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Background: Accumulating evidence suggests that higher Mediterranean diet (MedDiet) adherence is associated with higher global cognitive performance and brain structural integrity as well as decreased risk of Alzheimer disease (AD) and vascular dementia (VaD). Objectives: We directly examined cross-sectional associations between the MedDiet and cognitive and neuroimaging phenotypes associated with AD and VaD (separately) in a cohort of nondemented, nondepressed older adults. Methods: Community-dwelling older adults (n = 82; aged ∼68.8 y; 50% female, 50% minority) underwent dietary (Block Food Frequency Questionnaire 2005) and neuropsychological assessments and neuroimaging. MedDiet scores were quantified with the use of published criteria, and participants were divided into High and Low (median split) adherence groups. We focused our neuropsychological investigation on cognitive phenotypes primarily associated with AD [i.e., learning and memory (L&M)] and VaD (i.e., information processing and executive functioning). AD neuroimaging phenotypes consisted of hippocampal and dentate gyrus volumes quantified using T1-weighted images and the FreeSurfer 6.0 segmentation pipeline (http://surfer.nmr.mgh.harvard.edu). The VaD neuroimaging phenotype consisted of total white matter hyperintensity (WMH) volumes quantified using combined T1-weighted and T2-fluid-attenuated inversion recovery images. Neuroimaging metrics were adjusted for total intracranial volume. Separate multivariable linear regression models controlling for age, sex, education, body mass index, and caloric intake examined the associations between MedDiet groups (High compared with Low) and cognitive and neuroimaging outcomes. Results: When compared with the Low MedDiet group, the High MedDiet group was associated with better L&M performance and larger dentate gyri. MedDiet adherence was not associated with information processing, executive functioning, or WMH. Conclusion: Results highlight the association between increasing MedDiet adherence and specific cognitive and neuroimaging phenotypes that, when altered, are associated with AD. [ABSTRACT FROM AUTHOR]

Greater brain network integrity may associate with physically active lifestyles. Three resting state networks may provide unique insights into known physical activity-mediated brain health benefits: the default mode network (involved with self-monitoring), the salience network (involved in orienting oneself to salient external and internal stimuli), and the central executive network (responsible for higher level cognitive task). The current study explored relationships between system-wide neural network integrity measured by functional magnetic resonance imaging and objectively-measured physical activity. We hypothesize connectivity patterns as measured by fMRI networks will relate to actigraphy markers such that 1) there will be higher connectivity within the central executive network in more physically active individuals, and 2) there will be higher connectivity within the default mode network and salience network in those with higher levels of physical activity. Eighteen non-demented older adults with orthopedic pain (age 67.11 ± 5.61, 50% female, education 15.94 ± 2.51 years) completed brain magnetic resonance imaging, and wore an actigraphy device to objectively measure types of physical and sedentary engagement. Results showed a negative relationship between central executive network connectivity and sedentary time (β = ‐0.108, p =.039), and a positive relationship with both moderate-to-vigorous physical activity (β = 0.629, p =.029) and total activity time (β = 0.645, p =.039). Results also showed positive relationships for the default mode network (β = 0.588, p =.033) and the salience network (β = 0.608, p =.037) with mean cadence (i.e. steps per minute). Our work adds to the existing literature on specific types of activity measurement (i.e. sedentary time, cadence and moderate-to-vigorous physical activity) which will be useful for interventions aimed at improving the integrity of underlying neural networks. [ABSTRACT FROM AUTHOR]

The oblique effect (OE) describes the visuospatial advantage for identifying stimuli oriented horizontally or vertically rather than diagonally; little is known about brain aging and the OE. We investigated this relationship using the Judgment of Line Orientation (JLO) in 107 older adults (∼age = 67.8 ± 6.6; 51% female) together with neuropsychological tests of executive functioning (EF), attention/information processing (AIP), and neuroimaging. Only JLO lines falling between 36-54° or 126–144° were considered oblique. To quantify the oblique effect, we calculated z-scores for oblique errors (zOblique = #oblique errors/#oblique lines), and similarly, horizontal + vertical line errors (zHV), and a composite measure of oblique relative to HV errors (zOE). Composite z-scores of EF and AIP reflected domains associated with JLO performance. Graph theory analysis integrated T1-derived volumetry and diffusion MRI-derived white matter tractography into connectivity matrices analyzed for select network properties. Participants produced more zOblique than zHV errors (p < 0.001). Age was not associated with zOE adjusting for sex, education, and MMSE. Similarly adjusted linear regression models revealed that lower EF was associated with a larger oblique effect (p < 0.001). Modular analyses of neural connectivity revealed a differential patterns of network affiliation that varied by high versus low group status determined via median split of zOblique and zHV errors, separately. Older adults exhibit the oblique effect and it is associated with specific cognitive processes and regional brain networks that may facilitate future investigations of visuospatial preference in aging. • Oblique effect = advantage for stimuli angled horizontal/vertical rather than diagonal. • Older non-demented adults produced more oblique than horizontal/vertical (HV) errors. • Lower executive functioning was associated with a larger oblique effect. • Differential patterns of neural connectivity associated with oblique and HV errors. [ABSTRACT FROM AUTHOR]