A new study shows that a combination of inflammation and hypoxia activates microglia in a way that persistently weakens the connection between neurons, contributing to brain damage in conditions such as stroke and Alzheimer's disease.

http://www.eurekalert.org/pub_releases/2014-03/uobc-scb031214.php

[3625] Zhang, J., Malik A., Choi H. B., Ko R. W. Y., Dissing-Olesen L., & MacVicar B. A.
(2014).  Microglial CR3 Activation Triggers Long-Term Synaptic Depression in the Hippocampus via NADPH Oxidase.
Neuron. 82(1), 195 - 207.