Researchers at the Laboratoire bordelais de recherche en informatique (LaBRI) (CNRS/Bordeaux INP/Université de Bordeaux), at the Aquitaine Institute for Cognitive and Integrative Neuroscience (CNRS/Université de Bordeaux/EPHE) and the University of Valencia (Spain) created a model which traces brain changes and activity over an entire life span using a massive set of over 4,000 MRI scans processed with the volBrain platform.
Prior to this, scientists did not have images covering every period of an Alzheimer patient’s life. Researchers suggested modelling the changes generally seen in the volumes of different structures using a vast quantity of samples in order to pinpoint where healthy brains diverged from diseased ones over time.
Hippocampus And Amygdala Atrophy
Based on MRI scans from 2,944 healthy control subjects between the ages of 9 months to 94 years old, the team developed a ‘normal’ model of average brain changes, which they compared to a pathological model based on MRIs from 1,385 Alzheimer’s patients aged over 55 and 1,877 young control subjects.
Their results show an early divergence between the pathological models and the normal trajectory of ageing of the hippocampus before age 40, and of the amygdala around age 40. Both of these structures suffer atrophy in the presence of Alzheimer’s disease.
[caption id=“attachment_98531” align=“aligncenter” width=“680”] Models based on relative volumes (% total intracranial volume) for brain cortical and subcortical structures across the entire lifespan.
Credit: P. Coupé, et al. CC-BY[/caption]
Also evident is an early enlargement, in patients with the disease, of an internal cavity in the brain known as the lateral ventricle. This enlargement is part of the ageing process in normal subjects too, however, thus limiting the pertinence of this measurement in subjects of an advanced age, and reaffirming the usefulness of studying biomarkers across an entire life span.
Pierrick Coupé, José Vicente Manjón, Enrique Lanuza & Gwenaelle Catheline Lifespan Changes of the Human Brain In Alzheimer’s Disease Scientific Reports volume 9, Article number: 3998 (2019)
Top Image: NIH NICHD