A) Ratemeters showing spontaneous and thermal withdrawal-related activity of a typical ON-cell and OFF-cell before and after CFA injection.
B) CFA but not saline injection increased spontaneous activity of ON-cells (Wilcoxon’s signed ranks test, CFA: p = 0.019, n = 11; Saline: p = 0.96, n = 6) and decreased that of OFF-cells (CFA: p = 0.016, n = 7; Saline: p = 0.37, n = 5). NEUTRAL cell spontaneous activity was unaffected by either treatment (CFA: p = 0.37, n = 10; Saline: p = 0.99, n = 6). BL: baseline.
C) Firing associated with noxious stimulation trials was generally unaffected by CFA. However, the reflex-related OFF-cell inhibition from thermal stimulation was significantly enhanced after CFA injection.