Spike directivity is a vector that quantifies changes in transient charge density during action potential propagation.Aur D., Connolly C.I., Jog M.S., (2005) Computing spike directivity with tetrodes, Journal of Neuroscience Methods, 149 (1), pp. 57–63.
The digital-like uniformity of action potentials is contradicted by experimental data. Electrophysiologists have observed that the shape of recorded action potentials changes in time. Recent experimental evidence has shown that action potentials in neurons are subject to waveform modulation while they travel down axons or dendrites. The action potential waveform can be modulated by neuron geometry, local alterations in the ion conductance, and other biophysical properties including neurotransmitter release.Sasaki, T., Matsuki, N., Ikegaya, Y. 2011 Action-potential modulation during axonal conduction. Science 331 (6017), pp. 599–601.
See also Cellular neuroscience Neuron NeuroElectroDynamics
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