Neuroscience
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Motor learning does not occur on a 'blank slate', but in the context of prior coordination solutions. The role of prior coordination solutions is likely critical in redundant tasks where there are multiple solutions to achieve the task goal - yet their influence on subsequent learning is currently not well understood. Here we addressed this issue by having human participants learn a redundant virtual shuffleboard task, where they held a bimanual manipulandum and made a discrete throwing motion to slide a virtual puck towards a target. ⋯ On the second day, all participants transferred to a common criterion task, which required an asymmetric solution. Results showed that: (i) the symmetry of the practiced solution affected motor variability during practice, with more asymmetric solutions showing higher exploration of the null space, (ii) when transferring to the common criterion task, participants in the symmetric group showed much higher null space exploration, and (iii) when no constraints were placed on the solution, participants tended to return to the symmetric solution regardless of the solution originally practiced. Overall, these results suggest that the stability of prior coordination solutions plays an important role in shaping learning in redundant motor tasks.
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Alzheimer's disease (AD) remains a pressing global health concern, necessitating comprehensive investigations into its underlying molecular mechanisms. While the late-stage pathophysiology of this disease is well understood, it is crucial to examine the role of amyloid beta oligomers (Aβo), which form in the brain during the early stages of disease development. These toxic oligomers could affect neuronal viability and generate oxidative stress in the brain. ⋯ Our study also revealed the involvement of less-explored proteins like MYH9, CISD1, and SNRNP70, which play critical roles in cytoskeletal dynamics, mitochondrial function, and RNA splicing, respectively. These findings underscore the complex pathophysiology of AD, highlighting potential biomarkers and therapeutic targets for early intervention. The present study advances the understanding of Aβo-induced oxidative stress and neuronal damage, providing a foundation for future research into early-stage AD diagnosis and subsequent treatment strategies.
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This study investigates the therapeutic effect of astrocyte-derived extracellular vesicles (EVs) in mitigating neurotoxicity-induced transcriptome changes, mitochondrial function, and base excision repair mechanisms in human brain endothelial cells (HBECs). Neurodegenerative disorders are marked by inflammatory processes impacting the blood-brain barrier (BBB) that involve its main components- HBECs and astrocytes. Astrocytes maintain homeostasis through various mechanisms, including EV release. ⋯ High-throughput RNA sequencing revealed that exposure to Na2Cr2O7 suppressed immune response genes. The addition of astrocyte-derived EVs resulted in the dysregulation of long noncoding RNAs impacting genes associated with brain development and angiogenesis. These findings reveal the positive impact of astrocytes-derived EVs in mitigating neurotoxicity and as potential therapeutic avenues for neurodegenerative diseases.
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The glymphatic system theory postulates that brain waste is removed through the cerebrospinal fluid (CSF) flow. According to this theory, CSF in the subarachnoid space (SAS) moves to the perivascular space around the penetrating arteries, flows into parenchyma to mix with interstitial fluid and brain waste, and then moves to the perivenous space to be flushed out of the brain. Despite the controversies about the glymphatic theory, it is clear that SAS plays a key role in waste clearance. ⋯ We segmented SAS in the whole brain of 83 young adults and divided SAS into four cortical lobes. We demonstrated regional variations in FA and MD within SAS and an age-related decline in FA among young adults, indicating that diffusion within SAS becomes more isotropic with aging. These findings raise new questions about the factors influencing diffusion anisotropy within SAS, which are relevant to glymphatic transport.
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The electrical activity of the brain, characterized by its frequency components, reflects a complex interplay between periodic (oscillatory) and aperiodic components. These components are associated with various neurophysiological processes, such as the excitation-inhibition balance (aperiodic activity) or interregional communication (oscillatory activity). However, we do not fully understand whether these components are truly independent or if different neuromodulators affect them in different ways. ⋯ By parameterizing the power spectrum into these two components, our findings reveal a robust modulation of oscillatory activity by the D2 receptor across the brain. Surprisingly, aperiodic activity was not significantly affected and exhibited inconsistent changes across the brain. This suggests a nuanced interplay between neuromodulation and the distinct components of brain oscillations, providing insights into the selective regulation of oscillatory dynamics in awake states.