A synaptic mechanism for temporal filtering of visual signals.
A synaptic mechanism for temporal filtering of visual signals.
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DOI：
10.1371/journal.pbio.1001972
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发表时间：
2014-10
期刊：
影响因子：
9.8
通讯作者：
Lagnado L
中科院分区：
文献类型：
--
作者：
Baden T;Nikolaev A;Esposti F;Dreosti E;Odermatt B;Lagnado L
突触体积很重要！视网膜双极细胞突触前区室的大小控制着突触传递的幅度、速度和适应性。视觉系统通过不同的神经通路传递有关光强度快速和缓慢变化的信息。我们使用体内成像来研究双极细胞如何将这些信号传递到内层视网膜。我们发现，突触终端的体积是一个内在的属性，有助于不同的时间过滤器。单个细胞通过大小不同的多个终端传输，但较小的终端产生更快，更大的钙瞬变触发囊泡释放具有较高的初始增益，其次是更深刻的适应。较小的终端更有效地传输较高的刺激频率。模拟全球钙动力学触发囊泡释放表明，突触前区室的体积的变化直接导致所有这些差异的反应动力学。这些结果表明，一个神经元可以通过不同的适应特性不同的几何形状的突触终端传输不同的时间成分的视觉信号。神经传递的过程涉及电信号转化为神经元突触末端释放的化学神经递质，而这种释放的关键触发因素是钙浓度的升高。因此，这种钙信号的幅度和速度控制突触通信的幅度和时程。在鱼类视网膜双极细胞的突触终末上，我们发现突触前钙信号和随后的神经递质释放是由突触体积的基本性质决定的。使用实验方法和计算模型的组合，我们发现，大突触是缓慢的，在持续刺激过程中适应很少，而小突触是快速的，并显示出更深刻的适应。这一观察引出了第二个关键概念：由于神经元通常有几个突触前末梢，它们的体积可能不同，因此原则上，单个神经元可以将不同的突触信号转发给不同的突触后伙伴。我们提供的直接证据表明，这是鱼视网膜的双极细胞的情况。
Synaptic volume matters! The size of the presynaptic compartment of retinal bipolar cells controls the amplitude, speed, and adaptation of synaptic transmission. The visual system transmits information about fast and slow changes in light intensity through separate neural pathways. We used in vivo imaging to investigate how bipolar cells transmit these signals to the inner retina. We found that the volume of the synaptic terminal is an intrinsic property that contributes to different temporal filters. Individual cells transmit through multiple terminals varying in size, but smaller terminals generate faster and larger calcium transients to trigger vesicle release with higher initial gain, followed by more profound adaptation. Smaller terminals transmitted higher stimulus frequencies more effectively. Modeling global calcium dynamics triggering vesicle release indicated that variations in the volume of presynaptic compartments contribute directly to all these differences in response dynamics. These results indicate how one neuron can transmit different temporal components in the visual signal through synaptic terminals of varying geometries with different adaptational properties. The process of neurotransmission involves the conversion of electrical signals into the release of a chemical neurotransmitter from the neurons synaptic terminal, and the key trigger for this release is a rise in calcium concentration. Accordingly, the amplitude and speed of this calcium signal controls the amplitude and time-course of synaptic communication. Working on the synaptic terminals of fish retinal bipolar cells, we show that the presynaptic calcium signal and the subsequent neurotransmitter release are shaped by the basic property of synapse volume. Using a combination of experimental approaches and computational models, we found that large synapses are slow and adapt little during ongoing stimulation, while small synapses are fast and show more profound adaptation. This observation leads to a second key concept: since neurons usually have several presynaptic terminals that may vary in volume, a single neuron can, in principle, forward different synaptic signals to different postsynaptic partners. We provide direct evidence that this is the case for bipolar cells of the fish retina.
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影响因子：
64.8
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影响因子：
16.2
作者：
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通讯作者：
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DOI：
10.1073/pnas.0501961102
发表时间：
2005-07-26
影响因子：
11.1
作者：
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通讯作者：
Lagnado, L
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