Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany.
Department of Genetics, Faculty of Agriculture, Tanta University, 31111 Tanta, Egypt.
Learn Mem. 2024 Jun 11;31(5). doi: 10.1101/lm.053726.122. Print 2024 May.
larvae are an established model system for studying the mechanisms of innate and simple forms of learned behavior. They have about 10 times fewer neurons than adult flies, and it was the low total number of their neurons that allowed for an electron microscopic reconstruction of their brain at synaptic resolution. Regarding the mushroom body, a central brain structure for many forms of associative learning in insects, it turned out that more than half of the classes of synaptic connection had previously escaped attention. Understanding the function of these circuit motifs, subsequently confirmed in adult flies, is an important current research topic. In this context, we test larval for their cognitive abilities in three tasks that are characteristically more complex than those previously studied. Our data provide evidence for (i) conditioned inhibition, as has previously been reported for adult flies and honeybees. Unlike what is described for adult flies and honeybees, however, our data do not provide evidence for (ii) sensory preconditioning or (iii) second-order conditioning in larvae. We discuss the methodological features of our experiments as well as four specific aspects of the organization of the larval brain that may explain why these two forms of learning are observed in adult flies and honeybees, but not in larval .
幼虫是研究先天和简单形式的学习行为机制的成熟模型系统。它们的神经元数量比成年苍蝇少约 10 倍,正是由于它们的神经元总数较少,才能够以突触分辨率对其大脑进行电子显微镜重建。关于蘑菇体,这是昆虫中许多形式的联想学习的中央大脑结构,事实证明,以前有超过一半的突触连接类别被忽视了。理解这些随后在成年苍蝇中得到证实的电路基元的功能是当前一个重要的研究课题。在这方面,我们在三个任务中测试幼虫的认知能力,这些任务的特征比以前研究的任务更为复杂。我们的数据为(i)条件抑制提供了证据,这与以前在成年苍蝇和蜜蜂中报告的情况相同。然而,与在成年苍蝇和蜜蜂中描述的情况不同,我们的数据并没有为(ii)感觉前条件作用或(iii)幼虫的二阶条件作用提供证据。我们讨论了我们实验的方法学特征以及幼虫大脑组织的四个具体方面,这些方面可能解释了为什么这两种形式的学习在成年苍蝇和蜜蜂中观察到,而在幼虫中没有观察到。