Age-dependent modulation of motor network connectivity for skill acquisition, consolidation and interlimb transfer after motor practice

Objective: Age-related differences in neural strategies for motor learning are not fully understood. We determined the effects of age on the relationship between motor network connectivity and motor skill acquisition, consolidation, and interlimb transfer using dynamic imaging of coherent sources. Methods: Healthy younger (n = 24, 18-24 y) and older (n = 24, 65-87 y) adults unilaterally practiced a visuomotor task and resting-state electroencephalographic data was acquired before and after practice as well as at retention. Results: The results showed that right-hand skill acquisition and consolidation did not differ between age groups. However, age affected the ability to transfer the newly acquired motor skill to the non-practiced limb. Moreover, strengthened left- and right-primary motor cortex-related beta conectivity was negatively and positively associated with right-hand skill acquisition and left-hand skill consolidation in older adults, respectively. Conclusion: Age-dependent modulations of bilateral resting-state motor network connectivity indicate age-specific strategies for the acquisition, consolidation, and interlimb transfer of novel motor tasks. Significance: The present results provide insights into the mechanisms underlying motor learning that are important for the development of interventions for patients with unilateral injuries. (C) 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved

Neural Correlates of Motor Skill Learning Are Dependent on Both Age and Task Difficulty

Although a general age-related decline in neural plasticity is evident, the effects of age on neural plasticity after motor practice are inconclusive. Inconsistencies in the literature may be related to between-study differences in task difficulty. Therefore, we aimed to determine the effects of age and task difficulty on motor learning and associated brain activity. We used task-related electroencephalography (EEG) power in the alpha (8-12 Hz) and beta (13-30 Hz) frequency bands to assess neural plasticity before, immediately after, and 24-h after practice of a mirror star tracing task at one of three difficulty levels in healthy younger (19-24 yr) and older (65-86 yr) adults. Results showed an age-related deterioration in motor performance that was more pronounced with increasing task difficulty and was accompanied by a more bilateral activity pattern for older vs. younger adults. Task difficulty affected motor skill retention and neural plasticity specifically in older adults. Older adults that practiced at the low or medium, but not the high, difficulty levels were able to maintain improvements in accuracy at retention and showed modulation of alpha TR-Power after practice. Together, these data indicate that both age and task difficulty affect motor learning, as well as the associated neural plasticity

Failure to Engage Neural Plasticity through Practice of a High-difficulty Task is Accompanied by Reduced Motor Skill Retention in Older Adults

White the difficulty of a motor task can act as a stimulus for learning in younger adults, it is unknown how task difficulty interacts with age-related reductions in motor performance and altered brain activation. We examined the effects of task difficulty on motor performance and used electroencephalography (EEG) to probe task-related brain activation after acquisition and 24-h retention of a mirror star-tracing skill in healthy older adults (N = 36, 65-86 years). The results showed that the difficulty of the motor skill affected both the magnitude of motor skill learning and the underlying neural mechanisms. Behavioral data revealed that practicing a motor task at a high difficulty level hindered motor skill consolidation. The EEG data indicated that task difficulty modulated changes in brain activation after practice. Specifically, a decrease in task-related alpha power in frontal and parietal electrodes was only present after practice of the skill at the low and medium, but not the high difficulty level. Taken together, our findings show that a failure to engage neural plasticity through practice of a highdifficulty task is accompanied by reduced motor skill retention in older adults. The data help us better understand how older adults learn new motor skills and might have implications for prescribing motor skill practice according to its difficulty in rehabilitation settings. (c) 2020 The Author(s). Published by Elsevier Ltd on behalf of IBRO. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Triplet Exciton Generation in Bulk-Heterojunction Solar Cells based on Endohedral Fullerenes

Organic bulk-heterojunctions (BHJ) and solar cells containing the trimetallic nitride endohedral fullerene 1-[3-(2-ethyl)hexoxy carbonyl]propyl-1-phenyl-Lu3N@C80 (Lu3N@C80-PCBEH) show an open circuit voltage (VOC) 0.3 V higher than similar devices with [6,6]-phenyl-C[61]-butyric acid methyl ester (PC61BM). To fully exploit the potential of this acceptor molecule with respect to the power conversion efficiency (PCE) of solar cells, the short circuit current (JSC) should be improved to become competitive with the state of the art solar cells. Here, we address factors influencing the JSC in blends containing the high voltage absorber Lu3N@C80-PCBEH in view of both photogeneration but also transport and extraction of charge carriers. We apply optical, charge carrier extraction, morphology, and spin-sensitive techniques. In blends containing Lu3N@C80-PCBEH, we found 2 times weaker photoluminescence quenching, remainders of interchain excitons, and, most remarkably, triplet excitons formed on the polymer chain, which were absent in the reference P3HT:PC61BM blends. We show that electron back transfer to the triplet state along with the lower exciton dissociation yield due to intramolecular charge transfer in Lu3N@C80-PCBEH are responsible for the reduced photocurrent

"GET-UP" study rationale and protocol: A cluster randomised controlled trial to evaluate the effects of reduced sitting on toddlers' cognitive development

Background: The educational and cognitive differences associated with low socioeconomic status begin early in life and tend to persist throughout life. Coupled with the finding that levels of sedentary time are negatively associated with cognitive development, and time spent active tends to be lower in disadvantaged circumstances, this highlights the need for interventions that reduce the amount of time children spend sitting and sedentary during childcare. The proposed study aims to assess the effects of reducing sitting time during Early Childhood Education and Care (ECEC) services on cognitive development in toddlers from low socio-economic families. Methods/Design: We will implement a 12-months 2-arm parallel group cluster randomised controlled trial (RCT) with Australian toddlers, aged 12 to 26 months at baseline. Educators from the ECEC services allocated to the intervention group will receive professional development on how to reduce sitting time while children attend ECEC. Participants' cognitive development will be assessed as a primary outcome, at baseline and post-intervention, using the cognitive sub-test from the Bayley Scales of Infant and Toddler Development. Discussion: This trial has the potential to inform programs and policies designed to optimize developmental and health outcomes in toddlers, specifically in those from disadvantaged backgrounds