Olivier, J. M. | Search bioRxiv

bioRxiv2025

Moderating effects of cortical thickness, volume, and memory performance on age differences in neural reinstatement of scene information

The strength of neural reinstatement, a correlate of episodic memory retrieval, reportedly reflects the amount and fidelity of mnemonic content and is weaker in older than younger adults, especially for scene memoranda. Based on evidence that age-related declines in cortical thickness and volume contribute to age-related cognitive decline, we analyzed fMRI data acquired from healthy young and older adults to examine relationships between cortical thickness, cortical volume, age, and scene-related reinstatement in three cortical regions implicated in scene processing: the parahippocampal place area (PPA), medial place area (MPA), and occipital place area (OPA). A reinstatement index was estimated from fMRI data collected during tests of source memory for scene images, and multiple regression analyses were employed to examine the effects of the variables of interest on scene reinstatement. There were robust age differences in reinstatement, cortical thickness, and cortical volume. In the PPA and MPA, cortical volume fully mediated the effects of age on reinstatement. Additionally, PPA reinstatement strength predicted source memory performance independently of cortical volume or age. These findings suggest that age differences in scene reinstatement are mediated by cortical volume and that memory performance and cortical volume are associated with unique components of variance in reinstatement strength.

neuroscience↗

bioRxiv2025

Effects of age in the strategic control of recollected content as reflected by modulation of scene reinstatement

A previous study employing fMRI measures of retrieval-related cortical reinstatement reported that young, but not older, adults employ retrieval gating to attenuate aspects of an episodic memory that are irrelevant to the retrieval goal. We examined whether the weak memories of the older adults in that study rendered goal-irrelevant memories insufficiently intrusive to motivate retrieval gating. Young and older participants studied words superimposed on rural or urban scenes, or on pixelated backgrounds. To strengthen memory for background information, word-image pairs were studied twice, initially centrally, and then in one of three locations. During scanning, one retrieval test probed memory for the test words studied backgrounds and another test assessed memory for their location. Background memory performance was markedly higher than in the prior study. Retrieval gating was examined in two scene-selective regions of interest, the parahippocampal place area (PPA) and the medial place area (MPA). In the background task, robust retrieval-related scene reinstatement effects were identified in both age groups. These effects were attenuated ( gated) in the location task in the young age group only, replicating the prior finding. The results did not differ when the two groups were sub-sampled to match strength of scene reinstatement when scene information was goal relevant. The findings indicate that older adults failure to gate goal-irrelevant scene information does not reflect age differences in memory strength and may instead reflect an age-related decline in top-down inhibitory control.

neuroscience↗