Synchronized Neural Input Shapes Stimulus Selectivity in a Collision-Detecting Neuron
Synchronized Neural Input Shapes Stimulus Selectivity in a Collision-Detecting Neuron
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DOI：
10.1016/j.cub.2010.10.025
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发表时间：
2010-11-23
期刊：
影响因子：
9.2
通讯作者：
Gabbiani, Fabrizio
中科院分区：
文献类型：
--
作者：
Jones, Peter W.;Gabbiani, Fabrizio
高阶感觉神经元如何从它们简单的输入中产生复杂的选择性是神经科学中的一个基本问题。小叶巨型运动检测器（LGMD）是美洲血吸虫（Schistocerca americana）中的一种视觉神经元，它选择性地对碰撞过程中接近的物体或其二维投影，隐约可见的刺激做出反应[1-4]为了研究这种选择性是如何产生的，我们设计了一种装置，允许我们刺激，单独地和独立地，类似于15，000个基本视觉输入的相当大的一部分以视网膜定位方式撞击到LGMD的树突扇[5-7]。（图1Ai）然后，我们在整个视觉通路中在体内细胞内记录，评估LGMD的活动和传递局部兴奋性输入的所有三个连续突触前阶段的活动。我们的结果表明，随着碰撞变得越来越迫在眉睫，这些输入的强度增加，而它们的等待时间减少。这种等待时间的减少有利于在整个逼近的序列中顺序激活的输入的总和，使得神经元对碰撞限制的轨迹最敏感。因此，LGMD的选择性部分来自突触前机制，它在即将到来的刺激期间同步大量的输入，随后由神经元自身内的突触后机制检测类似的机制可能也是其他物种视觉神经元调谐特性的基础
How higher order sensory neurons generate complex selectivity from their simpler inputs is a fundamental question in neuroscience The lobula giant movement detector (LGMD) is such a visual neuron in the locust Schistocerca americana that responds selectively to objects approaching on a collision course or their two-dimensional projections, looming stimuli [1-4] To study how this selectivity arises, we designed an apparatus allowing us to stimulate, individually and independently, a sizable fraction of the similar to 15,000 elementary visual inputs impinging retinotopically onto the LGMD s dendritic fan [5-7] (Figure 1Ai) We then recorded intracellularly in vivo throughout the visual pathway, assessing the LGMD's activity and that of all three successive presynaptic stages conveying local excitatory inputs Our results suggest that as collision becomes increasingly imminent, the strength of these inputs increases, whereas their latency decreases This latency decrease favors summation of inputs activated sequentially throughout the looming sequence, making the neuron maximally sensitive to collision-bound trajectories Thus, the LGMD s selectivity arises partially from presynaptic mechanisms that synchronize a large population of inputs during a looming stimulus and subsequent detection by postsynaptic mechanisms within the neuron itself Analogous mechanisms are likely to underlie the tuning properties of visual neurons in other species as well