Neuroscience
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Growing awareness of adverse impacts of artificial light on human health has led to recognize light pollution as a significant global environmental issue. Despite, a large number of studies in rodent and monkey models of Parkinson's disease have reported that near infrared light has neuroprotective effects on dopaminergic neurons, recent findings have shown that prolonged exposure of rodents and birds to fluorescent artificial light results in an increase of neuromelanin granules in substantia nigra and loss of dopaminergic neurons. ⋯ The present article discusses experimental evidence supporting a potentially deleterious impact of light on dopaminergic neurons and highlights the mechanisms whereby light might damage neuronal tissue. Moreover, it analyses epidemiological evidence that suggests light pollution to be an environmental risk factor for Parkinson's disease.
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Neurophysiological correlates of adaptation and interference during asymmetrical bimanual movements.
In this study, we investigated brain dynamics during interference between hands during bimanual movements. Participants performed a bimanual center-out reaching task in which a visuomotor rotation was applied to the right hand while the left hand did not receive visual feedback of its movements. This manipulation resulted in interference from the adapting right hand to the kinesthetically guided left hand. ⋯ This may be representative of error-based updating of internal models of movement. Additionally, coherence, a measure of neural functional connectivity, was elevated both within and between hemispheres in the beta frequencies during the initial presentation of the visuomotor rotation, and then decreased throughout adaptation. This suggests that beta oscillatory neural activity may be marker for transmission of conflicting motor information between hemispheres, which manifests in interference between the hands during asymmetrical bimanual movements.
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Rotational uncertainty refers to the fact that the reaction time (RT) for identifying an upright stimulus is longer when the target stimulus is presented in a sequence of stimuli with different orientations (SU condition) than upright stimuli only (AU condition). Up until now, the rotational uncertainty effect has been only revealed by behavior measures, and its underlying neural mechanism remains unclear. In this study, using the hand mental rotation paradigm and electroencephalogram (EEG) recordings, we aimed to find the electrophysiological evidences of the rotational uncertainty from event-related potential (ERP) and event-related (de)synchronization (ERS/ERD) measurements. ⋯ Our results suggested that identifying the upright hand stimuli in SU condition induced more activation of motor networks, and the rotational uncertainty influenced multiple cognitive processes from the early visual processing to the late mental rotation and judging phases. The results implied that in SU condition, subjects might maintain readiness for the next possible mental rotation immediately after the previous response, with more attention to the coming visual stimuli. Even for the upright stimuli, they might still prepare for the mental rotation, and even mentally rotate the stimuli in a minor angle.
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Protein and miRNA enrichment within extracellular vesicles (EVs) isolated from patients with Alzheimer's disease (AD) has been shown to have putative diagnostic value. However, whether a combination of both will be more advantageous is unknown. EVs were enriched from serum samples obtained from patients with sporadic AD (n = 13), mild cognitive impairment (MCI) (n = 10), vascular dementia (VaD) (n = 10), and healthy controls (HC) (n = 10). ⋯ Hsa-miR-1306-5p, hsa-miR-342-3p, and hsa-15b-3p were all significantly downregulated in patients with AD compared to HC (P < 0.05), only hsa-miR-1306-5p expression was differentially expressed between AD, MCI, and VaD samples. Similarly, whereas all 14 miRNAs were significantly upregulated in patients with AD compared to HC, only hsa-miR-93-5p, hsa-miR-424-5p, and hsa-miR-3065-5p were differentially expressed when AD samples were compared to MCI and VaD samples. Even though the sample size was small, the results of the current pilot study indicates that hsa-miR-1306-5p, hsa-miR-93-5p, hsa-miR-424-5p, and hsa-miR-3065-5p, and expression of P-S396-tau in EVs might provide a combinatorial protein and miRNA signature to differentiate between HC, patients with MCI or VaD from patient with sporadic AD.
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The possibility that exposure to inhalation anaesthetics inhibits neurogenesis and results in memory deficits has attracted considerable interest over the past decade. This study was designed to investigate the mechanism of the sevoflurane exposure-induced decline in hippocampal neurogenesis. Young mice were anaesthetized with a gaseous mixture of 3.0% sevoflurane/60% oxygen 2 h daily for three consecutive days. ⋯ Concomitantly, BDNF and TrkB expression, which was decreased by sevoflurane, was also restored by NaB. Our study showed that sevoflurane affects long-term neurocognitive function and neurogenesis in young mice. Normalization of histone acetylation may alleviate the neurodevelopmental side effects of this anaesthetic.