Neuroscience
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The comparative roles of the human amygdala and orbitofrontal cortex in emotional processing are under substantial debate, supported prominently by invasive primate studies. Noninvasive studies in humans are restricted by the limitations of electro- and magneto-encephalographic methods, which are hampered by the closed-field architecture and deep location of these structures. Here we employ whole-brain functional magnetic resonance imaging at an effective sampling rate of 300 ms to define the latency of enhanced blood oxygen level dependent (BOLD) contrast within structures activated by emotionally evocative relative to neutral scenes, in an effort to assess the hypothesized primacy of amygdala-inferotemporal co-activity in human emotional perception, relative to orbitofrontal cortex. ⋯ Subcortical structures including the amygdala, locus coeruleus, and basal forebrain also showed reliably increased activity during emotional scene perception. The latency at which emotional BOLD signal enhancement varied considerably across structures, ranging from 2 to 6 seconds after scene onset. Though coarse, the spatiotemporal pattern of emotion-enhanced activity identified here is consistent with the idea that the amygdala and inferior temporal fusiform gyrus are the first regions to discriminate scene emotionality, which may then distribute this categorical information to other cortical and subcortical structures.
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The article studies the effect of melatonin on the intensity of free radical oxidation, the functioning of the enzymatic components of the antioxidant system and their transcriptional regulation in rats with experimental cerebral ischemia/reperfusion of the brain. The development of ischemia/reperfusion was characterized by the activation of apoptotic processes and the accumulation of mRNA of the genes Sod1, Cat, Gpx1, Gsr, Hif-1α, Nrf2, Nfkb2, and Foxo1 in the rats' brains. ⋯ At the same time, there was a shift in the activity of superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, which increased in the presence of a pathology, towards the control values. The revealed changes may be accounted for by antioxidant and neuroprotective properties of melatonin, which provided a decrease in the degree of mobilization of the protective systems in animal organism.
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A secondary consequence of spinal cord injury (SCI) is debilitating chronic neuropathic pain, which is commonly morphine resistant and inadequately managed by current treatment options. Consequently, new pain management therapies are desperately needed. We previously reported that dopamine D3 receptor (D3R) dysfunction was associated with opioid resistance and increases in D1 receptor (D1R) protein expression in the spinal cord. ⋯ Following SCI, morphine + pramipexole and morphine + SCH 39166 significantly increased both thermal and mechanical thresholds. Morphine alone induced conditioned place preference, but when combined with either the D3R agonist or D1R antagonist preference was not induced. The data suggest that adjunct therapy with receptor-specific dopamine modulators can restore morphine analgesia and decrease reward potential and thus, represents a new target for pain management therapy after SCI.
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Profiling the Gene Expression and DNA Methylation in the Mouse Brain after Ischemic Preconditioning.
Ischemic preconditioning (IPC) is a phenomenon in which a short-term sublethal ischemic exposure induces tolerance to a subsequent lethal ischemic insult; however, the detailed mechanism underlying IPC-induced neuroprotection remains obscure. Here, we applied middle cerebral artery occlusion, a preconditioning ischemic insult mouse model, to investigate the molecular mechanism underlying cerebral IPC. RNA sequencing and whole-genome bisulfite sequencing were performed to explore the gene expression profile and DNA methylation changes after cerebral IPC treatment. ⋯ The involvement of several genes in IPC-induced neuroprotection was first reported. Genes induced by IPC, including Arid5a, Nptx2 and Stc2, demonstrated a neuroprotective effect against oxygen-glucose deprivation induced neurotoxicity in vitro. Thus, our findings provide new insights into IPC signaling pathways and offer a novel therapeutic strategy towards stroke.
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The over-activation of N-methyl-D-aspartate receptors (NMDARs) is the main cause of neuronal death in brain ischemia. Both the NMDAR and the Acid-sensing ion channel 1a (ASIC1a) are present in the postsynaptic membrane of the central nervous system (CNS) and participate in physiological and pathological processes. However, the specific role played by ASIC1a in these processes remains elusive. ⋯ Furthermore, brain infarct sizes were reduced by a greater degree in older mice compared to younger ones when ASIC1a activity was suppressed. These data suggest that ASIC1a activity selectively enhances the function of triheteromeric NMDARs and exacerbates ischemic neuronal death especially in older animal brains. We propose ASIC1a as a novel therapeutic target for preventing and reducing the detrimental effect of brain ischemia in humans.