Brain morphology links systemic inflammation to cognitive function in midlife adults

Area of Science:

• Neuroscience
• Cognitive Aging
• Inflammation Research

Background:

• Systemic inflammation is increasingly linked to cognitive decline in midlife.
• The neural mechanisms underlying this association, particularly through brain morphology, remain unclear.
• Understanding these links is crucial for identifying early risk factors for cognitive aging and dementia.

Purpose of the Study:

• To investigate whether cortical gray matter volume mediates the relationship between peripheral systemic inflammation and cognitive function in midlife adults.
• To explore the role of inflammation in cognitive aging and its association with brain morphology.

Main Methods:

• Assessed plasma levels of interleukin-6 (IL-6) and C-reactive protein (CRP) in 408 community volunteers (aged 30-54).
• Utilized structural neuroimaging (Freesurfer) to measure global and regional brain morphology, including cortical gray matter volume.
• Administered neuropsychological tests to assess various cognitive functions, including spatial reasoning, memory, verbal proficiency, and executive function.

Main Results:

• Higher levels of inflammation (IL-6, CRP) were associated with poorer performance across multiple cognitive domains.
• Inflammation correlated with reduced cortical gray and white matter volumes, hippocampal volume, and cortical surface area.
• Cortical gray matter volume partially mediated the association between inflammation and cognitive performance, with adiposity suggested as a potential source of inflammation.

Conclusions:

• Peripheral systemic inflammation is associated with both reduced brain morphology and impaired cognitive function in midlife adults.
• Brain morphology, specifically cortical gray matter volume, acts as a mediator in the link between inflammation and cognition.
• Adiposity may contribute to the inflammatory pathways that negatively impact brain structure and cognitive function.