Neuroscience
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Multiple sclerosis (MS) is a demyelination disease that causes gradual damage to neurons. Despite the necessity of appropriate treatments at each disease stage to prevent the worsening of the damage, it is still difficult to cure MS. In this study, metabolomics and lipidomics studies were performed with time-course plasma samples (early, peak, chronic phase for MS) to elucidate the mechanism during MS progression after induction of experimental autoimmune encephalomyelitis (EAE), which is the animal model for multiple sclerosis (MS). ⋯ In particular, 26 metabolites showed significant differences at specific stages. The metabolite level of the plasma was significantly altered in response to the EAE pathogenesis, and these changes were related to inflammation status at each disease stage. This study can provide crucial information for reducing damage by differentiating treatment strategies according to disease progression.
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Nerve damage leads to the development of disabling neuropathic pain in susceptible individuals, where patients present with pain as well as co-morbid affective behavioural disturbances, such as anhedonia, decreased motivation and depression. In this study we aimed to characterise changes in neuroinflammation in the medial prefrontal cortex (mPFC) and hippocampus (HP) in a rat model of neuropathic pain (NP) and behavioural changes. 53 rats underwent sciatic nerve chronic constriction injury (CCI) and were characterised as either, No effect, Acute effect or Lasting effect on the basis of changes in exploration behaviour in a radial-arm maze. Microglial and astrocyte morphology, as well as IL-1β, IL-6, IL-10, MCP-1, p38 MAPK and BDNF expression was quantified throughout the mPFC and HP using protein multiplex assays and immunofluorescence. ⋯ This includes increased expression of IL-1β, IL-6 and MCP-1, increased phospho-p38 MAPK expression in neurons and microglia, and a shift to a reactive microglial morphology in the caudal PL and IL, ventral CA1 and DG. Therefore, neuroinflammation in the mPFC and ventral HP may influence individual differences in radial-arm maze behaviour following CCI. Our data provide further evidence that individual differences in neuroimmune activation in the interconnected ventral HP-mPFC circuitry may play a role in the divergent behavioural trajectories following nerve injury, with neuroinflammation being coincident with affective behavioural changes in susceptible individuals.
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Hypoxia inducible factor-1α (HIF-1α) is a key transcription factor that maintains oxygen homeostasis. Hypoxic stress is related to the pathogenesis of amyotrophic lateral sclerosis (ALS), and impaired HIF-1α induces motor neuron degeneration in ALS. Dimethyloxalylglycine (DMOG) upregulates the stability of HIF-1α expression and shows neuroprotective effects, but has not been used in ALS as an anti-hypoxic stress treatment. ⋯ DMOG treatment significantly ameliorated the decrease in HIF-1α expression, the degeneration of both spinal motor neurons and myofibers in lower limbs, gliosis and apoptosis in the spinal cord. This was accompanied by prolonged survival. The present study suggests that in vivo bioluminescence resonance energy transfer (BRET) HIF-1α imaging is useful for evaluating hypoxic stress in ALS, and that the enhancement of HIF-1α is a therapeutic target for ALS patients.
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Exposure to commonly used anesthetics is associated with widespread neuroapoptosis in neonatal animals. Vulnerability of developing hippocampal dentate gyrus granule cells to anesthetic neurotoxicity peaks approximately 2 weeks after cell birth, as measured by bromodeoxyuridine birth dating, regardless of the age of the animal. The present study examined whether the vulnerable window can be further characterized by utilizing a transgenic approach. ⋯ Apoptotic EGFP- granule cells more frequently expressed the immature neuronal marker calretinin (75.4% vs 45.0%, P < 0.001) and less frequently the late progenitor marker NeuroD1 (21.9% vs 87.9%, P < 0.001) than EGFP+ granule cells. Although EGFP- granule cells were more mature in immunostaining than EGFP+ granule cells, their electrophysiological properties partially overlapped in terms of input resistance, resting membrane potential and action potential amplitude. Our results revealed the POMC stage, when GABA acts as an excitatory neurotransmitter, only partly captures susceptibility to anesthetic neurotoxicity, suggesting the vulnerable window of anesthesia-induced neuroapoptosis extends from the end of POMC+ stage to the post-POMC+ stage when depolarizing glutamatergic inputs emerge.
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Understanding brain processing mechanisms from the perception of speech sounds to high-level semantic processing is vital for effective human-robot communication. In this study, 128-channel electroencephalograph (EEG) signals were recorded when subjects were listening to real and pseudowords in Mandarin. By using an EEG source reconstruction method and a sliding-window Granger causality analysis, we analyzed the dynamic brain connectivity patterns. ⋯ This may be related to semantic processing and integration. The involvement of both bottom-up input and top-down modulation in real word processing may support the previously proposed TRACE model. In sum, the findings of this study suggest that representations of speech involve dynamic interactions among distributed brain regions that communicate through time-specific functional networks.