Pain signals to brain stem and brain ightly myelinate As fibres Large cell (through secondary To supraspinal ain-projection targets neurons Heavily DRG myelinated Aβ fibres Dorsal Small cell bodies Unmyelinated Fibres neurons Ventral Ventral projection fibres Pain signals to spinal cord (through primary afferents Normal acute pain Milligan et al 2009Milligan et al, 2009