Pattern and dynamic changes of integer multiples in spontaneous discharge of injured dorsal root ganglion neurons

For the purpose of the present investigation, spontaneous discharges of dorsal root ganglion (DRG) neurons of the rats, which had undergone 3-10 days' chronic compression, were studied. It was found that the interspike interval (ISI) of 17 out of 156 fibers had integer multiples temporal rhythm pattern, in which all the ISI were integer multiples of a basic ISI and a return map of their ISI could be constructed as a crystal grid structure. This temporal pattern could be modified by Na+ channel and K+ channel on their membranes. These data indicated the presence of some irregular discharge trains with their intrinsic regularity.