Age differences in the functional architecture of the human brain
Roni Setton1, Laetitia Mwilambwe-Tshilobo1, Manesh Girn1
1Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.
Cerebral Cortex (New York, N.Y. : 1991)
|March 1, 2022
Summary
Brain function changes with age, showing global dedifferentiation and specific network alterations in older adults. These findings emphasize multiscale analysis for understanding brain aging.
Area of Science:
- Neuroscience
- Cognitive Aging
- Brain Imaging
Background:
- Brain functional organization shifts significantly in older adulthood.
- Age-related changes occur across multiple spatial scales, from global network modularity to specific patterns of dedifferentiation.
- The exact nature of brain dedifferentiation with age (global vs. experience-dependent) remains unclear.
Purpose of the Study:
- To investigate brain functional organization changes across the lifespan using a multimethod approach.
- To examine dedifferentiation at multiple spatial scales, from global to microscale network levels.
- To characterize the architecture of functional brain aging.
Main Methods:
- Multi-echo resting-state functional magnetic resonance imaging (ME-fMRI) in healthy younger and older adults.
- Precision functional mapping using individual-sensitive cortical parcellation.
- Gradient mapping and multivariate functional connectivity analyses to assess network differences at macro- and micro-scales.
Main Results:
- Older adults exhibited lower Blood-Oxygen-Level-Dependent (BOLD) signal dimensionality, indicating global network dedifferentiation.
- While overall gradients were age-invariant, discrete, network-specific dedifferentiation patterns were observed.
- Specific networks showed altered integration: visual and somatosensory regions became more integrated; default and frontoparietal control networks showed increased connectivity; dorsal attention network integrated more with heteromodal regions.
Conclusions:
- Brain aging is characterized by both global and network-specific functional alterations.
- Multiscale and multimethod approaches are crucial for a comprehensive understanding of functional brain aging.
- Findings reveal distinct patterns of network reorganization contributing to cognitive changes in older adulthood.
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