Fig. 2. Examples of electrophysiological alterations in neuronal somata after chronic compression of dorsal root ganglion (CCD) and CCD treatment followed by vitamin B1 treatment  in vitro in intact dorsal root ganglion (DRG).  A : Responses recorded with sharp electrodes for intracellular recordings using conventional bridge-balance techniques. Only one of the hyperpolarizing and depolarizing 50-ms pulses (  below ) and responses (  above ) are illustrated in each case.  B : Discharge patterns of the DRG neurons tested with 1-s pulses at 2.5 × the 50-ms threshold current. Responses are from the same neurons as illustrated in panel  A .  C and  D : Examples of spontaneous activity displayed by DRG neurons (  C , medium-sized neuron;  D , large-sized neuron from intact CCD DRG).