Neuroscience
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Conduct disorder (CD) is a developmental disorder defined by a repetitive and persistent display of antisocial and aggressive behaviors that violates the rights of others or basic social rules. Recently, resting-state functional magnetic resonance imaging (rsfMRI) has been widely adopted to investigate the altered intrinsic neural activities and the disrupted endogenous brain connectivity of CD. In this study, functional connectivity density (FCD) mapping, a newly developed ultrafast voxel-wise method based on rsfMRI, was applied for the first time to examine the changes in the brain functional connectivity in CD at the voxel level. ⋯ We discovered that compared to healthy controls, CD patients showed increased short-range FCD in the default-mode network including the bilateral posterior cingulate cortex (PCC) and the bilateral precuneus (PCUN). More importantly, increased short-range FCD values in the bilateral PCC, the bilateral PCUN, and increased long-range FCD values in the left MCC showed significant correlations with the impulsivity. Overall, these results suggested that the FCD abnormalities in CD patients occurred in brain regions known to be involved in cognition, emotion and visual perception.
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The prefrontal cortex and the amygdala are critical for the emotional guidance of behavior and are believed to be a site of action for many anxiolytics and anxiogenics. Despite extensive studies examining how these drugs affect behavior, there is little information regarding their effects on neuronal activity. Additionally, with recent recognition of anxiety as a non-motor symptom of Parkinson's disease, it is unknown if activity in the cortex and the amygdala is altered. ⋯ On the other hand, yohimbine treatment (5mg/kg, SubQ) coincided with lower neuronal spiking activity compared to controls in the BLA of sham-lesioned rats, but was unchanged from controls in hemiparkinsonian rats. Yohimbine did not affect ACC neuronal spiking activity in either group. Overall, the lack of ACC responsiveness to diazepam in hemiparkinsonian, but not sham-lesioned rats underscores a plausible fundamental difference in anxiety-related neural signaling between animal groups.
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Glioma, one of the most common cancers in human, is classified to different grades according to the degrees of malignancy. Glioblastoma (GBM) is known to be the most malignant (Grade IV) whereas low-grade astrocytoma (LGA, Grade II) is relatively benign. The mechanism underlying the pathogenesis and progression of glioma malignancy remains unclear. ⋯ Interaction network analysis indicated that the GBM-associated proteins in the RNA processing were linked to crucial signaling transduction modulators including epidermal growth factor receptor (EGFR), signal transducer and activator of transcription 1 (STAT1), and mitogen-activated protein kinase 1 (MAPK1), which were further connected to the proteins important for neuronal structural integrity, development and functions. Upregulation of 40S ribosomal protein S5 (RPS5), Ferritin Heavy chain (FTH1) and STAT1, and downregulation of tenascin R (TNR) were validated as representatives by immune assays. In summary, we revealed a panel of GBM-associated proteins and the important modulators centered at the RNA-processing network in glioma malignancy that may become novel biomarkers and help elucidate the underlying mechanism.
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Diphtheria toxin (DT) administration into transgenic mice that express the DT receptor (DTR) under control of specific promoters is often used for cell ablation studies in vivo. Because DTR is not expressed in mice, DT injection has been assumed to be nontoxic to cells in vivo. In this study, we demonstrated that DT application during the juvenile stage leads to hearing loss in wild-type mice. ⋯ Histological studies demonstrated that hearing loss was accompanied by significant degeneration of inner and outer hair cells (HCs), as well as spiral ganglion neurons. Scanning electron microscopy showed quick degeneration of inner HCs within 3days and gradual degeneration of outer HCs within 1week. These results demonstrated that DT has ototoxic action on C57BL/6 mice during the juvenile period, but not thereafter, and the hearing loss was due to degeneration of inner and outer HCs by unknown DT-related mechanisms.
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Transgenic knock-in (KI) mice that express CaV2.1 channels containing an R192Q gain-of-function mutation in the α1A subunit known to cause familial hemiplegic migraine type-1 in patients, exhibit key disease characteristics and provide a useful tool to investigate pathophysiological mechanisms of pain transduction. Previously, KI trigeminal sensory neurons were shown to exhibit constitutive hyperexcitability due to up-regulation of ATP-gated P2X3 receptors that trigger spike activity at a more negative threshold. This implies that intrinsic neuronal conductances may shape action potential generation in response to ATP, which could act as a mediator of migraine headache. ⋯ In KI TG neurons, HCN2 subunits were predominantly present in the cytoplasm, not at the plasma membrane, likely accounting for the smaller Ih of such cells. ZD7288 hyperpolarized the membrane potential, thereby raising the firing threshold, and prolonging the spike trajectory to generate fewer spikes due to P2X3 receptor activation. The low amplitude of Ih in KI TG neurons suggests that down-regulation of Ih current in sub-threshold behavior acts as a compensatory mechanism to limit sensory hyperexcitability, manifested under certain stressful stimuli.