CHAT and Alzheimer disease: We also characterized the effects of xenon on septal cholinergic neurons, that is, a subpopulation of forebrain neurons particularly vulnerable to degeneration in the context of AD.31,32 Unexpectedly, cholinergic neurons identified by immunofluorescence detection of choline acetyltransferase (ChAT) exhibited much larger cell bodies when exposed transiently to 75% xenon between 12 and 16 days in vitro (DIV) (Figure 5a, left panel; Figure 5b).