Effects of ipsilateral or contralateral EA on pain sensation and affection in the formalin model. A, Either ipsilateral or contralateral EA significantly decreased the paw lifting time in the second phase of the formalin test. B, Contralateral but not ipsilateral EA reduced paw licking time in the second phase. C, ACC lesions reversed F-CPA, which was a significant decrease of the time spent in the formalin-paired compartment. D, ACC lesions significantly decreased CPA scores. E, F-CPA was reversed by either ipsilateral or contralateral EA. F, Either ipsilateral or contralateral EA significantly decreased CPA scores. * p < 0.05; ** p < 0.01; *** p < 0.005 compared with the formalin group (A, B, D and F) and between pre-conditioning and post-conditioning days (C and E). All data were presented as means ± SEM.