potentials from individual neurons.
This compound action potential (CAP) is the algebraic summation of all the action potentials produced by all the fibres that were within range of the measurement electrode (and that were active within a small enough time window that they temporally summate).
At different distances away from the site of CAP initiation, the waveform can change shape if more than one fiber at the site of initiation was activated by the stimulus. This is because action potentials in different axons travel at different speeds down the length of the nerve. The waveform can also change shape if, at different locations along the nerve, different post-synaptic neurons are activated.