Properties of cortical axons for energy efficient cortical action potentials
© Yu; licensee BioMed Central Ltd. 2012
Published: 16 July 2012
Then we studied the energy efficiency for action potential initiation and propagation in unmyelinated and myelinated axons. Comparing to a point model, Na+ entry ratio (SER) increases for action potential initiation in the unmyelinated axon. This is because that an additional amount of INa is required to flow into neighborhood axon compartment when AP is propagated on the axon. This axial Na+ current results in a rapid rising phase of membrane potential, triggering a large amount of local Na+ influx for local action potential generation. Therefore, this axial Na+ current saves energy for action potential generation in the neighborhood compartment during AP propagation. Compared to the unmyelinated axon, spike propagation in a myelinated axon saves energy extensively for AP propagation.
In summing, the energy cost for action potential initiation and propagation in cortical axons is not only ionic channel dependent, but also axonal property dependent.
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