Figure 3

Background activities (A) and afterdischarges (B) and mechanical responses (C and D) of Aδ-units to pressure, brushing or pinching of the receptive fields. Aa and Ba: IAN fibers in naive rats, Ab and Bb: background activity (Ab) and afterdischarge (Bb) of IAN fibers with receptive fields at 14 days after IAN transection, Ac: background activity of the IAN fiber without receptive field at 14 days after IAN transection, Ad and Bc: mean background activities and afterdischarges in naive, IAN-transected rats without behavioral changes and IAN-transected rats, respectively. Note that background activities and afterdischarges of A-units in IAN-transected rats showed significantly higher firing frequency than those of naive rats. C: typical mechanical responses in naive and IAN-transected rats. D: mean mechanical responses of A-units in naive and IAN-transected rats. Note that A-units showed significantly higher responses to non-noxious and noxious mechanical stimulation and also IAN-transected rats without behavioral changes showed any changes in spike frequency. -behav.change: IAN-transected rats without behavioral changes after IAN transection, +behav.change: IAN-transected rats which showed mechano-allodynia like behavior after IAN transection. RF+: area of receptive field can be defined by mechanical simulation to face. RF-: area of receptive field cannot be defined by mechanical simulation to face. * p < 0.05 (vs. naive)