Fig. 3. Characterization of a wide dynamic range (WDR) neuron. (  A ) Response of the neuron to brush and pinch of the somatic field. (  B ) Responses to von Frey filaments; the threshold was 30 mN, and greater filament strengths produced increased cell activity. (  C ) von Frey filament thresholds of 29 WDR neurons. (  D ) Digitized oscilloscope trace of the action potentials during pinch. (  E ) Drawing depicting the somatic field; the  gray area is the region responding to pinch. The  black dot represents the site of application of the von Frey filaments in (  B ). (  F ) Summary of the average peak increase in action potential rate produced by application of von Frey filaments to 29 WDR neurons.