Neuroscience
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We tested predictions of a hierarchical scheme on the control of natural movements with referent body configurations. Subjects occupied an initial hand position against a bias force generated by a HapticMaster robot. A smooth force perturbation was applied to the hand consisting of an increase in the bias force, keeping it at a new level for 5s, and decreasing it back to the bias value. ⋯ We interpret unintentional movements as consequences of back-coupling between the actual and referent configurations at the task level. The results suggested that both intentional and unintentional movements resulted from shifts of the body referent configuration produced intentionally or as a result of the hypothesized back-coupling. Inter-trial variance signature reflects similar task-specific stability properties of the system following both types of movements, intentional and unintentional.
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Although the neural correlates that underlie abdominal pain have been investigated, so-called brain processes involved in modulating "gut feelings" remain unclear. In the current study, we used electrointestinography (EIG) to measure intestinal activity of healthy humans at rest. EIG measured myoelectrical activity of intestinal smooth muscles from the abdominal surface and was simultaneously conducted along with brain activity measurement using functional magnetic resonance imaging (fMRI). ⋯ Neural activity correlating with 0.14- to 0.21-Hz EIG (suggested to reflect intestinal activity) was observed in the right anterior and middle insula. Moreover, this EIG frequency band correlated with anxiety scores along with resting-state functional connectivity between the insula and dorsal anterior cingulate cortex. These findings suggest that the insular cortex could be the core region involved in central visceral processes associated with subjective feelings.
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To investigate the effect of senescence on signal transmission, we have compared the visual response latency and spontaneous activity of cells in the lateral geniculate nucleus (LGN), area 17, area 18 and posteromedial lateral suprasylvian area (PMLS) of young and old cats. We found that LGN cells in old cats exhibit largely normal visual response latency. ⋯ Area 18 slowed more than area 17, but this was not significant. The degradation of signal timing in the visual cortex might provide insight into neuronal response mechanism underlying perception slowing during aging.
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It has been documented that infection of herpes simplex virus type 1 (HSV-1) contributes to the initiation of Bell's palsy. However, the exact mechanisms responsible for this disorder have not been fully elucidated to date. A mouse model of facial palsy induced by HSV-1 provides an opportunity to investigate the alteration in activities of nuclear factor-kappa B (NF-κB) and its consequent effect on two key inflammatory factors, i.e., tumor necrosis factor (TNF)-α and cyclooxygenase-2 (COX-2), as well as the effect of glucocorticoids (GCs) in this work. ⋯ In addition, GCs inhibited the nuclear translocation and DNA binding activity of NF-κB via inhibiting IκB-α degradation. Meanwhile, TNF-α production and COX-2 expression were significantly reduced by GCs. In conclusion, HSV-1 inoculation induced the activation of NF-κB, expression and secretion of TNF-α and COX-2 in the facial paralyzed mice, while, glucocorticoid effectively down-regulated TNF-α and COX-2 expression in HSV-1-induced paralyzed mice.
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Two major neurotrophic factors, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are involved in a number of physiological processes associated with neuronal growth, survival and plasticity. There are an increasing number of papers demonstrating their ability to serve as neuroprotective molecules under various pathological conditions. At the same time, it remains unclear whether both NGF and BDNF have similar roles under pathological conditions and their effects on the electrophysiological properties of neurons after acute pathogen exposure. ⋯ One week after virus injection acute brain slices were incubated with beta-amyloid (25-35) for 1h and afterward in vitro LTP induction was performed in medial perforant path-DG synapses. We demonstrate that chronic elevation of NGF but not BDNF concentration protects LTP induction from beta-amyloid action. Further inhibitory analysis suggests that the effect of NGF is mediated by PI3K-signaling cascade.