Neuroscience
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Patients experiencing severe hemiplegia following a stroke struggle to rehabilitate their affected limbs. Cross-education (CE) training emerges as a promising rehabilitation method due to its safety, simplicity, low risk, and ability to effectively improve muscle strength in the affected limb. However, controversy surrounds the neural mechanisms and clinical applications of CE. ⋯ SIGNIFICANCE STATEMENT: Exploring the neural mechanisms underlying one session of 50% MVC strength training with less-affected hand sheds light on a safe therapy. The study enhances our understanding of less-affected hand training and investigates the feasibility as a future rehabilitation approach. Analyzing how one session of 50% MVC strength training with less-affected hand affects brain activation and connectivity could lead to more tailored and effective rehabilitation strategies.
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Controversy persists regarding the representation of linguistically negated actions, specifically concerning activation and inhibitory mechanisms in the motor system, and whether negated action sentences evoke an initial motor simulation of the action to be negated. We conducted two experiments probing corticospinal excitability (CSE) and short-interval intracortical inhibition (SICI) in the primary motor cortex at different latencies while reading affirmative and negative action sentences. In experiment one, twenty-six participants read action and non-action sentences in affirmative or negative forms. ⋯ Negated action sentences showed the same motor excitability as affirmed action sentences with no additional inhibition at early latencies. These results lend support for the idea that actions to be negated are initially simulated within the motor system. Neural differences between affirmative and negative action sentences may occur outside the primary motor cortex.
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Reductions in circulating estrogens can contribute to cognitive decline, in part by impairing mitochondrial function within the hippocampal region. The entorhinal cortex provides the hippocampus with its main cortical inputs. To assess the impact of estrogen deficiency on mitochondrial respiration and synaptic proteins in the entorhinal cortex, female wildtype rats received either sham surgery, bilateral ovariectomy, or ovariectomy with implantation of a subdermal capsule to maintain low levels of circulating 17β-estradiol (E2). ⋯ Further, the ovariectomy-induced changes in mitochondrial proteins were associated with reductions in postsynaptic density protein 95 (PSD95) and the presynaptic protein synaptophysin. There were no changes in mitochondrial or synaptic proteins in ovariectomized animals that received E2 supplementation. Our findings indicate that reductions in circulating 17β-estradiol induced by ovariectomy disrupt mitochondrial functions in the entorhinal cortex, and suggest that a resulting increase in oxidative stress contributes to the degradation in synaptic proteins that may affect cognitive functions mediated by the hippocampal region.
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In the last years, there has been a growing interest in the brain-heart connection. A core aspect of this connection appears to be the autonomic nervous system, particularly through the vagus nerve. Accordingly, vagally mediated heart rate variability (vmHRV) is currently considered as an index of top-down control processes involved in cognition and emotion regulation. ⋯ Participants with higher resting vagal tone showed superior cognitive performance in tasks requiring cognitive control, motor and cognitive inhibition, cognitive flexibility, and working memory in comparison to those with lower resting vagal tone. Furthermore, vagal-mediated heart rate variability was also found to be associated with memory, attention, and executive performance. The current research provides new insights into the interactions between cognitive and autonomic systems, further supporting evidence for body-brain interactions.
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Alzheimer's disease (AD) is a common neurodegenerative disease, neuroinflammation is an early pathological feature of AD. However, the alteration of the immune microenvironment in asymptomatic AD was not fully explained. In this study, we aimed to utilize the transcriptome data of AD patients in public databases to reveal the change of immune microenvironment in asymptomatic AD and screen the potential drug targets. ⋯ Moreover, HLA-C is expressed in the microglia cells and astrocytes. Further, five FDA-approved drugs (Itrazole, Dfo, Syrosingopine, Cefoperazone, and Pradaxa) were predicted as the common drug targeting HLA-C and HLA-DRB1 by molecular docking. Taken together, the results revealed the changes in the immune microenvironment of asymptomatic AD and provided a new perspective for the development of anti-inflammatory drugs for AD early treatment.