Cortical Thickness Alterations Can Precede Amyloid Positivity

MONDAY, Aug. 24, 2026 (HealthDay News) — Alterations in cortical thickness can precede positron emission tomography (PET)-detectable amyloid positivity by several years, according to a study published online Aug. 19 in Nature Neuroscience.

James M. Roe, from the University of Oslo in Norway, and colleagues combined longitudinal magnetic resonance imaging (MRI) and amyloid-beta (Aβ) PET data from three cognitively healthy cohorts to examine cortical thickness trajectories in individuals who later converted to Aβ-positive status. MRI studies were acquired years before conversion.

The researchers found a thicker cortex and reduced cortical thinning in individuals who subsequently developed elevated Aβ, which was detectable up to seven years before conversion. After accounting for quantitative Aβ levels, many effects persisted, suggesting that some of the changes in cortical thickness may be partially independent of Aβ. Moderate spatial correspondence was seen for differences in cortical thickness and its change with Aβ deposition patterns; the timing of thickness changes tracked the progression of accumulation of Aβ.

“The most groundbreaking aspect of this study is that we found structural changes in the brain many years before the first signs of plaque buildup, which is considered to be the earliest sign of Alzheimer”s disease,” coauthor Anders M. Fjell, Ph.D., also from the University of Oslo, said in a statement. “These are cognitively well-functioning older individuals. What is unique here is that we have examined changes in brain structure in the years before the first scan revealed plaques.”

Some of the data used for this study were obtained from the Alzheimer”s Disease Neuroimaging Initiative, which is funded by biopharmaceutical companies; two authors disclosed ties to the pharmaceutical and medical technology industries.

Abstract/Full Text