microglial activation
The process by which resident brain immune cells become inflammatory and phagocytic in response to CNS injury or disease.
Full Definition
Microglial activation refers to the transformation of resting microglia into an activated state characterized by morphological changes, proliferation, and altered gene expression. Activated microglia can adopt different phenotypes, from pro-inflammatory (M1-like) to anti-inflammatory/reparative (M2-like) states. This process is central to neuroinflammation and plays dual roles in neurological diseases—both contributing to tissue damage through inflammatory mediator release and supporting repair through debris clearance and growth factor production. Microglial activation can be visualized using PET imaging with specific tracers.
Usage
Usage note: Distinguish between beneficial and harmful aspects of activation in clinical contexts.
In Context
- "PET imaging revealed widespread microglial activation in the patient's brain." — Imaging report
- "The study examined microglial activation markers in post-mortem tissue." — Research methodology