The functional connectome of cognitive reserve

Abstract

Cognitive Reserve (CR) designates the brain's capacity to actively cope with insults through a more efficient use of its resources/networks. It was proposed in order to explain the discrepancies between the observed cognitive ability and the expected capacity for an individual. Typical proxies of CR include education and Intelligence Quotient but none totally account for the variability of CR and no study has shown if the brain's greater efficiency associated with CR can be measured. We used a validated model to estimate CR from the residual variance in memory and general executive functioning, accounting for both brain anatomical (i.e., gray matter and white matter signal abnormalities volume) and demographic variables (i.e., years of formal education and sex). Functional connectivity (FC) networks and topological properties were explored for associations with CR. Demographic characteristics, mainly accounted by years of formal education, were associated with higher FC, clustering, local efficiency and strength in parietal and occipital regions and greater network transitivity. Higher CR was associated with a greater FC, local efficiency and clustering of occipital regions, strength and centrality of the inferior temporal gyrus and higher global efficiency. Altogether, these findings suggest that education may facilitate the brain's ability to form segregated functional groups, reinforcing the view that higher education level triggers more specialized use of neural processing. Additionally, this study demonstrated for the first time that CR is associated with more efficient processing of information in the human brain and reinforces the existence of a fine balance between segregation and integration. Hum Brain Mapp 37:3310–3322, 2016.. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Lifestyle activities in mid-life contribute to cognitive reserve in late-life, independent of education, occupation and late-life activities

“…Another key objective for future research is identification of the neural mechanisms by which MA supports late life cognitive ability. One possibility is that MA alters the functional networks subserving cognitive processes, rendering them more resilient to structural brain atrophy (Marques et al 2016, Stern 2017. Identification of the underlying mechanisms will have relevance not just for the understanding of cognitive reserve but also for the emerging concept of brain maintenance (Nyberg et al 2012).…”

Comparative Effects of Education and Bilingualism on the Onset of Mild Cognitive Impairment

“…It has been suggested that the interactional contexts bilinguals find themselves in (single language, dual language, and code-switching) lead them to adapt various cognitive control processes that result in efficient use of control networks [15]. Structural brain changes and reorganization of brain networks, which in turn sustain cognitive performance during aging, have also been demonstrated with both education and bilingualism [16,17,18,19]. …”

The independent influences of age and education on functional brain networks and cognition in healthy older adults

“…The proxies of CR are associated with a relative preservation of brain structure and more efficient neural activity during cognitive demands [Bartr es-Faz and Arenaza-Urquijo, 2011]. Increased educational attainment is also associated with increased resting-state functional connectivity in distributed cortical networks [Marques et al, 2015[Marques et al, , 2016. However, the influence of moderating factors such as education on the cognitive networks sensitive to age-related changes are poorly understood [Bartr es-Faz and Arenaza-Urquijo, 2011;Stern, 2009;Stern et al, 2008].…”