Neuroscience
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Previously, we reported that in rats, GABA(A) and glycine receptor immunoreactivity increased markedly in multiple brain stem respiratory nuclei around postnatal days (P) 12-13, a critical period when abrupt neurochemical, metabolic, ventilatory, and electrophysiological changes occur in the respiratory network and when the system is under greater inhibition than excitation. Since Na(+)-K(+)-2Cl(-) co-transporter 1 (NKCC1) and K(+)-Cl(-) co-transporter 2 (KCC2) play pivotal roles in determining the responses of GABA(A) and glycine receptors, we hypothesized that NKCC1 and KCC2 undergo significant changes during the critical period. ⋯ Our data revealed that (1) NKCC1 immunoreactivity exhibited a developmental decrease from P0 to P21 in all eight nuclei examined, being relatively high during the first 1½ postnatal weeks and decreased thereafter. The decrease was abrupt and statistically significant at P12 in the PBC, Amb, and XII; (2) KCC2 immunoreactivity in these eight nuclei showed a developmental increase from P0 to P21; and (3) the significant reduction in NKCC1 and the greater dominance of KCC2 around P12 in multiple respiratory nuclei of the brain stem may form the basis of an enhanced inhibition in the respiratory network during the critical period before the system stabilizes to a more mature state.
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The cerebellar uvula (lobule IX), a part of the vestibulocerebellum, is extensively connected to the areas of the brainstem that participate in cardiovascular regulation and vestibular signal processing. This suggests that the uvula regulates blood pressure (BP) during postural alterations. Previous studies showed that lesions of the uvula affected the baroreceptor reflex and cardiovascular responses during postural alterations. ⋯ By contrast, photoinhibition had no statistically significant effect on BP recovery during head-up tilts. The effects of photoinhibition on BP during tilts were significantly different from those observed during the resting condition, indicating that cerebellar control of BP during tilts is dynamic rather than static. Taken together, these results suggest that PCs in the uvula dynamically regulates BP maintenance during postural alterations.
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We have previously reported that experimental mild traumatic brain injury results in increased sensitivity to stressful events during the first post-injury weeks, as determined by analyzing the hypothalamic-pituitary-adrenal (HPA) axis regulation following restraint-induced stress. This is the same time period when rehabilitative exercise has proven to be ineffective after a mild fluid-percussion injury (FPI). Here we evaluated effects of stress on neuroplasticity. ⋯ A suppression of MR was found at PID 1 in vehicle-treated FPI and Sham groups. Decreases in the precursor form of BDNF were observed in different FPI groups at PIDs 7 and 14. These findings suggest that the increased sensitivity to stressful events during the first post-injury weeks, after a mild FPI, has an impact on hippocampal neuroplasticity.
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In this article, we aimed to study whether feature precedence existed in the cognitive processing of multifeature visual information in the human brain. In our experiment, we paid attention to two important visual features as follows: color and shape. In order to avoid the presence of semantic constraints between them and the resulting impact, pure color and simple geometric shape were chosen as the color feature and shape feature of visual stimulus, respectively. ⋯ The experiment consisted of three tasks as follows: Color task, Shape task and Color-Shape task. The results showed that the feature-based pattern would be activated in the human brain in processing multifeature visual information without semantic association between features. Furthermore, shape feature was processed earlier than color feature, and the cognitive processing of color feature was more difficult than that of shape feature.
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The superior region of the precentral gyrus (preCG) is known to be actively involved with hand function and has been proposed as a possible neural correlate of handedness. To test this hypothesis, we used a combined voxel-based morphometric (VBM) asymmetry analysis of structural MRI, along with diffusion MRI (dMRI) tractography to investigate laterality indices of corticomotor white matter (WM) pathways, based on measures of fractional anisotropy (FA). The relationship between measures of motor performance and FA laterality indices was also investigated. ⋯ Furthermore, significant correlations were found between FA asymmetry measures projecting from this region, namely corticospinal tracts and those connecting the postcentral gyri, with grip strength and finger-tapping performance, respectively. A number of the motor pathways projecting from this region also exhibited leftward asymmetry of FA distributions. The findings from this study highlight the role of the left motor cortex in skilled motor performance and provide a framework for the study of the relationship between handedness and preCG hand representation in larger normative populations.