Time course of changes in cold sensitivity plate responses after bilateral ligation surgery, tested at 0.3°C. Total number of hindpaw lifts. bCCI rats had increased number of hindpaw lift events compared to sham operated animals. Results were highly significant (p < 0.001; F = 874.58; DF = 1; two-way ANOVA) during the entire testing period. (B) Total active duration of hindpaw lifts. More activity demonstrates presence of increased nocifensive reflex responding to cold. bCCI rats showed a highly significant difference (p < 0.001; F = 510.26; df = 1; two-way ANOVA) from day 9 of testing. (C) First hindpaw lift to cold stimuli. bCCI rats showed a highly significant difference (p < 0.001; F = 970.51; df = 1; two-way ANOVA) throughout the testing period. (D) Total time spent lifting per 600 second trial on a subgroup of 4 rats tested up to 90 day post-bCCI or sham surgery. bCCI rats showed increased time spent lifting compared to shams that persisted for the duration of testing (90 days).