Within the past few years, it has become recognized that the immune system communicates to the brain. Substances released from activated immune cells (cytokines) stimulate peripheral nerves, thereby signaling the brain and spinal cord that infection/inflammation has occurred. Additionally, peripheral infection/inflammation leads to de novo synthesis and release of cytokines within the brain and spinal cord. Thus, cytokines effect neural activation both peripherally and centrally. Through this communication pathway, cytokines such as interleukin-1, interleukin-6 and tumor necrosis factor...