Neuroscience
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The hippocampus proper and the subiculum contain two major populations of somatostatin (SST)-containing interneurons, oriens-lacunosum moleculare (O-LM) cells projecting from the stratum oriens to the stratum lacunosum moleculare and bistratified cells with their cell bodies close to the pyramidal cell layer and axons terminating in the strata radiatum and oriens. Both types of interneurons innervate pyramidal cell dendrites and exert prominent feedback inhibition. We now investigated whether impairing this type of feed-back inhibition by selectively inhibiting GABA release from SST expressing interneurons in hippocampal sector CA1 and subiculum may be sufficient to induce spontaneous recurrent seizures. ⋯ Nine out of eleven mice within 10 days developed series of pre- or interictal spikes (IS, 21.4 ± 6.83 per week) and four mice exposed recurrent spontaneous seizures (SRS, 1.5 ± 0.29 per week). All 23 SRS observed were preceded by IS series. Our data demonstrate a critical role of feed-forward inhibition mediated by SST-containing interneurons suggesting that their sustained malfunctioning can be causatively involved in the development of TLE.
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Brain EGR1 (early growth response protein 1) overexpression aggravates focal ischemic brain injury, but its role in intracerebral hemorrhage (ICH) induced cerebral injury remains obscure. In this study, a rat ICH model was established by injecting type VII collagenase into the brain, and EGR1 knockdown reversed the increase of hematoma area, neurological function score, brain water content, blood-brain barrier (BBB) permeability, inflammation, p300 and retinoid a X receptor-α (RXRα) protein levels, as well as RXRα acetylation level induced by ICH. EGR1 expression was up-regulated in primary brain microvascular endothelial cells (BMECs), neurons, and astrocytes after ICH induction, and the up-regulation was most significant in BMECs. ⋯ Furthermore, the STAT3/NF-κB pathway was activated after treatment with OGD plus hemin, which was suppressed by silencing EGR1. Treatment with Stattic (an inhibitor of STAT3) restrained the effect of OGD plus hemin on NF-κB pathway activity, inflammation, cell viability and TEER. In conclusion, EGR1 increased RXRα acetylation level by regulating p300, thereby aggravating brain damage in ICH rat model and dysfunction in BMECs, Through the STAT3/NF-κB pathway.
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This study investigates the error processing components in the EEG signal of Performers and Observers using an auditory lexical decision task, in which participants heard spoken items and decided for each item if it was a real word or not. Pairs of participants were tested in both the role of the Performer and the Observer. In the literature, an Error Related Negativity (ERN)-Error Positivity (Pe) complex has been identified for performed (ERN-Pe) and observed (oERN-oPe) errors. ⋯ Our hypothesis regarding the ERN was not supported, however a Pe-like effect, as well as a P300 were present. Analyses to disentangle lexical and error processing similarly indicated a P300 for errors, and the results furthermore pointed to differences between responses before and after word offset. The findings are interpreted as marking attention during error processing during auditory word recognition.
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The prediction of the sensory consequences of physical movements is a fundamental feature of the human brain. This function is attributed to a forward model, which generates predictions based on sensory and efferent information. The neural processes underlying such predictions have been studied using the error-related negativity (ERN) as a fronto-central event-related potential in electroencephalogram (EEG) tracings. ⋯ The findings suggest that early in learning, the motor control system relies more on information from external feedback about terminal outcome. With increasing task performance, the forward model is able to generate more accurate outcome predictions, which, as a result, increasingly contributes to error processing. The data also suggests a complementary relationship between the ERN and the FRN over motor learning.