Removing a single neuron in a vertebrate brain forever abolishes an essential behavior
Removing a single neuron in a vertebrate brain forever abolishes an essential behavior
复制标题
DOI：
10.1073/pnas.1918578117
复制
发表时间：
2020-02-11
影响因子：
11.1
通讯作者：
Schuster, Stefan
中科院分区：
文献类型：
--
作者：
Hecker, Alexander;Schulze, Wolfram;Schuster, Stefan
巨型莫特纳 (M) 细胞是脊椎动物大脑中已知的最大神经元。它在神经科学领域取得了重大突破，但其最终功能仍然令人惊讶地不清楚：M细胞介导的逃逸的实际生存价值从未得到实验支持，并且反复消融细胞未能消除所有快速逃逸，这表明逃逸同样可以由较小的神经元驱动。在这里，我们应用技术来同时测量巨轴突在体细胞消融后较长时间内的逃逸表现和状态。我们发现轴突存活时间非常长，并且仍然完全有能力驱动快速逃逸行为。通过单方面去除两个 Max 轴突之一，并比较同一个体中能够或不能招募 Max 轴突的逃逸情况，我们表明巨大的 Max 轴突对于快速逃逸至关重要，并且它的损失意味着快速逃逸也永远消失。这使我们能够直接测试 M 细胞介导的逃逸的生存价值，并证明这种巨型神经元的缺失直接影响在遇到自然捕食者时的生存。这些发现不仅为一个古老的难题提供了令人惊讶的解决方案，而且表明即使是复杂的大脑也可以信任单个神经元的重要功能。我们的研究结果表明，机制必须与这些神经元保持轴突存活和连接的独特意义同时进化。
The giant Mauthner (M) cell is the largest neuron known in the vertebrate brain. It has enabled major breakthroughs in neuroscience but its ultimate function remains surprisingly unclear: An actual survival value of M cell-mediated escapes has never been supported experimentally and ablating the cell repeatedly failed to eliminate all rapid escapes, suggesting that escapes can equally well be driven by smaller neurons. Here we applied techniques to simultaneously measure escape performance and the state of the giant M axon over an extended period following ablation of its soma. We discovered that the axon survives remarkably long and remains still fully capable of driving rapid escape behavior. By unilaterally removing one of the two M axons and comparing escapes in the same individual that could or could not recruit an M axon, we show that the giant M axon is essential for rapid escapes and that its loss means that rapid escapes are also lost forever. This allowed us to directly test the survival value of the M cell-mediated escapes and to show that the absence of this giant neuron directly affects survival in encounters with a natural predator. These findings not only offer a surprising solution to an old puzzle but demonstrate that even complex brains can trust vital functions to individual neurons. Our findings suggest that mechanisms must have evolved in parallel with the unique significance of these neurons to keep their axons alive and connected.