CA1 and Alzheimer disease: Furthermore, studies are providing evidence for predominant Cornu Ammonis (CA‐1) and subiculum atrophy in MCI (Atienza et al., 2011) and AD (Frisoni et al., 2008; Wisse et al., 2014) suggesting that some parts of the hippocampus, and therefore, some mnemonic functions will be especially vulnerable.