空間的感覺

2022年8月25日

信貸:傑米街/ Unsplash 2022年8月25日,也就不足為奇了環境的地圖是大腦最強大的記憶之一。所以他們是不可磨滅的,他們通常用作助記設備。然而,對神經和基因活動模式驅動和同步是由這些強大的記憶痕跡,編碼的地圖我們涉足的地方。在發表在《自然》雜誌的一項新研究中,科學家們測量了海馬的神經元的活動用鈣成像,同時監測基因表達在老鼠身上進行虛擬現實任務所需的空間學習,發現一種neurogenetic機製,大腦的形狀和穩定空間地圖。multi-lab科學家之間的合作研究,哈佛醫學院Blavatnik學院(HMS),確定一個叫做”叢書轉錄因子的表達幫助大腦使用專門的細胞和代碼的地方,創建和鞏固空間地圖。發現可以借新見解空間映射的機製,這些機製的破壞患者遭受大腦損傷,或神經退化。神經生物學教授邁克爾•格林伯格博士(右)和克裏斯托弗·哈維,博士,副教授,哈佛醫學院神經生物學(左),這項研究的資深作者。這項研究的資深作者,克裏斯托弗•哈維博士,神經生物學副教授HMS,說:“這個研究連接在不同水平的理解做出漂亮的分子之間的直接聯係和功能電路的行為和記憶的形成和穩定空間地圖。“海馬體對於學習和記憶是至關重要的,包括空間記憶的形成在老鼠和人類。早期的研究建立了“細胞”的存在在海馬體,激活和停用選擇性地當一個動物從事導航構建心理地圖的空間。哈維說:“多年來我的實驗室研究空間導航,包括地方細胞如何形成環境和形成空間記憶的地圖。 The molecular mechanisms that underlie those processes have been difficult to study in the behaving animal.” Harvey’s team, including lead author and research fellow Noah Pettit, and graduate student Lynn Yap, collaborated with Michael Greenberg, PhD, a professor of neurobiology at HMS, whose lab studies Fos activity. Earlier work from Greenberg’s team showed that minutes after a neuron is activated, it expresses Fos. Their work also showed Fos mediates different types of neural plasticity—the capacity of neurons to change structurally and functionally, including plasticity accompanying spatial learning and memory. However, whether Fos-expressing hippocampal neurons also encode spatial maps and whether Fos expression was associated with or influenced spatial coding was unclear. Harvey said, “There have been a lot of studies on Fos and place cells, but this is one of the first papers that directly connect the two.” In what Greenberg called a “technical tour de force,” Pettite and the team used a 360° virtual reality maze, developed in Harvey’s lab together with calcium imaging and gene expression measures to investigate the role of Fos expression in enlisting the activity of place cells. They found, within hours of performing a navigation task, hippocampal neurons in mice with high Fos expression were more likely to form accurate “place fields”—clusters of place cells that signal spatial position—than those with low Fos expression. Neurons with high Fos expression also formed place fields that were more reliable over time in indicating spatial position as the mouse repeated the same task on subsequent days. In addition, they found eliminating Fos expression in a subset of neurons in the hippocampus reduced the accuracy and stability of spatial maps compared to neurons with normal Fos expression. “This tells us that on a moment-to-moment basis as the mouse is navigating, the neurons that induce Fos have very robust information about the mouse’s spatial position, which is the key variable needed to solve and remember the task,” said Pettit. “Fos seems to be important for maintaining the stability and accuracy of place cells and representing a spatial map in the brain over time,” added Greenberg. These findings open new avenues of investigation. In future experiments, Harvey is interested in probing how Fos may help establish spatial memories during sleep, while Greenberg plans to investigate how Fos helps the brain form and maintain stable spatial maps and understand the function of Fos when spatial memories are transferred from the hippocampus to other regions of the brain. TAGS