Microglia
DEMikroglia
Microglia are your brain's resident immune cells. They come from yolk-sac precursors that colonize the brain early in embryo development, and they renew themselves without help from blood monocytes. In their healthy state, they constantly survey the brain with branching arms, pruning synapses, clearing dead-cell debris, and releasing nerve-supporting factors. With age, they shift toward a 'primed' or worn-out (dystrophic) state. They change shape, clean up less well, and overreact to new triggers, which fuels neuroinflammation. In Alzheimer's, genetic hits in microglia genes (like TREM2, CR1, and BIN1) strongly implicate them in the disease. That puts microglia in a dual role: both sensors of amyloid and tau, and active drivers of how the disease progresses.
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