Neuroscience
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Spatial orientation necessitates the integration of visual and vestibular sensory cues, in-turn facilitating self-motion perception. However, the neural mechanisms underpinning sensory integration remain unknown. Recently we have illustrated that spatial orientation and vestibular thresholds are influenced by interhemispheric asymmetries associated with the posterior parietal cortices (PPC) that predominantly house the vestibulo-cortical network. ⋯ We observed that right-handed individuals experienced illusionary self-motion (vection) quicker than left-handers and that the degree of vestibular cortical dominance was correlated with the time taken to experience vection, only during conditions that induced interhemispheric conflict. To conclude, we demonstrate that interhemispheric asymmetries associated with vestibulo-cortical processing in the PPC functionally and mechanistically link sensory integration and self-motion perception, facilitating spatial orientation. Our findings highlight the importance of dynamic interhemispheric competition upon control of vestibular behavior in humans.
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Neuroinflammation plays an important role in epileptic disorders. Toll-like receptors (TLRs) are the key signal transduction tools by which neuroinflammation may promote epileptogenesis. Depending on the stimulus nature, TLRs may engage a distinct signaling pathway. ⋯ Pilocarpine induced profound hyperexcitability in the DG granule cells accompanied by potentiated excitatory postsynaptic currents (EPSCs) and dampened inhibitory postsynaptic currents (IPSCs), in contrast to the control group. However, pretreatment with TLR ligands preserved almost normal excitability and synaptic transmission against the pilocarpine. In conclusion, early activation of TLR4 and TLR2, probably through preserving normal hippocampal cytokine profile and neuronal function attenuates seizure severity in the rat model of TLE.
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Lipoxin A4 (LXA4) has been reported to reduce inflammation in experimental subarachnoid hemorrhage (SAH), but the mechanism remains unclear. In this study, we investigated the role of LXA4 in inflammation-mediated cerebrovascular endothelial dysfunction and the potential mechanism after SAH. SAH was induced by endovascular perforation in male Sprague-Dawley rats, and recombinant LXA4 was injected intracerebroventricularly 1.5 h after the operation. ⋯ The administration of LXA4 significantly ameliorated endothelial dysfunction, recovered microflow, and suppressed the inflammation and infiltration of neutrophils in SAH rats. The underlying mechanism of this outcome may involve the LXA4/FPR2/ERK1/2 pathway. LXA4 might be a promising candidate for acute SAH treatment.
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Cerebral small vessel disease (CSVD) is not only a cause of vascular dementia (VD) but also a contributing factor to Alzheimer's disease (AD). The essential pathological feature of CSVD is the disruption of blood-brain barrier (BBB). Dysfunction of BBB due to degeneration of both endothelial cells and pericytes in capillaries leads to neuronal damage and progressive brain atrophy. ⋯ Restoration of BBB function via remodeling of microvasculature and inhibition of Aβ accumulation could inhibit progressive brain atrophy and lead to restore cognitive dysfunction. Gene expression analysis indicated that infused MSCs activates both transforming growth factor-β and angiopoietin 1 signaling pathways and promotes the remodeling of microvasculature. Thus, infused MSCs may represent a novel therapy for both VD and AD.
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Defective cortical processing of visual stimuli and altered retinal function have been described in autism spectrum disorder (ASD) patients. In keeping with these findings, anatomical and functional defects have been found in the visual cortex and retina of mice bearing mutations for ASD-associated genes. Here we sought to investigate the anatomy and function of the adult retina of Engrailed 2 knockout (En2-/-) mice, a model for ASD. ⋯ In addition, En2-/- adult mice showed a significant reduction of photoreceptor (rhodopsin) and bipolar cell (Pcp2, PKCα) markers. Functional defects were also present in the retina of En2 mutants, as indicated by electroretinogram recordings showing a significant reduction in both a-wave and b-wave amplitude in En2-/- mice as compared to controls. These data show for the first time that anatomical and functional defects are present in the retina of the En2 ASD mouse model.