Right Lateralized Brain Reserve Offsets Age-Related Deficits in Ignoring Distraction

Abstract

Age-related deterioration of attention decreases the ability to stay focused on the task at hand due to less efficient selection of relevant information and increased distractibility in the face of irrelevant, but salient stimuli. While older (compared with younger) adults may have difficulty suppressing salient distractors, the extent of these challenges differs vastly across individuals. Cognitive reserve measured by proxies of cognitively enriching life experiences, such as education, occupation and leisure activities, is thought to mitigate the effects of the aging process and account for variability in trajectories of cognitive decline. Based on combined behavioral and neuroimaging (voxel-based morphometry) analyses of demographic, cognitive and neural markers of aging and cognitive reserve proxy measures, we examine here predictors of variability in the age-related changes in attention function, indexed by ability to supress salient distraction. Our findings indicate that in healthy (neurotypical) aging gray matter volume within several right lateralised fronto-parietal brain regions varies according to both levels of cognitive reserve (education) and the capacity to effectively select visual stimuli amidst salient distraction. Thus, we provide here novel experimental evidence supporting Robertson’s theory of a right lateralized neural basis for cognitive reserve.

Right fronto-parietal networks mediate the neurocognitive benefits of enriched environments.

“…To the best of our knowledge, this is the first study providing direct evidence linking microstructural properties of a long-range association pathway within the right fronto-parietal networks (the right SLF1) to behavioural markers of neurocognitive reserve and brain health. Here we discuss how these results corroborate our previous work (Brosnan et al, 2017; Brosnan et al, 2018, Shalev et al, 2020) and that of others (Van Loenhoud et al 2017), to provide further experimental evidence in support of the theory that enriched environments strengthen right hemisphere fronto-parietal networks to facilitate the phenomenon of cognitive reserve (Robertson 2013, 2014).…”

“…Although the beneficial effects of EE for neurocognitive resilience are well established, the mechanisms by which this occurs are still under considerable debate. The findings presented here, in concert with our previous findings (Brosnan et al 2017; Shalev et al 2020) suggest that anatomical properties within the right fronto-parietal networks might be neural correlates of resilience in the ageing brain. In further support of this hypothesis, brain stimulation targeting the right fronto-parietal networks not only improves behavioural and EEG markers of attention but also temporarily alters the lateralised impact of a lifetime experiences in low reserve individuals such that it resembles that of their high reserve peers (Brosnan, Arvaneh, et al 2018; Brosnan, Demaria, et al 2018).…”

“…Our previous work using mathematical models of visual attention (Brosnan et al, 2017), causal manipulation techniques (Brosnan et al, 2017; Brosnan et al, 2018) and voxel based morphometry (Shalev et al, 2020) provide increasing support for the proposal that EE may facilitate neuroprotective resilience through specifically impacting the structural (grey matter volume) and function (lateralised asymmetry of visual processing speed) of right hemisphere fronto-parietal regions (see also Van Loenhoud et al 2017; and see Robertson 2013, 2014 for a detailed review theorising right lateralised underpinnings of reserve). Cortical regions within the fronto-parietal networks are connected by white matter association pathways comprising three branches of the superior longitudinal fasciculus (SLF1, SLF2 and SLF3; Thiebaut de Schotten et al, 2011).…”

Strategies and cognitive reserve to preserve lexical production in aging

“…Altered composition of the gut microbiome may be a mechanism linking inadequate sleep to low cognitive abilities in older adults. In addition, a cognitively enriched environment that may be achieved through education may be associated with right-lateralized fronto-parietal networks, which in turn contributes to the preservation of cognitive function in aging by offsetting the age-related decline in the ability to ignore salient distraction, as mentioned by Shalev et al [169]. Indeed, as the authors explain, the ability to suppress distractors with age is driven by the right lateralization of neural substrates (including the fronto-parietal attention network, with a key role in cognitive reserve.…”

Right fronto-parietal networks mediate the neurocognitive benefits of enriched environments

“…Our previous work using mathematical models of visual attention, 34 causal manipulation techniques 34 , 35 and voxel-based morphometry 36 provide increasing support for the proposal that EE may facilitate neuroprotective resilience through specifically impacting the structural [grey matter (GM) volume] and function (lateralized asymmetry of visual processing speed) of right hemisphere fronto-parietal regions (see Van Loenhoud et al 37 and Robertson et al 19 , 20 for a detailed review theorizing right lateralized underpinnings of reserve). Cortical regions within the fronto-parietal networks are connected by WM association pathways comprising three branches of the superior longitudinal fasciculus (SLF) (SLF1, SLF2 and SLF3).…”