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Que PASA? The posterior-anterior shift in aging
Simon W Davis1, Nancy A Dennis, Sander M Daselaar
1Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA.
Cerebral Cortex (New York, N.Y. : 1991)
|October 11, 2007
Summary
The posterior-anterior shift in aging (PASA) shows reduced brain activity in the back of the brain and increased activity in the front. This pattern is linked to cognitive compensation in older adults.
Area of Science:
- Neuroscience
- Cognitive Aging Research
- Functional Neuroimaging
Background:
- Cognitive aging studies consistently show reduced occipital activity and increased frontal activity.
- This posterior-anterior shift in aging (PASA) is often linked to functional compensation.
Purpose of the Study:
- To confirm PASA reflects aging, not task difficulty.
- To test the compensation hypothesis for PASA.
- To investigate if PASA applies to brain deactivations.
Main Methods:
- Functional magnetic resonance imaging (fMRI) was used.
- Young and older adults performed episodic retrieval and visual perceptual tasks.
- Age-related brain activity changes common to both tasks were analyzed.
Main Results:
- PASA was observed across tasks and confidence levels, independent of performance matching, refuting a difficulty account.
- Increased frontal activity correlated positively with performance and negatively with occipital decreases, supporting compensation.
- PASA generalized to deactivations, with reduced posterior midline and increased medial frontal deactivations in older adults.
Conclusions:
- The findings validate the existence, function, and generalizability of PASA.
- PASA is crucial for understanding the cognitive neuroscience of aging.
- The study supports the compensatory role of frontal activity in cognitive aging.
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