Fig 4. Noise induces acceleration of action potential kinetics in DRG neurons.

(A) Superimposed action potentials from a DRG neuron with monotonic decay in response to step (grey) and step + noise (black) stimuli. Threshold for spike and peak are reached earlier in the presence of noise. (B) Phase plots of the same spikes showing that inflection point (threshold for spike) is almost superimposed in the two curves. (C) With noise, depolarisation to threshold is faster in all neurons tested. Bar graph represents average slope of membrane potential (measured by linear fit) in the region indicated by the arrows in A, with and without noise. Lines represent values in individual neurons (n = 23, P < 0.00005 by paired Student's t test).