HOXB8 and Anxiety: That c-fos expression is upregulated in neighboring neurons to optogenetically stimulated Hoxb8 microglia but not following optogenetic stimulation of both microglial subpopulations, lends independent support for the model that Hoxb8 and non-Hoxb8 microglia functioning in opposition to each other in regulating the levels of grooming and anxiety in mice.