pERK-LI neurons and NeuN-LI neurons in the NTS (A, B and C: 10 mm capsaicin injection to the whisker pad skin; D, E and F: 10 mm capsaicin injection to the lingual muscle), Vc (G, H and I: 10 mm capsaicin injection to the whisker pad skin) and Pa5 (J, K and L: 10 mm capsaicin injection to the lingual muscle). M, time course change in the number of pERK-LI neurons in the NTS following capsaicin injection to the whisker pad skin. *P < 0.05.