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Objective: Habits, defined as well‐learned associations between cues and behaviours, are essential for health‐related behaviours, including physical activity (PA). Despite the sensitivity of habits to context changes, little remains known about the influence of a context change on the interplay between PA habits and behaviours. We investigated the evolution of PA habits amidst the spring COVID‐19 lockdown, a major context change. Moreover, we examined the association of PA behaviours and autonomous motivation with this evolution. Design: Three‐wave observational longitudinal design. Methods: PA habits, behaviours, and autonomous motivation were collected through online surveys in 283 French and Swiss participants. Variables were self‐reported with reference to three time‐points: before‐, mid‐, and end‐lockdown. Results: Mixed effect modelling revealed a decrease in PA habits from before‐ to mid‐lockdown, especially among individuals with strong before‐lockdown habits. Path analysis showed that before‐lockdown PA habits were not associated with mid‐lockdown PA behaviours (β = −.02, p =.837), while mid‐lockdown PA habits were positively related to end‐lockdown PA behaviours (β =.23, p =.021). Autonomous motivation was directly associated with PA habits (ps <.001) and withto before‐ and mid‐lockdown PA behaviours (ps <.001) (but not with end‐lockdown PA behaviours) and did not moderate the relations between PA behaviours and habits (ps >.072). Conclusion: PA habits were altered, and their influence on PA behaviours was impeded during the COVID‐19 lockdown. Engagement in PA behaviours and autonomous motivation helped in counteracting PA habits disruption. [ABSTRACT FROM AUTHOR]

Background: Weak muscle strength has been associated with a wide range of adverse health outcomes. Yet, whether individuals with weaker muscle strength are more at risk for hospitalization due to severe COVID‐19 is still unclear. The objective of this study was to investigate the independent association between muscle strength and COVID‐19 hospitalization. Methods: Data from adults 50 years of age or older were analysed using logistic models adjusted for several chronic conditions, body‐mass index, age, and sex. Hand‐grip strength was repeatedly measured between 2004 and 2017 using a handheld dynamometer. COVID‐19 hospitalization during the lockdown was self‐reported in summer 2020 and was used as an indicator of COVID‐19 severity. Results: The study was based on the Survey of Health, Ageing and Retirement in Europe (SHARE) and included 3600 older adults (68.8 ± 8.8 years, 2044 female), among whom 316 were tested positive for the severe acute respiratory syndrome coronavirus 2 (8.8%), and 83 (2.3%) were hospitalized due to COVID‐19. Results showed that higher grip strength was associated with a lower risk of COVID‐19 hospitalization [adjusted odds ratio (OR) per increase of 1 standard deviation in grip strength = 0.64, 95% confidence interval (95% CI) = 0.45–0.87, P = 0.015]. Results also showed that age (OR for a 10 ‐year period = 1.70, 95% CI = 1.32–2.20, P < 0.001) and obesity (OR = 2.01, 95% CI = 1.00–3.69, P = 0.025) were associated with higher risk of COVID‐19 hospitalization. Sensitivity analyses using different measurements of grip strength as well as robustness analyses based on rare‐events logistic regression and a different sample of participants (i.e. COVID‐19 patients) were consistent with the main results. Conclusions: Muscle strength is an independent risk factor for COVID‐19 severity in adults 50 years of age or older. [ABSTRACT FROM AUTHOR]

Attentional capture by exercise‐related stimuli is important for the regulation of physical activity. Attentional processing underlying this capture has been investigated with indirect behavioral measures based on reaction times. To investigate more direct measures of visual spatial attention toward physical activity (vs. inactivity) stimuli, we used eye‐tracking and a visual dot probe task in 77 young adults with various level of physical activity. Reaction times to detect a dot appearing in the area previously occupied by a physical activity (vs. inactivity) stimulus were an indirect measure of attentional bias. The first picture gaze and viewing time were more direct measures of attentional orienting and attentional engagement, respectively. Pupil dilation was an indicator of arousal. Reaction times revealed a two‐way interaction between the location of the dot and participants' usual level of physical activity. Only participants with a high level of physical activity more quickly detected a dot when it appeared in the area previously occupied by a physical activity stimulus. Eye‐tracking results showed greater odds of first gazing at physical activity stimuli and for a longer time, and a greater decrease in pupil size when viewing physical activity stimuli when usual level of physical activity was moderate or high, but not low. The variance explained in the outcomes ranged from 13.9% (pupil dilation) to 40% (reaction times). Overall, as hypothesized, compared to less physically active participants, participants who were more physically active demonstrated indirect (reaction times) and direct (first gaze, viewing time) evidence of a more pronounced attentional bias toward physical activity. Physical activity stimuli biased attention, with a pronounced effect when the level of physical activity was higher. These findings suggest that physical activity stimuli are relevant to the current concerns of moderately and highly active individuals. Behavioral studies based on reaction‐time tasks suggest that active individuals are attentionally biased toward physical activity. Here, based on eye‐tracking evidence, we show that moderately‐to‐highly active individuals orient their attention toward physical activity stimuli more often and for longer periods of time than toward physical inactivity stimuli. Interventions aiming to promote physical activity might benefit from testing the effectiveness of attentional bias modification treatments. [ABSTRACT FROM AUTHOR]

Physiological aging affects brain structure and function impacting morphology, connectivity, and performance. However, whether some brain connectivity metrics might reflect the age of an individual is still unclear. Here, we collected brain images from healthy participants (N = 155) ranging from 10 to 80 years to build functional (resting state) and structural (tractography) connectivity matrices, both data sets combined to obtain different connectivity features. We then calculated the brain connectome age—an age estimator resulting from a multi‐scale methodology applied to the structure–function connectome, and compared it to the chronological age (ChA). Our results were twofold. First, we found that aging widely affects the connectivity of multiple structures, such as anterior cingulate and medial prefrontal cortices, basal ganglia, thalamus, insula, cingulum, hippocampus, parahippocampus, occipital cortex, fusiform, precuneus, and temporal pole. Second, we found that the connectivity between basal ganglia and thalamus to frontal areas, also known as the fronto‐striato‐thalamic (FST) circuit, makes the major contribution to age estimation. In conclusion, our results highlight the key role played by the FST circuit in the process of healthy aging. Notably, the same methodology can be generally applied to identify the structural–functional connectivity patterns correlating to other biomarkers than ChA. [ABSTRACT FROM AUTHOR]

Abstract: The ability to learn new motor skills is crucial for activities of daily living, especially in older adults. Previous work in younger adults has indicated fast and slow stages for motor learning that were associated with changes in functional interactions within and between brain hemispheres. However, the impact of the structural scaffolds of these functional interactions on different stages of motor learning remains elusive. Using diffusion‐weighted imaging and probabilistic constrained spherical deconvolution‐based tractography, we reconstructed transcallosal white matter pathways between the left and right primary motor cortices (M1–M1), left dorsal premotor cortex and right primary motor cortex (LPMd–RM1) and right dorsal premotor cortex and left primary motor cortex (RPMd–LM1) in younger and older adults trained in a set of bimanual coordination tasks. We used fractional anisotropy (FA) to assess microstructural organisation of the reconstructed white matter pathways. Older adults showed lower behavioural performance than younger adults and improved their performance more in the fast but less in the slow stage of learning. Linear mixed models predicted that individuals with higher FA of M1–M1 pathways improve more in the fast but less in the slow stage of bimanual learning. Individuals with higher FA of RPMd–LM1 improve more in the slow but less in the fast stage of bimanual learning. These predictions did not differ significantly between younger and older adults suggesting that, in both younger and older adults, the M1–M1 and RPMd–LM1 pathways are important for the fast and slow stage of bimanual learning, respectively. [ABSTRACT FROM AUTHOR]

For successful motor control, the central nervous system is required to combine information from the environment and the current body state, which is provided by vision and proprioception respectively. We investigated the relative contribution of visual and proprioceptive information to upper limb motor control and the extent to which structural brain measures predict this performance in youth ( n = 40; age range 9-18 years). Participants performed a manual tracking task, adopting in-phase and anti-phase coordination modes. Results showed that, in contrast to older participants, younger participants performed the task with lower accuracy in general and poorer performance in anti-phase than in-phase modes. However, a proprioceptive advantage was found at all ages, that is, tracking accuracy was higher when proprioceptive information was available during both in- and anti-phase modes at all ages. The microstructural organization of interhemispheric connections between homologous dorsolateral prefrontal cortices, and the cortical thickness of the primary motor cortex were associated with sensory-specific accuracy of tracking performance. Overall, the findings suggest that manual tracking performance in youth does not only rely on brain regions involved in sensorimotor processing, but also on prefrontal regions involved in attention and working memory. Hum Brain Mapp 38:5628-5647, 2017. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

There is a convergence in the literature toward a critical role for the basal ganglia in action selection. However, which substructures within the basal ganglia fulfill this role is still unclear. Here we used shape analyses of structural magnetic resonance imaging data to determine the extent to which basal ganglia structures predict performance in easy and complex multilimb reaction-time tasks in young and old adults. Results revealed that inward deformation (i.e., local atrophy) of the nucleus accumbens and caudate were predictive of longer action selection times in complex conditions, but not in easy conditions. Additionally, when assessing the relation between behavioral performance and the shape of the left nucleus accumbens in the two age groups separately, we found a significant performance-structure association in old, but not young adults. This result suggests that the relevance of the nucleus accumbens for the process of action selection increases with age. Hum Brain Mapp 37:4629-4639, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]