Figure 1. T cells influence brain function by regulating the activation status of local myeloid cells.
Top, In the T cell niche surrounding a healthy brain, T cells regulate meningeal macrophages, and possibly microglia, by the release of IL-4 and other pro-cognitive molecules. Resting microglia survey the brain parenchyma and support a healthy environment for brain development. Bottom, When T cells are absent, or malfunctioning, meningeal macrophages and microglia become activated and unleash pro-inflammatory molecules. This pro-inflammatory milieu is detrimental to normal brain function and may contribute to the developmental abnormalities in ASD.