In the vehicle-treated mice, there was no observable difference in cortical pERK1/2 expression but pERK1/2 was reduced in AOM-treated ICV saline-infused mice compared to the vehicle-treated groups and this reduction of pERK1/2 expression was reversed by ICV soluble fractalkine infusion (Fig. 4a). Here, CX3CL1 is linked to infectious otitis media.