Ultrastructural Analyses of Microglial Interactions with Synapses.

Immunohistochemical electron microscopy (EM) allows the identification of microglial cell bodies and processes, which are otherwise difficult to recognize based on their ultrastructural features. The technique has been essential in defining, at high spatial resolution, microglial interactions with neurons and synapses, thus providing, among other discoveries, important insights into their roles in synaptic pruning and stripping. In this protocol, we describe the preparation of mouse brain tissue for EM, the immunocytochemical staining against ionized calcium binding adaptor molecule 1, the imaging of microglial cell bodies and processes, and the analysis of microglial relationships with the synaptic neuropil.