Department of Biology, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, USA.
Program in Neuroscience, Middlebury College, McCardell Bicentennial Hall, Middlebury, VT 05753, USA.
Neuroscience. 2023 Jul 15;523:105-117. doi: 10.1016/j.neuroscience.2023.05.018. Epub 2023 May 26.
Neurogenesis occurs throughout adulthood within the dentate gyrus, and evidence indicates that these new neurons play a critical role in both spatial and social memory. However, a vast majority of past research on adult neurogenesis has involved experiments with captive mice and rats, making the generalizability of results to natural settings questionable. We assessed the connection between adult neurogenesis and memory by measuring the home range size of wild-caught, free-ranging meadow voles (Microtus pennsylvanicus). Adult male voles (n = 18) were captured, fitted with radio collars, and released back into their natural habitat, where each vole's home range was assessed using 40 radio-telemetry fixes over the course of 5 evenings. Voles were then recaptured, and brain tissue was collected. Cellular markers of cell proliferation (pHisH3, Ki67), neurogenesis (DCX), and pyknosis were labeled on histological sections and then quantified using either fluorescent or light microscopy. Voles with larger home ranges had significantly higher pHisH3+ cell densities within the granule cell layer and subgranular zone (GCL + SGZ) of the dentate gyrus and higher Ki67+ cell densities in the dorsal GCL + SGZ. Voles with larger ranges also had significantly higher pyknotic cell densities in the entire GCL + SGZ and in the dorsal GCL + SGZ. These results support the hypothesis that cell proliferation and cell death within the hippocampus are involved with spatial memory formation. However, a marker of neurogenesis (DCX+) was not correlated with range size, suggesting that there may be selective cellular turnover in the dentate gyrus when a vole is ranging through its environment.
神经发生发生在成年的齿状回内，有证据表明这些新神经元在空间和社会记忆中都起着关键作用。然而，过去绝大多数关于成年神经发生的研究都涉及到对圈养的老鼠进行实验，这使得结果的普遍性对自然环境产生了质疑。我们通过测量野生捕获、自由放养的草地田鼠（Microtus pennsylvanicus）的家域大小来评估成年神经发生与记忆之间的联系。成年雄性田鼠（n=18）被捕获，佩戴无线电项圈，然后被释放回其自然栖息地，在 5 个晚上的过程中，通过 40 次无线电遥测固定点来评估每只田鼠的家域。然后重新捕获田鼠，并收集脑组织。使用荧光或光学显微镜对组织学切片上的细胞增殖标志物（pHisH3、Ki67）、神经发生标志物（DCX）和固缩进行标记，然后对其进行量化。家域较大的田鼠在齿状回的颗粒细胞层和颗粒下区（GCL+SGZ）中具有显著更高的 pHisH3+细胞密度和更高的 Ki67+细胞密度。家域较大的田鼠在整个 GCL+SGZ 和背侧 GCL+SGZ 中的固缩细胞密度也显著更高。这些结果支持这样的假设，即海马体中的细胞增殖和细胞死亡与空间记忆形成有关。然而，神经发生的标志物（DCX+）与范围大小无关，这表明当田鼠在其环境中活动时，齿状回中可能存在选择性的细胞更替。
