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美国加利福尼亚大学欧文分校的神经科学家珍妮弗·切尔尼亚夫斯基和约翰·古佐夫斯基说，大脑炎症可以很快干扰我们提取类似但不同经历的复杂记忆的能力。 |
美国加利福尼亚大学欧文分校的神经科学家珍妮弗·切尔尼亚夫斯基和约翰·古佐夫斯基说，大脑炎症可以很快干扰我们提取类似但不同经历的复杂记忆的能力。
他们的研究成果发表在美国《神经科学学报》上。该研究弄清了免疫系统如何示意称为“细胞因子”的分子损害海马体中神经元之间的通信。海马体是大脑中的一个区域，它对于分辨记忆很重要。该研究有助于人们认识接受化疗的人和存在自身免疫疾病或神经组织退化疾病的人出现认知缺陷的原因。
古佐夫斯基说：“我们的研究首次在免疫系统活化、神经回路功能改变和受损的分辨记忆之间建立了联系。该研究的一些推论或许对多发性硬化症等慢性疾病的患者有益。这类患者会出现记忆缺损。该研究甚至对癌症患者也有好处。”
他认为，一个有趣现象是，海马体中“细胞因子”水平增加只会影响复杂分辨记忆，这种记忆能让我们区分大致上类似的经历，例如我们在工作时做了什么或晚餐吃了什么。由海马体处理的较简单的记忆形式——类似于记住你工作的地点——却没有因为大脑炎症而改变。
该研究或许还能让我们认识化疗相关的心智现象——“化疗脑”。遭遇“化疗脑”问题的癌症患者会难以有效处理信息。欧文分校的神经肿瘤学家发现，化疗会损害大脑中一些干细胞，这些干细胞本来会成长为用于创建和储存记忆的神经元。(来源：生物帮)
原文摘要：
Jennifer Czerniawski and John F. Guzowski
Although it is known that immune system activation can impair cognition, no study to date has linked cognitive deficits during acute neuroinflammation to dysregulation of task-relevant neuronal ensemble activity. Here, we assessed both neural circuit activity and context discrimination memory retrieval, in a within-subjects design, of male rats given systemic administration of saline or lipopolysaccharide (LPS). Rats were exposed over several days to two similar contexts: one of which was paired with weak foot shock and the other was not. After reaching criteria for discriminative freezing, rats were given systemic LPS or saline injection and tested for retrieval of context discrimination 6 h later. Importantly, LPS administration produced an acute neuroinflammatory response in dorsal hippocampus at this time (as assessed by elevation of proinflammatory cytokine mRNA levels) and abolished retrieval of the previously acquired discrimination. The impact of neuroinflammation on hippocampal CA3 and CA1 neural circuit activity was assessed using theArc/Homer1a cellular analysis of temporal activity by fluorescence in situ hybridization imaging method. Whereas the saline-treated subjects discriminated and had low overlap of hippocampal ensembles activated in the two contexts, LPS-treated subjects did not discriminate and had greater ensemble overlap (i.e., reduced orthogonalization). Additionally, retrieval of standard contextual fear conditioning, which does not require context discrimination, was not affected by pretesting LPS administration. Together, the behavioral and circuit analyses data provide compelling evidence that LPS administration impairs context discrimination memory by disrupting cellular pattern separation processes within the hippocampus, thus linking acute neuroinflammation to disruption of specific neural circuit functions and cognitive impairment.
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