Neuroscience
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To mimic the expected pathological changes of white matter lesions (WMLs) and increase the stability, we applied modified two-vessel occlusion (modified 2VO) (1-week interval bilateral carotid artery occlusion) in stroke-prone renovascular hypertensive rats (RHRSP) and established a modified WMLs model (RHRSP/modified 2VO) that compared their phenotypes with RHRSP and sham-operated rats. In addition, we tried to differentiate small veins from small arteries through the presence of smooth muscle to study the pathological changes of small veins detailed in the model. RHRSP/modified 2VO rats showed higher stability and more extensive white matter damage without an obvious increase in mortality rate at 12 weeks after the modified 2VO operation compared to RHRSP rats. ⋯ In addition, RHRSP/modified 2VO rats possessed cognitive impairment, mild wall thickness and blood-brain barrier disruption. Our findings suggest that the modified WMLs model (RHRSP/modified 2VO) mimics cognitive impairment and small vessel pathological changes similar to WMLs in humans. Differentiating small veins from small arteries through smooth muscle is feasible, and marked small venous deposition may play an important role in the hypertensive white matter lesions.
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The assessment of binge ethanol-induced neuronal activation, using c-Fos immunoreactivity (IR) as a marker of neuronal activity, is typically accomplished via forced ethanol exposure, such as intraperitoneal injection or gavage. Neuronal activity using a voluntary binge-like drinking model, such as "drinking-in-the-dark" (DID), has not been thoroughly explored. Additionally, studies assessing ethanol-elicited neuronal activation may or may not involve stereotaxic surgery, which could impact c-Fos IR. ⋯ Relative to water-consuming controls, mice with BECs ≥ 80 mg/dl showed significantly elevated c-Fos IR in several brain regions implicated in neurobiological responses to ethanol. In general, the brain regions exhibiting binge-induced c-Fos IR were the same between studies, though differences were noted, highlighting the need for caution when interpreting ethanol-induced c-Fos IR when subjects have a prior history of surgery. Altogether, these results provide insight into the brain regions that modulate binge-like ethanol intake stemming from DID procedures among animals with and without surgery experience.
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Speech sound disorder (SSD) is common, yet its neurobiology is poorly understood. Recent studies indicate atypical structural and functional anomalies either in one hemisphere or both hemispheres, which might be accompanied by alterations in inter-hemispheric connectivity. Indeed, abnormalities of the corpus callosum - the main fiber tract connecting the two hemispheres - have been linked to speech and language deficits in associated disorders, such as stuttering, dyslexia, aphasia, etc. ⋯ Here, we investigated whether a sample of 18 children with SSD differed in callosal morphology from 18 typically developing children carefully matched for age. Significantly reduced dimensions of the corpus callosum, particularly in the callosal anterior third, were observed in children with SSD. These findings indicating pronounced callosal aberrations in SSD make an important contribution to an understudied field of research and may suggest that SSD is accompanied by atypical lateralization of speech and language function.
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Non-invasive brain stimulation is widely used to investigate and manipulate specific brain functions to broaden knowledge about healthy people, and also to provide for a potential treatment option for people with various psychopathological disorders that do not adequately benefit from traditional treatments. Nevertheless, the underlying mechanisms have not been fully investigated yet. The aim of the present study was to investigate whether we could alter the brain activity during a test for executive functioning. ⋯ Instead, we found a significant increase in deoxygenated hemoglobin [HHb] while performing the control task in the left anodal/right cathodal stimulation group compared to sham. Interestingly, also an influence on the mood of our participants was observed. These results are of importance especially regarding a better understanding of the influence of the dlPFC on the VFT.
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Xanthurenic acid (XA), formed from 3-hydroxykynurenine (3-HK) in the kynurenine pathway of tryptophan degradation, may modulate glutamatergic neurotransmission by inhibiting the vesicular glutamate transporter and/or activating Group II metabotropic glutamate receptors. Here we examined the molecular and cellular mechanisms by which 3-HK controls the neosynthesis of XA in rat, mouse and human brain, and compared the physiological actions of 3-HK and XA in the rat brain. In tissue homogenates, XA formation from 3-HK was observed in all three species and traced to a major role of kynurenine aminotransferase II (KAT II). ⋯ The effect of 3-HK was reduced in the presence of the KAT inhibitor aminooxyacetic acid. Finally, both 3-HK and XA reduced the power of gamma-oscillatory activity recorded from the hippocampal CA3 region. Endogenous XA, newly formed from 3-HK, may therefore play a physiological role in attentional and cognitive processes.