Neuroscience
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Amyloid plaque is a prominent pathologic hallmark in the brains of patients with Alzheimer's disease (AD), and it has been shown to be associated with endoplasmic reticulum (ER) stress response. However the precise regulation mechanism of amyloid-beta (Aβ) toxicity remains unclear. Here, we found that dauricine could activate X-box binding protein 1 (XBP-1; active form XBP-1S) and eukaryotic translation initiation factor eIF2α and thus delay the progression of AD in the Aβ1-42-transgenic Caenorhabditis elegans CL2120. ⋯ Our study reveals that dauricine activates the ire-1/xbp-1 and perk/eIF2α pathways of the unfolded protein response, attenuates translation, and enhances ER-associated degradation, which reduces Aβ expression and attenuates Aβ-associated toxicity. On the contrary, xbp-1 depletion counteracts the effects of dauricine on Aβ-associated toxicity. These results underscore the functional relevance of XBP-1 in Aβ toxicity and degradation, and highlight the potentially pharmacodynamic value of dauricine in preventing the progression of AD.
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Rhythmic actions are characterizable as a repeating invariant pattern of movement together with variability taking the form of cycle-to-cycle fluctuations. Variability in behavioral measures is atypically random, and often exhibits serial temporal dependencies and statistical self-similarity in the scaling of variability magnitudes across timescales. Self-similar (i.e. fractal) variability scaling is evident in measures of both brain and behavior. ⋯ The changes in hemodynamics were observed in both motor and sensorimotor cortical areas in the contralateral hemisphere. These results were observed only for the longer timescales of the detrended fluctuation analysis used to measure the exponent α. These findings suggest that complex auditory stimuli engage both brain and behavior at the level of variability scaling structures.
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Alterations in excitatory and inhibitory neurotransmitters (glutamate and GABA, respectively) have been found in various neuropsychiatric disorders, but have not been examined in individuals with prodigious cognitive abilities. Understanding exceptional brain processing is critical for developing biomedical interventions for cognitive and neurodevelopmental atypicalities. ⋯ We found substantially lower frontal glutamate/GABA compared to non-prodigy controls, but not glutamate or GABA individually, measured with magnetic resonance spectroscopy. We suggest that prefrontal glutamate/GABA is a potential marker of extraordinary cognitive skills.
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Oxytocin (OT) elicits weight loss in diet-induced obese (DIO) rodents, nonhuman primates, and humans, in part, by reducing food intake. Chronic OT administration produces more sustained weight loss in high-fat diet (HFD)-fed DIO rodents relative to chow-fed controls, but the reasons for this effect remain unclear. We hypothesized that HFD-induced obesity is associated with elevated OT receptor (OXTR) binding in brain regions where OT is known to cause decreased food intake and that this sensitized neural system is one mechanism by which OT preferentially elicits weight loss in DIO rodents. ⋯ Using quantitative receptor autoradiography, we found that (1) diet composition failed to alter OXTR or AVPR1a binding; (2) chronic OT treatment produced largely global reductions in forebrain OXTR and AVPR1a binding without significantly altering hindbrain OXTR binding. These findings suggest that forebrain OXTR and AVPR1a are down-regulated in response to chronic OT treatment. Given that chronic intranasal OT may be used as a therapeutic strategy to treat obesity, future studies should consider the potential downregulatory effect that chronic treatment can have across forebrain and hindbrain nonapeptide receptors and assess the potential contribution of both receptor subtypes to the outcome measures.
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Parkinson's disease (PD) is the second most common progressive neurodegenerative disorder and is characterized by loss of dopaminergic neurons. Biomarkers for tracking disease progression are useful indicators of the pathological conditions or the effects of therapeutic interventions on disease progression, but there are currently no known biomarkers in the blood that correlate with the progression of PD. Several studies have suggested that exosomes reflect intracellular changes that occur in response to pathological conditions and are an effective source of biomarkers for disease progression. ⋯ Fibrinogen gamma chain in plasma was also decreased in PD patients at HY stages II and III compared to healthy subjects. Therefore, these three exosomal proteins (clusterin, complement C1r subcomponent, and apolipoprotein A1) and fibrinogen gamma chain in plasma may be biomarker candidates for the diagnosis of PD. In particular, the expression levels of apolipoprotein A1 in exosomes may be useful for tracking the progression of PD.