Department of Stem Cell Biology, Institute of Embryology and Genetics, Kumamoto University, Kumamoto, Japan.
PLoS One. 2012;7(2):e32007. doi: 10.1371/journal.pone.0032007. Epub 2012 Feb 16.
We analyzed the effects of dopamine signaling on the temporal organization of rest and activity in Drosophila melanogaster. Locomotor behaviors were recorded using a video-monitoring system, and the amounts of movements were quantified by using an image processing program. We, first, confirmed that rest bout durations followed long-tailed (i.e., power-law) distributions, whereas activity bout durations did not with a strict method described by Clauset et al. We also studied the effects of circadian rhythm and ambient temperature on rest bouts and activity bouts. The fraction of activity significantly increased during subjective day and at high temperature, but the power-law exponent of the rest bout distribution was not affected. The reduction in rest was realized by reduction in long rest bouts. The distribution of activity bouts did not change drastically under the above mentioned conditions. We then assessed the effects of dopamine. The distribution of rest bouts became less long-tailed and the time spent in activity significantly increased after the augmentation of dopamine signaling. Administration of a dopamine biosynthesis inhibitor yielded the opposite effects. However, the distribution of activity bouts did not contribute to the changes. These results suggest that the modulation of locomotor behavior by dopamine is predominantly controlled by changing the duration of rest bouts, rather than the duration of activity bouts.
我们分析了多巴胺信号对黑腹果蝇休息和活动的时间组织的影响。使用视频监测系统记录运动行为，并使用图像处理程序对运动幅度进行量化。我们首先通过 Clauset 等人描述的严格方法证实，休息阶段的持续时间遵循长尾（即幂律）分布，而活动阶段的持续时间没有遵循。我们还研究了昼夜节律和环境温度对休息和活动阶段的影响。在主观白天和高温下，活动的比例显著增加，但休息阶段分布的幂律指数不受影响。休息时间的减少是通过减少长休息时间实现的。在上述条件下，活动阶段的分布没有发生剧烈变化。然后我们评估了多巴胺的影响。多巴胺信号增强后，休息阶段的分布变得不那么长尾，活动时间显著增加。多巴胺生物合成抑制剂的给药产生了相反的效果。然而，活动阶段的分布对这些变化没有贡献。这些结果表明，多巴胺对运动行为的调节主要是通过改变休息阶段的持续时间来控制的，而不是活动阶段的持续时间。
