Gil Mariana, Menzel Randolf, De Marco Rodrigo J
Department of Biology, Chemistry, and Pharmacy, Institute of Biology and Neurobiology, Free University of Berlin, Berlin, Germany.
Learn Mem. 2009 Jun 24;16(7):426-32. doi: 10.1101/lm.1419109. Print 2009 Jul.
We report a hitherto unknown form of side-specific learning in honeybees. We trained bees individually by coupling gustatory and mechanical stimulation of each antenna with either increasing or decreasing volumes of sucrose solution offered to the animal's proboscis along successive learning trials. Next, we examined their proboscis extension response (PER) after stimulation of each antenna 1, 2, 3, and 24 h after training. The bees extended their proboscises earlier after stimulation of the antenna that had been coupled with increasing volumes than after stimulation of the antenna that had been coupled with decreasing volumes, thereby revealing short- and long-term side differences in the bees' PE reaction time. The bees' reaction time correlated well with the reaction time of the muscles M17. Long-term side differences in reaction time were prevented by repetitive antennal stimulation. Mechanosensory input was indispensable and sufficient for revealing side differences in reaction time. Such differences were specific to the gustatory input that the bees experienced during training. Our results show that side differences in the bees' PE reaction time depend upon the activation of side-specific reward memories. These memories are formed via the combined effect of a specific property of reward, i.e., that its magnitude increases or decreases over time, and side information seemingly relying on mechanosensory input. We present a learning procedure suitable to study reward learning in honeybees, which includes precise behavioral measures, physiological correlates of behavior, and within-animal controls. This procedure will prove fruitful in pharmacological and electrophysiological analyses of the neural substrates underlying reward memories in honeybees.
我们报告了蜜蜂中一种迄今未知的特定侧别学习形式。我们通过将每根触角的味觉和机械刺激与在连续学习试验中提供给动物喙的蔗糖溶液体积的增加或减少相耦合，对蜜蜂进行个体训练。接下来，我们在训练后1小时、2小时、3小时和24小时刺激每根触角后，检查它们的喙伸展反应（PER）。与接受递减体积蔗糖溶液耦合刺激的触角相比，接受递增体积蔗糖溶液耦合刺激的触角在受到刺激后，蜜蜂更早地伸出它们的喙，从而揭示了蜜蜂喙伸展反应时间在短期和长期的侧别差异。蜜蜂的反应时间与M17肌肉的反应时间密切相关。重复的触角刺激可防止反应时间的长期侧别差异。机械感觉输入对于揭示反应时间的侧别差异是必不可少且足够的。这种差异特定于蜜蜂在训练期间所经历的味觉输入。我们的结果表明，蜜蜂喙伸展反应时间的侧别差异取决于特定侧别奖励记忆的激活。这些记忆是通过奖励的一种特定属性（即其大小随时间增加或减少）与看似依赖机械感觉输入的侧别信息的联合作用形成的。我们提出了一种适用于研究蜜蜂奖励学习的学习程序，该程序包括精确的行为测量、行为与生理的相关性以及动物体内对照。这一程序在对蜜蜂奖励记忆背后的神经基质进行药理学和电生理学分析中将被证明是富有成效的。
