Neuroscience
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The mirror neuron system (MNS) is currently one of the most prominent areas of research in neuroscience. Some of the work has focused on the identification of factors that modulate its activity, but until now, no one has tried to identify the effect of motor ability on the MNS regions. The aim of the present work is to study a possible modulation of hand dexterity on the MNS activity. ⋯ The degree of dexterity only seems to modulate MNS regions during action execution. However, under the observation condition, no linear relationship of hand dexterity in MNS regions was registered in either the comparison between groups, or in the regression analysis. Therefore, the MNS network does not seem to be linearly modulated by the degree of motor dexterity, as occurs with other action-related factors like familiarity.
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Previous research has shown that Parkinson's disease (PD) patients can increase the speed of their movement when catching a moving ball compared to when reaching for a static ball (Majsak et al., 1998). A recent model proposed by Redgrave et al. (2010) explains this phenomenon with regard to the dichotomic organization of motor loops in the basal ganglia circuitry and the role of sensory micro-circuitries in the control of goal-directed actions. According to this model, external visual information that is relevant to the required movement can induce a switch from a habitual control of movement toward an externally-paced, goal-directed form of guidance, resulting in augmented motor performance (Bieńkiewicz et al., 2013). ⋯ We observed how PD patients can adjust their movement kinematics in accordance with the speed of a moving target, even if vision of the target is occluded and patients have to rely solely on auditory information. We demonstrate that the availability of dynamic temporal information is crucial for eliciting motor improvements in PD. Furthermore, these effects appear independent from the sensory modality through-which the information is conveyed.
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Motor learning results from practice but also between practice sessions. After skill acquisition early consolidation results in less interference with other motor tasks and even improved performance of the newly learned skill. A specific significance of the primary motor cortex (M1) for early consolidation has been suggested. ⋯ The data reveal a stepwise decline of alpha-band ERD associated with faster reaction times replicating previous findings. The amount of beta-band suppression was significantly correlated with reduction of reaction times. While changes of alpha power have been related to lower cognitive control after initial skill acquisition, the present data suggest that the amount of beta suppression represents a neurophysiological marker of early cortical reorganization associated with motor learning.
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Decreased levels of soluble ubiquitin carboxy-terminal hydrolase L1 (UCHL1) have been reported in the brains of sporadic Alzheimer's disease (AD) patients, and the introduction of UCHL1 rescued the synaptic and cognitive function of AD model mice. Obviously, a reduction in the levels of UCHL1 may play a role in the pathogenesis of AD. However, the mechanisms underlying the regulation of UCHL1 levels in AD have not been fully elucidated. ⋯ Furthermore, overexpression of microRNA-922 increased the phosphorylated tau levels. In conclusion, miR-922 increasing the levels of phosphorylated tau by regulating UCHL1 levels contributed to the pathogenesis of AD. Our study partly explained one of the mechanisms underlying the downregulation of UCHL1 levels in AD patients and could enrich the content of tau pathology in the pathogenesis of AD.
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Accumulating evidence supports that nicotinamide adenine dinucleotide phosphate (NADPH) oxidase contributes to microglia-mediated neurotoxicity in the CNS neurodegenerative diseases. Several studies, including ours, suggest that microglial activation is involved in the retinal degeneration in the animal models of retinitis pigmentosa (RP). In the present study, we investigated the activation of NADPH oxidase in the rod degeneration in rd mice and further explored its role in the microglia-mediated photoreceptor apoptosis. ⋯ Apocynin markedly reduced the production of superoxide radicals and preserved the rod cells. The results suggested that NADPH oxidase might play an important role in the rod degeneration in the rd mice. Inhibition of NAPDH oxidase could be a possible approach to treat RP in the early degenerative stage.