Toll Like Receptor signalling as a mediator of sex differences in pain, opioid and alcohol action. Brain immunology will be examined in this project to see if the signalling of a receptor called Toll Like Receptor 4 can explain sex differences in pain, and the action of pain killers and alcohol. These findings will have significant implications on the understanding of male and female brains, and will assist in the design of new drugs to treat brain and spinal cord diseases.