Microglia and other brain-resident macrophages are central regulators of brain aging and age-associated neurodegenerative diseases. As our understanding of their functional heterogeneity continues to expand, so does the need for robust, reproducible, and accessible methodologies to study these cells across multiple scales, from computational and bioinformatic analyses to in vivo functional assays.

This Topical Collection will bring together methodologies for investigating the roles of microglia and other central nervous system macrophages in healthy aging and age-related neurodegenerative diseases, including dementia, Alzheimer's disease, and Parkinson's disease. We welcome contributions covering the following areas:

1. Bioinformatic and computational approaches, including single-cell and single-nucleus transcriptomic analysis, spatial transcriptomics, and comparative aging trajectory modeling.
2. In vitro and ex vivo functional assays, including phagocytosis assays, cytokine profiling, and quantitative morphological analysis.
3. Microglia and brain-associated macrophage culture methods, including cell isolation, in vitro culture, co-culture with other cell types, and differentiation from peripheral blood mononuclear cells (PBMCs) and pluripotent stem cells.
4. In vivo methodologies, including microglial depletion and repopulation models, bone marrow transplantation approaches, and imaging-based assessment of microglial dynamics in the aging or diseased brain.

We welcome a range of article types, including literature reviews synthesizing recent advances in microglia research related to aging and neurodegeneration, rapid communications describing novel or emerging techniques, and methods articles spanning the bioinformatic-to-in vivo spectrum outlined above.

By bringing together reproducible protocols for studying microglia and brain-resident macrophages in aging and neurodegeneration, this collection aims to serve as a practical resource for researchers entering the field and for established investigators seeking to expand their methodological toolkit.