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Attention helps us process potentially important objects by selectively increasing the activity of sensory neurons that represent the relevant locations and features of our environment. This selection process requires top-down feedback about what is important in our environment. We investigated how parietal cortical output influences neural activity in early sensory areas. Neural recordings were made simultaneously from the posterior parietal cortex and an earlier area in the visual pathway, the medial temporal area, of macaques performing a visual matching task. When the monkey selectively attended to a location, the timing of activities in the two regions became synchronized, with the parietal cortex leading the medial temporal area. Parietal neurons may thus selectively increase activity in earlier sensory areas to enable focused spatial attention. 相似文献
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Selective attention mechanisms route behaviorally relevant information through large-scale cortical networks. Although evidence suggests that populations of cortical neurons synchronize their activity to preferentially transmit information about attentional priorities, it is unclear how cortical synchrony across a network is accomplished. Based on its anatomical connectivity with the cortex, we hypothesized that the pulvinar, a thalamic nucleus, regulates cortical synchrony. We mapped pulvino-cortical networks within the visual system, using diffusion tensor imaging, and simultaneously recorded spikes and field potentials from these interconnected network sites in monkeys performing a visuospatial attention task. The pulvinar synchronized activity between interconnected cortical areas according to attentional allocation, suggesting a critical role for the thalamus not only in attentional selection but more generally in regulating information transmission across the visual cortex. 相似文献
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猪细小病毒是引起母猪繁殖障碍性疾病的主要病原体之一,对猪细小病毒的基因组、转录、编码的结构蛋白和非结构蛋白、转录的调控及血清学诊断、分子生物学检测技术方面的研究进展予以综述,以期对其进一步研究有参考价值。 相似文献
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《农产品质量安全法》的颁布和实施,标志着我国农产品质量安全监管工作进入新阶段,兽药作为保障动物性产品安全的农产品生产过程中的重要投入品,其监管工作尤其令人关注。作者曾在基层挂职从事兽药监管工作,对我国兽药监管体系建设,尤其是市县级兽药监管现状十分担忧。特撰文阐述了兽药及兽药监管工作的重要性,分析了目前我国兽药及监督管理体系现状、面临的任务及存在问题,指出了我国市县级兽药监管系统存在监管主体不明确、监管体系不健全、行政管理和执法能力较弱、经费保障机制不到位、队伍素质不高、宣传培训不够等问题,并对此提出了解决问题的建议与对策。各级农牧部门应借兽医管理体制改革的东风,加强监督管理体系建设,进一步加强兽药监督队伍建设,加大兽药监督工作的经费支持力度,切实加强兽药监督管理工作。[编者按] 相似文献
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转基因生物是指通过基因操作技术对遗传物质(DNA)进行重组、修饰,从而改变基因组构成的动物、植物、微生物。动物用转基因微生物产品主要是指经过人工修饰基因的疫苗、诊断试剂和饲料添加微生物。转基因技术打破了异种微生物之间天然杂交的屏障,实现了微生物间的基因转移,获得了新的生物学性状。基因重组技术为人类有效的利用微生物的遗传特性, 相似文献
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