Neuroscience
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Oligodendrocyte progenitor cells (OPC) are glial cells that differentiate into myelinating oligodendrocytes during early stages of post-natal life. However, OPCs persist beyond developmental myelination and represent an important population of cycling cells in the gray and white matter of the adult brain. While adult OPCs form unique territories that are maintained through self-avoidance, some cortical OPCs appear to position their cell body very close to that of a neuron, forming what are known as OPC-neuron pairs. ⋯ Density of OPC-neuron pairs was increased by the GABAA receptor antagonist picrotoxin. Finally, histological analysis of OPC-neuron pairs suggested that in the dorsal portion of the cortex, GABAergic interneurons represent the most common neuronal component of the pairs, and that calbindin, calretinin and parvalbumin GABAergic interneurons found in the cortex take part in these pairs. Using previous estimates of the number of GABAergic neurons in the rodent cortex, we estimate that roughly one in four GABAergic neurons are paired with an OPC.
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Ski, as an evolutionarily conserved protein, is a versatile transcriptional regulator which widely distributes in various tissues and species. Recently, we have demonstrated for the first time that Ski was strikingly up-regulated in reactive astrocytes after spinal cord injury (SCI) in vivo, which indicates that maybe Ski is a new molecule that controls astrocytes' biological properties after SCI. However, the accurate distributions and functions of Ski in astrocytes after central nervous system (CNS) injury are still unclear. ⋯ Surprisingly, Ski knockdown also weakened the primary astrocyte migration. Based on the above, we could conclude that Ski might play a crucial role in astrocyte proliferation and migration. This discovery might contribute to a promising therapeutic intervention in CNS injury.
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The dysregulation of posttranslational modifications of the microtubule-associated protein (MAP) tau plays a key role in Alzheimer's disease (AD) and related disorders. Thus, we have previously shown that beta amyloid (Aβ)-induced neurotoxicity was mediated, at least in part, by tau cleavage into the tau45-230 fragment. However, the mechanisms underlying the toxicity of tau45-230 remain unknown. ⋯ Our results indicated that tau45-230 significantly reduced the number of organelles transported along hippocampal axons. This altered axonal transport did not correlate with changes in the total number of organelles present in these cells or in motor protein levels. Together these results suggested that tau45-230 could exert its toxic effects by partially blocking axonal transport along microtubules thus contributing to the early pathology of AD.
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Recent data suggest that manipulating the muscle afferents of one arm affects both ipsilateral and contralateral perceptual estimates. Here, we used the mirror paradigm to study the bimanual integration of kinesthetic muscle afferents. The reflection of a moving hand in a mirror positioned in the sagittal plane creates an illusion of symmetrical bimanual movement. ⋯ We found that as long as the arm was still moving, the kinesthetic illusion decayed slowly after visual occlusion. These findings suggest that the mirror illusion results from the combination of visuo-proprioceptive signals from the two arms and is not purely visual in origin. Our findings also support the more general concept whereby proprioceptive afferents are integrated bilaterally for the purpose of kinesthesia during bimanual tasks.
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The fact that interference from peripheral distracting information can be reduced in high perceptual load tasks has been widely demonstrated in previous research. The modulation from the perceptual load is known as perceptual load effect (PLE). Previous functional magnetic resonance imaging (fMRI) studies on perceptual load have reported the brain areas implicated in attentional control. ⋯ DC-PLE correlation analysis revealed that PLE was positively associated with the right middle temporal visual area (MT)-one of dorsal attention network (DAN) nodes. Furthermore, the right MT functionally connected to the conventional DAN and the RSFCs between right MT and DAN nodes were also positively associated with individual difference in PLE. The results suggest an important role of attentional control in perceptual load tasks and provide novel insights into the understanding of the neural correlates underlying PLE.