Modulation of the Time Relation of Action Potential Impulses Propagating Along an Axon

Action potentials are successively evoked on a squid giant axon by a Gaussian impulse train which has a white spectral density for low frequencies. The time relations of the response impulses are different from those of the stimuli because of the refractory period of the axon which cuts off too short pulse intervals and modifies the traveling velocities of the action potentials. As a result, the action potential sequence acquires l/f component on the low frequency tail of the power spectral density. It is quite probable that the biological information which is carried by the time relations of the action potentials is disturbed by 1/f noise. The observed result is compared with the result of computer simulation.