I am recording extracellular action potential (EAP) in situ/in vivo from the sciatic nerve of rat in response to von Frey filament stimulation in the paw. I get spikes that seem to be multiples of single amplitude events. if I group the data in bins of increasing amplitude (I limited my measurements to 3) I see a shift from small to large amplitude as I increase the stimulus intensity but little change in frequency if I simply count the number of spikes per second for the duration of the given stimulus. I use Spike2 for both analysis and recording and the program does not have a way to either measure simple frequency or recognize overlapping events, While I am aware that axon diameter and distance of fibers from electrode can account for differences in spike amplitudes my gut feeling is that if you see multiples of single amplitude it is more likely that they are due to overlap of synchronously firing fibers. One simple question is what would be the ideal sampling rate for these experiments, when I increased to 25kHz I started getting strange looking waveforms. Secondly what would be the approach of automating the measurements of spike frequency? Thanks for the input!