Transfer of visual motion information via graded synapses operates linearly in the natural activity range
Transfer of visual motion information via graded synapses operates linearly in the natural activity range
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DOI：
10.1523/jneurosci.21-17-06957.2001
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发表时间：
2001-09-01
影响因子：
5.3
通讯作者：
Egelhaaf, M
中科院分区：
文献类型：
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作者：
Kurtz, R;Warzecha, AK;Egelhaaf, M
用感觉刺激代替人工刺激突触前神经元，在体内研究了梯度电位神经元和尖峰神经元之间的突触传递。在视觉运动刺激过程中，电生理记录了果蝇脑内单个突触前和突触后神经元以及突触前钙（δ [Ca2+](pre)）浓度的变化。优先方向运动导致突触前神经元去极化。它也产生明显的增加[Ca2+]（前）和突触后尖峰率。相反方向的运动与突触前细胞的超极化有关，但只有[Ca2+]（前）和突触后尖峰率的微弱减少。除了这种纠正，突触前去极化，δ [Ca2+]（前）和突触后尖峰率之间的关系，平均而言，在整个活动水平范围内，可以由感觉刺激引起。因此，不可避免的有限范围内，整个突触信号传递的增益是恒定的，似乎被调整到感觉输入强度。
Synaptic transmission between a graded potential neuron and a spiking neuron was investigated in vivo using sensory stimulation instead of artificial excitation of the presynaptic neuron. During visual motion stimulation, individual presynaptic and postsynaptic neurons in the brain of the fly were electrophysiologically recorded together with concentration changes of presynaptic calcium (Delta [Ca2+](pre)). Preferred-direction motion leads to depolarization of the presynaptic neuron. It also produces pronounced increases in [Ca2+](pre) and the postsynaptic spike rate. Motion in the opposite direction was associated with hyperpolarization of the presynaptic cell but only a weak reduction in [Ca2+](pre) and the postsynaptic spike rate. Apart from this rectification, the relationships between presynaptic depolarizations, Delta [Ca2+](pre), and postsynaptic spike rates are, on average, linear over the entire range of activity levels that can be elicited by sensory stimulation. Thus, the inevitably limited range in which the gain of overall synaptic signal transfer is constant appears to be adjusted to sensory input strengths.