The rapid decline in glial reactivation markers from the PART to the AD groups (Fig. 3D), particularly those associated with Mic (e.g., S100A9, C1QB, P2RY12), likely contributes to the decreased estimated proportions of these glial cell types in the CA1 region in AD, which may in turn explain the relative increase in Exc proportions in the comparison between AD and PART. Here, S100A9 is linked to Alzheimer disease.