Decreased Efficiency of Between-Network Dynamics During Early Memory Consolidation With Aging

Abstract

Aging is associated with memory decline and progressive disabilities in the activities of daily living. These deficits have a significant impact on the quality of life of the aging population and lead to a tremendous burden on societies and health care systems. Understanding the mechanisms underlying aging-related memory decline is likely to inform the development of compensatory strategies promoting independence in old age. Research on aging-related memory decline has mainly focused on encoding and retrieval. However, some findings suggest that memory deficits may at least partly be due to impaired consolidation. To date, it remains elusive whether aging-related memory decline results from defective consolidation. This study examined age effects on consolidation-related neural mechanisms and their susceptibility to interference using functional magnetic resonance imaging data from 13 younger (20–30 years, 8 female) and 16 older (49–75 years, 5 female) healthy participants. fMRI was performed before and during a memory paradigm comprised of encoding, consolidation, and retrieval phases. Consolidation was variously challenged: (1) control (no manipulation), (2) interference (repeated stimulus presentation with interfering information), and (3) reminder condition (repeated presentation without interfering information). We analyzed the fractional amplitude of low-frequency fluctuations (fALFF) to compare brain activity changes from pre- to post-encoding rest. In the control condition, fALFF was decreased in the left supramarginal gyrus, right middle temporal gyrus, and left precuneus but increased in parts of the occipital and inferior temporal cortex. Connectivity analyses between fALFF-derived seeds and network ROIs revealed an aging-related decrease in the efficiency of functional connectivity (FC) within the ventral stream network and between salience, default mode, and central executive networks during consolidation. Moreover, our results indicate increased interference susceptibility in older individuals with dynamics between salience and default mode networks as a neurophysiological correlate. Conclusively, aging-related memory decline is partly caused by inefficient consolidation. Memory consolidation requires a complex interplay between large-scale brain networks, which qualitatively decreases with age.

The formation of episodic autobiographical memory is predicted by mental imagery, self-reference, and anticipated details

“…In the present study, the decline of the memory score over the one-month time interval depended on the age of the participants. The influence of age is consistent with previous findings concerning EAM [see notably Faßbender et al (2022), Mair et al (2021), Sander et al (2021, Armson et al (2017), Martinelli et al (2013a), Piolino et al (2006)] as well as for the memory of new naturalistic events (Plancher et al, 2010;Abichou et al, 2019). Nevertheless, independently of the participants' age, we found a decline of the subjective self-rated scales over time (e.g., remembering, first-person perspective, reliving details, vividness), which is consistent with previous literature, in particular regarding the recency effect of the EAM retention curve as first described by Rubin (1982) and further experimentally confirmed by Piolino et al (2002) for instance.…”

Effects of hippocampal noninvasive theta-burst stimulation on consolidation of associative memory in healthy older adults

“…Certain memories were shown to be preferentially consolidated based on their characteristics 66 and the level of the encoding 67,68 , poorly encoded memories being prioritised for consolidation during sleep 66 . These considerations could be especially relevant if the participants present inefficient memory consolidation 69 due to age-related structural and functional alterations 70 . In line with this hypothesis, age-related impairments were demonstrated to particularly emerge in poorly encoded memories before sleep 71 , whilst no difference was found with respect to young subjects for strong memory representations.…”

Neuropsychological, plasma marker, and functional connectivity changes in Alzheimer’s disease patients infected with COVID-19

“…Specifically, there was a decline in local coherence in the aMTG and global correlation in the precuneus and MPFC. The aMTG is known for its critical involvement in memory (Jang et al, 2017;Fassbender et al, 2022) and language (Binder et al, 2011;Sugimoto et al, 2023), and it is associated with AD biomarkers (Jiang et al, 2016). The precuneus and MPFC are crucial regions of the defaultmode network and serve as hubs of the whole brain (Liang et al, 2013).…”