Biomarkers.

Background: The brain undergoes structural changes during aging, such as gray matter loss, enlarged ventricles, and sulcal widening. However, previous studies have primarily investigated these changes in isolation, without describing the complex spatial relationships between overall brain shape and regions. Here, we tested how gradients of expansion and compression of the global shape of the brain as well as between homologous brain regions across hemispheres are affected by age, and whether these changes further contribute to clinical impairment and cognitive deficits in older adults.

Amyloid-β deposition in basal frontotemporal cortex is associated with selective disruption of temporal mnemonic discrimination.

Cerebral amyloid-beta (Aβ) accumulation, a hallmark pathology of Alzheimer's disease (AD), precedes clinical impairment by two to three decades. However, it is unclear whether Aβ contributes to subtle memory deficits observed during the preclinical stage. The heterogenous emergence of Aβ deposition may selectively impact certain memory domains, which rely on distinct underlying neural circuits.

Age-related constraints on the spatial geometry of the brain.

Age-related structural brain changes may be better captured by assessing complex spatial geometric differences rather than isolated changes to individual regions. We applied a novel analytic method to quantify age-related changes to the spatial anatomy of the brain by measuring expansion and compression of global brain shape and the distance between cross-hemisphere homologous regions. To test how global brain shape and regional distances are affected by aging, we analyzed 2,603 structural MRIs (range: 30-97 years).