Functional brain connectivity changes across the human life span: From fetal development to old age

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Cognitive Neuroscience

Background:

• Functional connectivity (FC) describes temporal correlations between brain areas.
• FC undergoes significant transformations throughout the human lifespan, from fetal development to advanced age.
• Understanding these changes is crucial for comprehending brain development and aging.

Purpose of the Study:

• To provide an overview of functional connectivity changes in the nonpathological brain across the entire lifespan.
• To describe the developmental trajectory of functional connectivity from fetal life to old age.
• To correlate these functional brain changes with cognitive and sensory function development and decline.

Main Methods:

• Review of existing literature on functional connectivity dynamics across the lifespan.
• Description of methodologies used to assess functional connectivity.
• Categorization of functional connectivity development into distinct life phases.

Main Results:

• FC development is characterized by four main phases: emergence of proto-networks (prenatal), network organization and integration (early childhood), refinement and increased integration (adolescence to early adulthood), and a shift towards decreased segregation and reorganization (middle age).
• Aging is associated with dedifferentiation processes, leading to less specialized functional connectivity and cognitive decline.
• These functional changes align with neuroanatomical development and deterioration patterns.

Conclusions:

• Functional connectivity exhibits distinct developmental phases throughout life, influencing cognitive abilities.
• Middle age represents a turning point, with a reversal of developmental trends in functional brain organization.
• Aging leads to dedifferentiation, impacting cognitive function, consistent with neuroanatomical aging models.