“This research provides evidence that, in cognitively normal adults, increased iron content and beta-amyloid plaque coincide with reduced entorhinal cortex volume,” Rodrigue said. “Beta-amyloid alone did not reveal these associations — only the joint effect of iron and beta-amyloid. “That seems to be the role of the entorhinal cortex. “The applications of this type of work are not only for preclinical stages of AD, but also about healthy aging,” she said. “There’s a remarkable amount of neurological variance in healthy aging.