Functional Connectivity of Successful Picture-Naming: Age-Specific Organization and the Effect of Engaging in Stimulating Activities

Abstract

Aging is a lifelong process that starts at birth. Throughout the course of their life, individuals are exposed to various levels of stimulating activities. A higher level of engagement in such activities is suspected to protect against the normal course of cognitive aging or the cognitive manifestations of age-related brain diseases. However, the exact mechanism underlying such protective action remains unclear. The concept of the neurocognitive reserve was introduced to refer to the hypothesis that engagement in stimulating activities shapes brain structure and function, thus indirectly allowing for better preserved cognitive abilities. Although it is known that word production is among the best-preserved cognitive abilities in aging, the underlying neurofunctional mechanisms that allow this relative preservation are still unknown, and it is still unclear how engagement in stimulating activities affects these processes. The objective of this study is to describe the brain functional connectivity patterns associated with picture-naming abilities in younger and older adults with varying levels of engagement in stimulating activities, as a proxy for neurocognitive reserve. A mediation analysis was applied to determine whether the association between reserve proxies and naming accuracy is dependent on task FC. Results show that naming accuracy depends on the posterior cingulate cortex (PCC) functional decoupling in both younger and older adults but through different pathways. While high-performing older adults rely on the asynchronization of this area from motor speech regions' activity, the best-performing younger adults rely on the functional decoupling with language-related regions. Mediation analysis reveals that the PCC decoupling mediates the relationship between the level of engagement in stimulating activities and naming accuracy in younger adults, but not in older adults. These findings suggest that reserve-related mechanisms may be more critical for naming in early adult life, while older adults' neurofunctional organization may benefit more from a lifetime of acquired knowledge.

Decoding bilingualism from resting‐state oscillatory network organization

“…These findings are consistent with previous evidence indicating that higher rates of vocabulary learning correlate with beta power modulations 81 . Additionally, better performance in picture‐naming negatively correlates with rsFC in the DMN, 82,83 as indexed here by delta dynamics. Furthermore, in the bilingual domain, beta 20,21 and delta 84 connectivity have been shown to correlate with L2 learning proficiency.…”

Age differences in semantic network structure: Acquiring knowledge shapes semantic memory.

“…These stimuli have been used successfully in the past to create semantic memory networks across several studies, labs, and languages (Benedek et al, 2017;He et al, 2021;Ovando-Tellez et al, 2022). Prior work in the aging literature has shown that during picture naming word retrieval, older adults have lower accuracy for low-frequency items compared to younger adults (Burke et al, 1991;Ferre et al, 2020;Gertel et al, 2020), which suggests that even larger agerelated differences may be found with less frequent words. Future studies should expand the breadth of cue words to include lower frequency items that may lie along the periphery of the semantic network and may reveal greater age-related differences.…”

Modulations of static and dynamic functional connectivity among brain networks by electroacupuncture in post-stroke aphasia

“…From now on, we shall refer to components as “networks” and we will identify components by referring to their label (e.g., DMN); component descriptions are listed in Supplementary Table 1 . For the spatial map, we examined how the PSA-related network structure differed between the two groups using a voxel-wise F-test (group main effect), as in previous studies ( 36 ).…”