Influence of functional connectivity and structural MRI measures on episodic memory
Jing He1, Owen Carmichael, Evan Fletcher
1Imaging of Dementia and Aging (IDeA) Laboratory, Department of Neurology, University of California, Davis, Davis, CA 95618, USA. jing.he@ucdmc.ucdavis.edu
Neurobiology of Aging
|January 31, 2012
Summary
Brain changes like gray matter atrophy and white matter injury impact memory in older adults. Enhanced brain connectivity may compensate for these changes, preserving episodic memory performance.
Area of Science:
- Neuroscience
- Cognitive Aging Research
- Neuroimaging
Background:
- Age-related memory decline results from brain structural and functional changes.
- The specific roles of gray matter atrophy, white matter injury, and altered functional connectivity in memory decline are not fully understood.
Purpose of the Study:
- To investigate the independent contributions of gray matter volume, white matter hyperintensities, and functional connectivity to episodic memory performance in cognitively normal older adults.
- To explore how brain structural changes interact with functional connectivity in relation to memory.
Main Methods:
- Utilized magnetic resonance imaging (MRI) to assess gray matter (GM) volume and white matter hyperintensity (WMH) volumes.
- Employed blood oxygen level-dependent (BOLD) functional MRI to measure functional connectivity within the default mode network.
- Analyzed data from 76 cognitively normal older adults.
Main Results:
- Gray matter volume, white matter hyperintensities, and functional connectivity between the medial prefrontal cortex and left inferior parietal cortex (MPF_LIP) were independently associated with episodic memory performance.
- In individuals with lower gray matter volume, increased MPF_LIP connectivity correlated with better memory.
- This association between connectivity and memory was not observed in individuals with higher gray matter volume.
Conclusions:
- Brain structure (GM, WMH) and function (connectivity) independently influence episodic memory in aging.
- The findings highlight the heterogeneous nature of brain-behavior relationships in cognitive aging.
- Resting-state functional connectivity may play a compensatory role against neuronal injury, particularly in individuals with significant brain atrophy.
