Hige Toshihide
Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA.
Neurosci Res. 2018 Apr;129:8-16. doi: 10.1016/j.neures.2017.05.002. Epub 2017 May 5.
Nervous systems have evolved to translate external stimuli into appropriate behavioral responses. In an ever-changing environment, flexible adjustment of behavioral choice by experience-dependent learning is essential for the animal's survival. Associative learning is a simple form of learning that is widely observed from worms to humans. To understand the whole process of learning, we need to know how sensory information is represented and transformed in the brain, how it is changed by experience, and how the changes are reflected on motor output. To tackle these questions, studying numerically simple invertebrate nervous systems has a great advantage. In this review, I will feature the Pavlovian olfactory learning in the fruit fly, Drosophila melanogaster. The mushroom body is a key brain area for the olfactory learning in this organism. Recently, comprehensive anatomical information and the genetic tool sets were made available for the mushroom body circuit. This greatly accelerated the physiological understanding of the learning process. One of the key findings was dopamine-induced long-term synaptic plasticity that can alter the representations of stimulus valence. I will mostly focus on the new studies within these few years and discuss what we can possibly learn about the vertebrate systems from this model organism.
神经系统已经进化到能够将外部刺激转化为适当的行为反应。在不断变化的环境中，通过依赖经验的学习来灵活调整行为选择对于动物的生存至关重要。联想学习是一种简单的学习形式，从蠕虫到人类都广泛存在。为了理解学习的全过程，我们需要知道感觉信息在大脑中是如何被表征和转换的，它是如何因经验而改变的，以及这些变化是如何反映在运动输出上的。为了解决这些问题，研究数量上简单的无脊椎动物神经系统具有很大优势。在这篇综述中，我将重点介绍果蝇（Drosophila melanogaster）的巴甫洛夫式嗅觉学习。蘑菇体是这种生物体嗅觉学习的关键脑区。最近，关于蘑菇体回路的全面解剖学信息和基因工具集已经具备。这极大地加速了对学习过程的生理学理解。其中一个关键发现是多巴胺诱导的长期突触可塑性，它可以改变刺激效价的表征。我将主要关注这几年内的新研究，并讨论我们从这个模式生物中可能学到的关于脊椎动物系统的知识。
