Neuroscience
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The possibility that exposure to inhalation anaesthetics inhibits neurogenesis and results in memory deficits has attracted considerable interest over the past decade. This study was designed to investigate the mechanism of the sevoflurane exposure-induced decline in hippocampal neurogenesis. Young mice were anaesthetized with a gaseous mixture of 3.0% sevoflurane/60% oxygen 2 h daily for three consecutive days. ⋯ Concomitantly, BDNF and TrkB expression, which was decreased by sevoflurane, was also restored by NaB. Our study showed that sevoflurane affects long-term neurocognitive function and neurogenesis in young mice. Normalization of histone acetylation may alleviate the neurodevelopmental side effects of this anaesthetic.
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The rapid serial visual presentation (RSVP) paradigm seems to be one of the most appropriate for patients using P300-based brain-computer interface (BCI) applications, since non-ocular movements are required. However, according to previous works, the use of different locations for each stimulus may improve performance. Thus, the aim of the present work is to explore how spatial overlap between stimuli influences performance in controlling a visual P300-based BCI. ⋯ Significant differences in accuracy were found between the 0% overlapped condition and all the other conditions, and between 33.3% and higher overlap (66.7% and 100%). These results can be explained due to a modulation in the non-target stimulus amplitude signal caused by the overlapping factor. In short, the stimulus overlap provokes a modulation in performance using a P300-based BCI; this should be considered in future BCI proposals in which an optimal surface exploitation is convenient and potential users have only residual ocular movement.
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Some previous studies have demonstrated atypical brain lateralization in autism spectrum disorder (ASD). However, most of these reports have focused on language-related asymmetries in adults, and the developmental trajectory of hemispheric asymmetries in the important phase that occurs at 2-5 years of age remains unclear. Thus, we used structural magnetic resonance imaging and diffusion tensor imaging (DTI) in a longitudinal study of grey matter (GM) asymmetries across all cortical parcellation units (PUs) and white matter (WM) lateralization across the WM skeleton using voxel-based morphometry and tract-based spatial statistics (TBSS) in 34 toddlers with ASD and a matched group of 26 toddlers with developmental delay (DD) at 2-3 years old and with follow-up at 4-5 years of age. ⋯ GM lateralization was associated with the social and communicative disturbances observed in ASD at baseline, while WM asymmetry was significantly related to social disturbances and repetitive behaviours seen at 4-5 years of age. In conclusion, both ASD and DD toddlers had widespread rightward asymmetry, and the patterns of lateralization were similar across the groups. GM and WM showed asynchronous development of hemispheric asymmetries at 2-5 years of age, and this lateralization was associated with ASD symptoms.
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The mesopontine tegmental anesthesia area (MPTA) is a small brainstem nucleus that, when exposed to minute quantities of GABAA receptor agonists, induces a state of general anesthesia. In addition to immobility and analgesia this state is accompanied by widespread suppression of neural activity in the cerebral cortex and high delta-band power in the electroencephalogram. Collectively, MPTA neurons are known to project to a variety of forebrain targets which are known to relay to the cortex in a highly distributed manner. ⋯ Results indicated that double-labeling was rare, occurring on average in only 1.3% of the neurons sampled. The overwhelming majority of individual MPTA neurons showed specific connectivity, contributing to only one of the major ascending pathways, either ipsilaterally or contralaterally, but not bilaterally. This architecture would permit particular functional aspects of anesthetic loss-of-consciousness to be driven by specific subpopulations of MPTA neurons.
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As a non-limbic structure, the human thalamus is the most important modulator of the limbic system. The hypothalamus plays vital roles in the survival of species by regulating fear, learning, feeding behavior, circadian rhythm, sociosexual and reproductive activities of the limbic system through connections with the thalamus. The detailed anatomy of the pathways responsible for mediating these responses, however, is yet to be determined. ⋯ We studied 30 healthy human subjects. Using a high-resolution diffusion weighted tractography technique, for the first time, we were able to delineate and reconstruct the trajectory of the dorsal thalamo-hypothalamic tract (DTH). We further revealed the close relationship of the DTH, fornix and hippocampus in healthy adult human brain.