Does shrinking of the angular gyrus in the brain lead to cognitive decline as we get older? A new study by Human Brain Project scientists in Germany has revealed a clearer picture.
The angular gyrus is an area in the back of the brain, which is associated with cognitive functions like language and memory. It has been found to shrink in aging, which is suspected to play a role in the decline of cognitive functions as we get older. But it was not yet clear in how far this suspicion is true, as findings remained inconclusive.
Now, researchers at HBP partner University of Düsseldorf together with Forschungszentrum Juelich in Germany have taken a closer look. The team at the lab of Prof. Svenja Caspers focusses on changes in brain structure, function and connectivity during aging, including their variability between people.
In the microstructural Julich Brain Atlas on the HBP’s EBRAINS research infrastructure, the gyrus was previously revealed to be divided into two distinct regions, now named PGa and PGp.
Two distinct areas with different roles in aging
“These sub-areas may serve different functions, so that cognitive tests so far would have led to contradictory results about the activation profile of the angular gyrus,” says Christiane Jockwitz, lead author of the study.
On this basis, the team performed a deep analysis of the structural and functional characteristics of the two sub-areas in 500 older adults. This analysis included the volume and connectivity with other areas, as well as their associations with age, cognition and lifestyle. For this, the data of the German 1000BRAINS study was used, which investigates the variability of structure, function and connectivity in the aging brain in relation to environmental, lifestyle or genetic influencing factors in a large group of older adults.
Analyzing the two areas’ structural and functional connectivity at the group level revealed that each region is involved in different ways within the network architecture of the older adult brain. This result was further supported by distinct molecular and genetic patterns, derived from the Julich Brain Atlas on EBRAINS as well. These differences continued when each areas’ associations to age-related changes and cognitive ability as well as to lifestyle were profiled.
High degree of variability between brains
When the perspective was switched to the individual, the researchers found a high variability between subjects. “It should be emphasized that correlations found on the group level do not necessarily translate to the individual level” concludes Jockwitz. “General observations within the older adult population must therefore be considered with caution, especially when assessing and treating individual patients.”
The study thus highlights both the need to investigate the angular gyrus’ subdivisions as different entities rather than one macro-anatomical structure, and the high degree of variability that must be accounted for in exploring the aging brain.
C Jockwitz et al.: Characterization of the angular gyrus in an older adult population: a multimodal multilevel approach. Brain Structure and Function (2022)
HBP scientist Svenja Caspers uses big data to better understand why brains vary so much in across individuals, particularly during aging
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