Structural plasticity of synaptic circuits in the honeybee brain mushroom bodies associated with behavioral learning

对行为学习背后的细胞机制的研究提供了越来越多的证据，表明新行为的习得诱导突触发生和现有突触的重组。到目前为止，这个问题主要是针对哺乳动物的大脑进行的研究，而其他表现出复杂行为形式的高度组织化的动物群体则没有在这方面进行研究。这项工作的目的是通过定量电子显微镜（EM）来发现经验相关的突触发生是否发生在蜜蜂蘑菇体（mb）中，这是参与嗅觉记忆形成的高级大脑中心。更具体地说，我们将关注蘑菇体输入部位抑制性局部突触回路的经验相关可塑性。这将通过在MB抑制回路内操作的GABA¿神经递质染色的LM-和EM制剂上的突触量化来评估。我们要解决的另一个问题是，单次或多次学习试验是否与MBs的结构可塑性有关。假设动态肌动蛋白介导突触或突触回路的可能重组，我们将使用嗅觉调节实验范式来估计蘑菇体在学习过程中丝状肌动蛋白的动态。

Investigation of cellular mechanisms underlying behavioral learning provides a growing body of evidence that acquisition of new behaviors induces synaptogenesis and restructuring of existing synapses. So far this question is mostly addressed to work carried out on the mammalian brain, while other highly organized animal groups exhibiting complex forms of behavior are not studied in this respect. The aim of the proposed work is to find out by means of quantitative electron microscopy (EM) whether experience-associated synaptogenesis occurs in the honeybee mushroom bodies (MBs), the higher brain centers involved in the formation of olfactory memory. More specifically, we shall focus on experience-related plasticity of inhibitory local synaptic circuits within the mushroom body input sites. This will be assessed by quantification of synapses on LM- and EM preparations stained for GABA ¿ neurotransmitters operating within the MB inhibitory circuits. The other question that we shall address is whether single or multiple learning trials are associated with structural plasticity in the MBs. Assuming that dynamic actin mediates possible restructuring of synapses or synaptic circuits, we will use the olfactory conditioning experimental paradigm to estimate filamentous actin dynamics within mushroom bodies during the learning process.