Neuroscience
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A spontaneous mutation of the disrupted in schizophrenia 1 (Disc1) gene is carried by the 129S inbred mouse strain. Truncated DISC1 protein in 129S mouse synapses impairs the scaffolding of excitatory postsynaptic receptors and leads to progressive spine dysgenesis. In contrast, C57BL/6 inbred mice carry the wild-type Disc1 gene and exhibit more typical cognitive performance in spatial exploration and executive behavioral tests. ⋯ Analysis of pyr/int connectivity revealed a significant delay in synaptic transmission for 129S putative pairs. Sampled 129S pyr/int pairs also had lower detectability index scores than B6 putative pairs. Therefore, the spontaneous Disc1 mutation in the 129S strain attenuates the firing of putative pyr CA1 neurons and impairs spike timing fidelity during cognitive tasks.
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NMDA-type glutamate receptors play a critical role in activity-dependent neurite growth. We employed cell type-specific genetic labeling in zebrafish to examine the effects of NMDA receptor antagonism on the morphological development of tectal pyramidal neurons (PyrNs). ⋯ Axons that synapse with PyrNs, but not on spines, are unaffected by MK801 treatment. These findings may reflect different roles for NMDARs during the development of spiny and aspiny dendrites.
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The widespread application of ionizing radiation in industrial and medical fields leads to the increased brain exposure to X-rays. Radiation brain injury (RBI) seriously affects health of patients by causing cognitive dysfunction and neuroinflammation. However, the link between X-ray exposure and depressive symptoms and their detailed underlying mechanisms have not been well studied. ⋯ Moreover, X-ray exposure increased the expression of HMGB1, activated NLRP3 inflammasome signaling pathway and microglial cells, and then facilitated the release of pro-inflammatory cytokines, resulting in the pyroptosis and neuron loss both in vivo and in vitro. Additionally, glycyrrhizin (Gly), which is a HMGB1 inhibitor, reversed X-ray-induced behavioral changes and neuronal damage. Our findings indicated that HMGB1-mediated pyroptosis was involved in radiation-induced depression.
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Affective disorders (i.e. anxiety and depression) are commonly observed in patients with epilepsy and induce seizure aggravation. Animal models of epilepsy that exhibit affective disorder features are essential in developing new neuromodulatory treatments. GEAS-W rats (Generalized Epilepsy with Absence Seizures, Wistar background) are an inbred model of generalized epilepsy showing spontaneous spike-wave discharges concomitant with immobility. ⋯ We observed a main effect of treatment and a significant treatment by strain interaction on anxiety-like and depressive-like behaviours, with active-tDCS GEAS-W rats entering the center of the open field more often and showing less immobility in the forced swimming test. Furthermore, there was a main effect of treatment on corticosterone with active-tDCS animals showing marked reduction in plasmatic levels. This study described preclinical evidence to support tDCS treatment of affective disorders in epilepsy and highlights corticosterone as a possible mechanism of action.
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Several event-related potentials (ERPs) are associated with the processing of valence-dependent augmented feedback during the practice of motor tasks. In this study, 38 students learned a sequential arm-movement-task with 192 trials in each of five practice sessions (960 practice trials in total), to examine practice-related changes in neural feedback processing. Electroencephalogram (EEG) was recorded in the first and last practice session. ⋯ A valence-independent increase of the P300 amplitude after practice might reflect an improved ability to update the internal representation based on feedback information. These results demonstrate that valence-dependent neural feedback processing changes with extensive practice of a novel motor task. Dissociating changes in latencies of different components support the assumption that they are related to distinct mechanisms of feedback-dependent learning.