Global electrosensory oscillations enhance directional responses of midbrain neurons in Eigenmannia
Global electrosensory oscillations enhance directional responses of midbrain neurons in Eigenmannia
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DOI：
10.1152/jn.00311.2006
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发表时间：
2006-11-01
影响因子：
2.5
通讯作者：
Fortune, E. S.
中科院分区：
文献类型：
--
作者：
Ramcharitar, J. U.;Tan, E. W.;Fortune, E. S.
Eigenmannia是一种弱电鱼类，它表现出一种特殊的行为，称为干扰回避反应（jamming avoidance response，缩写为EJAR）。这导致了同类群体中的Eigenmannia和单独的Eigenmannia之间的分类差异。群体中的鱼表现出持续的行为，从而经历持续的，全球同步的20至50赫兹的电感觉振荡，而孤独的鱼没有。虽然先前的研究已经表明，这些持续的信号不会显著降低电感觉行为，但这些振荡仍然会引起中脑回路中的短期突触抑制。由于短期突触抑制可以有深远的影响，通过突触的信息传输，我们研究了在清醒的中脑神经元的细胞内记录的反应的差异，行为的鱼移动电感觉图像的条件下，模仿孤独的鱼和鱼的群体。在孤独的条件下，移动的物体引起高斯或正弦突触后电位（PSP），通常表现出优先反应的运动方向。令人惊讶的是，当在存在全局振荡的情况下呈现相同的刺激时，在所有测试的神经元中方向选择性增加。PSP幅度的差异幅度的首选和非首选方向与短期突触抑制的措施在这两种情况下。电感觉的后果，似乎导致在中脑神经元的运动方向的代表性增强。这些数据也支持短期突触抑制在方向反应的产生和调制中的作用。
Eigenmannia, a genus of weakly electric fish, exhibits a specialized behavior known as the jamming avoidance response ( JAR). The JAR results in a categorical difference between Eigenmannia that are in groups of conspecifics and those that are alone. Fish in groups exhibit the JAR behavior and thereby experience ongoing, global synchronous 20- to 50-Hz electrosensory oscillations, whereas solitary fish do not. Although previous work has shown that these ongoing signals do not significantly degrade electrosensory behavior, these oscillations nevertheless elicit short-term synaptic depression in midbrain circuits. Because short-term synaptic depression can have profound effects on the transmission of information through synapses, we examined the differences in intracellularly recorded responses of midbrain neurons in awake, behaving fish to moving electrosensory images under electrosensory conditions that mimic solitary fish and fish in groups. In solitary conditions, moving objects elicited Gaussian or sinusoidal postsynaptic potentials (PSPs) that commonly exhibited preferential responses to a direction of motion. Surprisingly, when the same stimulus was presented in the presence of the global oscillations, directional selectivity was increased in all neurons tested. The magnitudes of the differences in PSP amplitude for preferred and nonpreferred directions were correlated with a measure of short-term synaptic depression in both conditions. The electrosensory consequences of the JAR appear to result in an enhancement of the representation of direction of motion in midbrain neurons. The data also support a role for short-term synaptic depression in the generation and modulation of directional responses.