Octopaminergic modulation of contrast sensitivity.
Octopaminergic modulation of contrast sensitivity.
复制标题
DOI：
10.3389/fnint.2012.00055
复制
发表时间：
2012
影响因子：
3.5
通讯作者：
Nordström K
中科院分区：
文献类型：
--
作者：
de Haan R;Lee YJ;Nordström K
感觉系统通过降低对连续刺激的反应来适应长时间的刺激。鉴于视觉运动适应传统上已经在固定动物中进行了研究，最近的工作表明，动物的行为状态影响高阶运动视觉敏感神经元的响应特性。在昆虫飞行过程中，章鱼胺被释放，并且药理学章鱼胺能激活可以诱导虚构的运动状态。在昆虫视神经节，小叶板切向细胞（LPTC）空间池输入从本地基本运动检测器（EMD）相关的亮度变化从两个空间离散的输入信号延迟后，从一个。因此，LPTC速度最佳值取决于输入的空间分离和EMD的延迟特性。最近的研究表明，行为活动增加了LPTC速度最佳值，建模表明这起源于EMD的时间延迟滤波器。然而，行为诱导一个额外的后EMD效应：LPTC膜电导增加苍蝇。生理学调查活动导致突触前和突触后效应的程度，我们进行了Eristalis水平系统（HS）神经元的细胞内记录。我们在不同的时间频率适应前后构建对比反应函数，有和没有章鱼胺受体激动剂杀虫脒（CDM）。我们提取了三个运动适应组件，其中两个可能是突触前产生的LPTC，其中之一。我们发现，CDM影响早期，EMD相关的对比度增益降低，时间频率依赖性。然而，CDM引起的HS膜电导的变化消失期间和视觉刺激后。这表明，体力活动主要影响运动适应突触前的LPTC，而后EMD的影响很小。
Sensory systems adapt to prolonged stimulation by decreasing their response to continuous stimuli. Whereas visual motion adaptation has traditionally been studied in immobilized animals, recent work indicates that the animal's behavioral state influences the response properties of higher-order motion vision-sensitive neurons. During insect flight octopamine is released, and pharmacological octopaminergic activation can induce a fictive locomotor state. In the insect optic ganglia, lobula plate tangential cells (LPTCs) spatially pool input from local elementary motion detectors (EMDs) that correlate luminosity changes from two spatially discrete inputs after delaying the signal from one. The LPTC velocity optimum thereby depends on the spatial separation of the inputs and on the EMD's delay properties. Recently it was shown that behavioral activity increases the LPTC velocity optimum, with modeling suggesting this to originate in the EMD's temporal delay filters. However, behavior induces an additional post-EMD effect: the LPTC membrane conductance increases in flying flies. To physiologically investigate the degree to which activity causes presynaptic and postsynaptic effects, we conducted intracellular recordings of Eristalis horizontal system (HS) neurons. We constructed contrast response functions before and after adaptation at different temporal frequencies, with and without the octopamine receptor agonist chlordimeform (CDM). We extracted three motion adaptation components, where two are likely to be generated presynaptically of the LPTCs, and one within them. We found that CDM affected the early, EMD-associated contrast gain reduction, temporal frequency dependently. However, a CDM-induced change of the HS membrane conductance disappeared during and after visual stimulation. This suggests that physical activity mainly affects motion adaptation presynaptically of LPTCs, whereas post-EMD effects have a minimal effect.