Fig. 1
From: Brain reserve contributes to distinguishing preclinical Alzheimer’s stages 1 and 2
Hypothetical volumes of memory regions in amyloid-negative (A−) asymptomatic healthy controls, A− subjective cognitive decline (SCDs), stages 1 and 2. According to a continuum model, volumes should be gradually smaller from A− asymptomatic to 2. According to a brain reserve model, stage 1 should have higher volumes than A− asymptomatic (“higher than expected”), while stage 2 should show the expected decrease. The A− SCD group serves as a control that any volume differences between stages 1 and 2 are not solely attributable to the presence of memory complaints