Finally, although there is ample reason to think of SAI as a good marker of cholinergic activity (SAI is reduced by scopolamine in healthy adults (Di Lazzaro et al., 2000), it is decreased in patient populations with deficient cholinergic activity (e.g., AD, Lewy Body disease, vascular dementia; Di Lazzaro et al., 2007b, 2008a), and it can be rescued by acetylcholinesterase inhibitors in AD patients (Di Lazzaro et al., 2002), SAI may also be modulated at the cortical level in part by GABAA receptors. This evidence concerns the gene ACHE and Alzheimer disease.