Brain research
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Widespread brain gray matter (GM) atrophy is a normal part of the aging process. However, recent studies indicate that age-related GM changes are not uniform across the brain and may vary according to health status. Therefore the aims of this study were to determine whether chronic pain in temporomandibular disorder (TMD) is associated with abnormal GM aging in focal cortical regions associated with nociceptive processes, and the degree to which the cumulative effects of pain contributes to age effects. ⋯ Finally, a result of particular note is that after accounting for the effects of TMD duration, age remained as a significant predictor of GM in the PMC and dorsal striatum. Thus, abnormal GM aging in TMD may be due to the progressive impact of TMD-related factors in pain-related regions, as well as inherent factors in motor regions, in patients with TMD. This study is the first to show that chronic pain is associated with abnormal GM aging in focal cortical regions associated with pain and motor processes.
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Comparative Study
Longitudinal in-vivo diffusion tensor imaging for assessing brain developmental changes in BALB/cJ mice, a model of reduced sociability relevant to autism.
Diffusion tensor imaging (DTI) is highly sensitive in detecting brain structure and connectivity phenotypes in autism spectrum disorders (ASD). Since one of the core symptoms of ASD is reduced sociability (reduced tendency to seek social interaction), we hypothesized that DTI will be sensitive in detecting neural phenotypes that correlate with decreased sociability in mouse models. Relative to C57BL/6J (B6) mice, juvenile BALB/cJ mice show reduced sociability. ⋯ Significant differences in FA and MD values between BALB/cJ and B6 mice were observed in most white and gray matter areas at all three time points. Significant differences in developmental trajectories of FA and MD values from thalamus and frontal motor cortex were also observed between BALB/cJ and B6, indicating relative under-connectivity in BALB/cJ mice. These results indicate that DTI may be used as an in-vivo, non-invasive imaging method to assess developmental trajectories of brain connectivity in mouse models of neurodevelopmental and behavioral disorders.
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Matrine (Mat) and oxymatrine are two major alkaloids of the Chinese herb Sophora flavescens Ait. (Leguminosae). Previous study has demonstrated that Mat reduces brain edema induced by focal cerebral ischemia. More recently, oxymatrine has been reported to produce neuroprotective effects against focal cerebral ischemia via inhibiting the activation of NF-κB in the ischemic brain tissue. ⋯ Further observations revealed that Mat increased the protein levels of IκBα, and blocked the translocation of NF-κB p65 from the cytosol to the nucleus in the ischemic cortex and injured neurons and astrocytes induced by in vitro OGD. Moreover, Mat could down-regulate NF-κB p65 downstream pro-apoptotic gene p53 and/or c-Myc in the injured neurons and astrocytes induced by OGD. The present findings suggest that Mat, even when administrated 6h after ischemia, has neuroprotective effects against focal cerebral ischemia and directly protects neurons and astrocytes via inhibition of NF-κB signaling pathway, contributing to matrine's neuroprotection against focal cerebral ischemia.
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Adequate grip force modulation is critical to manual dexterity and often impaired in hemiparetic stroke patients. Previous studies in hemiparetic patients suggest that aspects of grip force control may be differently affected by the lesion. We developed a visuomotor power grip force-tracking task allowing quantification of tracking error, force variability and release duration. ⋯ Release duration, however, was increased (also in the non-paretic hand), was force-independent and did not correlate with MVC strength. Of the three performance measures, only release duration explained some of the variance in arm and hand function (Frenchay Arm Test score), independent of MVC strength. The findings show (i) that hemiparetic stroke patients preserve the ability to modulate (generate and maintain) power grip force within their limited force range and (ii) that MVC grip strength and duration of grip release are differently affected and are two complementary predictors of arm function after stroke.
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Ischemic stroke is one of the leading causes of mortality and disability worldwide. Our previous studies have shown that hyperbaric oxygen (HBO) preconditioning can afford significant neuroprotection against cerebral ischemia-reperfusion (I/R) injury in rats. However, it is still unknown whether HBO preconditioning can directly protect primary cultured cortical neurons against oxygen-glucose deprivation (OGD). ⋯ However, the cyclooxygenase (COX)-2 inhibitor NS-398 blocked the production of 15d-PGJ(2) in OGD-exposed neurons with HBO preconditioning. In addition, 15d-PGJ(2) preconditioning could also protect cultured neurons against OGD injury. These results demonstrate that HBO preconditioning has directly beneficial effects on ODG-exposed cortical neurons by the activation of PPAR γ subsequent to the production of 15d-PGJ(2), which in turn increases the downstream antioxidant enzymatic activities.