On day 55 of #LMB365 we bring you brown stained microglia by Jennifer Macdonald from the lab of Michel Goedert @MichelGoed in the Neurobiology Division. Microglia are cells within the brain and spinal cord whose role is to survey their environment and eat up cellular debris or dead neurons. They are incredibly dynamic and respond to changes by adopting different states. This picture is that of a brain in which many clumps or aggregates consisting of a protein named tau, though not made visible here, are present. Some argue the state adopted by microglia plays a crucial role in the outcome of a variety of neurodegenerative diseases, including tauopathies, diseases in which tau protein forms clumps. Here an array of morphologies can be seen, probably reflecting the various states microglia adopt. Are all these microglia in states harmful to neurons or are some of these in a state that is helping neurons clear or cope with tau aggregates?