Structural and Metabolic Correlates of Episodic Memory in Relation to the Depth of Encoding in Normal Aging

Abstract

This study set out to establish the relationship between changes in episodic memory retrieval in normal aging on the one hand and gray matter volume and (18)FDG uptake on the other. Structural MRI, resting-state (18)FDG-PET, and an episodic memory task manipulating the depth of encoding and the retention interval were administered to 46 healthy subjects divided into three groups according to their age (young, middle-aged, and elderly adults). Memory decline was found not to be linear in the course of normal aging: Whatever the retention interval, the retrieval of shallowly encoded words was impaired in both the middle-aged and the elderly, whereas the retrieval of deeply encoded words only declined in the elderly. In middle-aged and elderly subjects, the reduced performance in the shallow encoding condition was mainly related to posterior mediotemporal volume and metabolism. By contrast, the impaired retrieval of deeply encoded words in the elderly group was mainly related to frontal and parietal regions, suggesting the adoption of inefficient strategic processes.

Task-dependent Activity and Connectivity Predict Episodic Memory Network-based Responses to Brain Stimulation in Healthy Aging

“…That is, different LoP at encoding, such as semantic or perceptual analysis of the incoming information, result in more durable traces, therefore affecting the probability of a successful retrieval[34,35]. Although there is some evidence of age affecting LoP[36–38], this phenomenon has not been thoroughly investigated in aging. Importantly, it seems that if appropriate support is given during encoding phases (i.e.…”

Neuroanatomical Correlates of Cognitive Performance in Late Life

“…Recently developed techniques can obtain measures of grey matter (GM) volume and cortical thickness at the voxel level and permit the correlation study of cognitive function with any brain region, precluding the need for a priori hypotheses. A number of studies have examined the neuroanatomical correlates of cognitive performance using voxel-based measures, such as cortical thickness or GM volume, in healthy adults at different ages [3,7,8]. …”

Structural brain correlates of associative memory in older adults

“…One study by Zamboni et al (2013) found a link between HC volume, but not PFC volume, and performance in a visuospatial associative memory task in older adults. However, contrary to the present study, Zamboni and colleagues used incidental learning conditions (see also Kalpouzos et al, 2009). The HC is known for its pivotal role in rapidly forming associations between relational information in long-term memory (Eichenbaum, 2002;Olsen et al, 2012).…”

“…Structural MRI studies are less conclusive. Equivocal findings have been observed regarding the association between hippocampal volume and item memory (Hackert et al, 2002;Kalpouzos et al, 2009;Köhler et al, 1998;Rosen et al, 2003; for a review see Van Petten, 2004). Structural studies investigating associative memory are generally less common.…”