Age-Related Changes in Episodic Processing of Scenes: A Functional Activation and Connectivity Study

Area of Science:

• Neuroscience
• Cognitive Aging
• Neuroimaging

Background:

• The posterior-to-anterior shift in aging (PASA) is a proposed compensatory mechanism for cognitive demands in older adults.
• Empirical evidence for PASA in the inferior frontal gyrus (IFG), hippocampus, and parahippocampus is limited.

Purpose of the Study:

• To investigate age-related changes in brain activation and functional connectivity within the IFG, hippocampus, and parahippocampus.
• To examine the PASA effect in relation to cognitive performance in older and younger adults.
• To assess neural correlates of novelty and relational processing in aging.

Main Methods:

• Functional MRI (3-Tesla) was used to scan 33 older and 48 young adults during scene processing tasks.
• Analyses included functional activation and connectivity within key brain regions (IFG, hippocampus, parahippocampus).
• Participants were categorized as low/high-performing older adults and young adults.

Main Results:

• Significant parahippocampal activation was observed in both high-performing older and young adults.
• Younger adults exhibited greater IFG and parahippocampal activation than older adults, particularly for relational processing.
• Functional connectivity patterns, including within the medial temporal lobe and IFG-hippocampal/parahippocampal networks, partially supported the PASA effect.

Conclusions:

• The findings provide partial support for the PASA model, suggesting age-related differences in neural activation and connectivity.
• The study highlights the role of the IFG, hippocampus, and parahippocampus in cognitive compensation during aging.
• Neural mechanisms underlying performance differences between younger and older adults, and among older adults themselves, were partially elucidated.