The rodent olfactory bulb incorporates thousands of newly generated inhibitory neurons daily throughout adulthood, but the role of adult neurogenesis in olfactory processing is not fully understood. Here we adopted a genetic method to inducibly suppress adult neurogenesis and investigated its effect on behavior and bulbar activity. Mice without young adult-born neurons (ABNs) showed normal ability in discriminating very different odorants but were impaired in fine discrimination. Furthermore, two-photon calcium imaging of mitral cells (MCs) revealed that the ensemble odor representations of similar odorants were more ambiguous in the ablation animals. This increased ambiguity was primarily due to a decrease in MC suppressive responses. Intriguingly, these deficits in MC encoding were only observed during task engagement but not passive exposure. Our results indicate that young olfactory ABNs are essential for the enhancement of MC pattern separation in a task engagement-dependent manner, potentially functioning as a gateway for top-down modulation.

中文翻译：

---

成年神经元在任务参与过程中促进嗅球模式分离

在整个成年期，啮齿动物的嗅球每天都会包含数千个新生成的抑制性神经元，但成年神经发生在嗅觉处理中的作用尚不完全清楚。在这里，我们采用遗传方法来诱导抑制成体神经发生，并研究其对行为和延髓活动的影响。没有年轻成年神经元（ABN）的小鼠在辨别非常不同的气味方面表现出正常的能力，但在精细辨别方面受到损害。此外，二尖瓣细胞（MC）的双光子钙成像显示，在消融动物中，相似气味剂的整体气味表征更加模糊。这种模糊性的增加主要是由于 MC 抑制反应的减少。有趣的是，MC 编码中的这些缺陷仅在任务参与过程中观察到，而在被动暴露过程中则没有观察到。我们的结果表明，年轻的嗅觉 ABN 对于以任务参与依赖的方式增强 MC 模式分离至关重要，可能充当自上而下调制的网关。