I have been studying the neuroimmune interactions in the healthy and diseased CNS for twenty five years (since my graduate school). During my graduate work I discovered the role of naturally occurring regulatory T cells in regulation of the immune response after CNS injury. During my graduate and a short post-doctoral training, I also became interested in the role of the immune system in cognition and behavior and have never stopped working on this topic. I showed that immune deficient mice exhibit impaired cognitive function as assessed in spatial learning and memory tasks, and that this impairment is reversible upon injection of T cells from wild type mice. In 2006, we identified the role of T cells in maintenance of adult neurogenesis. These studies allowed me to develop my own scientific niche, namely studying the role of the immune system in maintenance of the healthy CNS. In my lab, we are continuing to concentrate on the roles of immunity in brain function. We identified IL-4 producing T cells in the meningeal spaces as major regulators of spatial learning and memory through their cognate receptor on neurons. We demonstrated the role of T cell derived IFNγ in regulating social behavior, again through signaling on neurons via their expressed IFNGR. More recently, we have identified another interesting population of meningeal immune cells, gamma/delta T cells, producing IL-17 and affecting anxiety behavior through neuronal IL-17R. In 2015 we have reported an unexpected presence of functional meningeal lymphatic vessels in the dura mater that drain macromolecules and immune cells from the CSF to the deep cervical lymph nodes.