蘑菇体—昆虫嗅觉学习和记忆中心

Mushroom Body—Center of Insect Olfactory Learning and Memory

蘑菇体(蕈形体)是昆虫脑内非常重要的一个结构,构成蘑菇体的冠和叶在不同目昆虫中高度分化,其结构虽然保守,但形态上的变化在一定程度上反映了昆虫的进化地位.冠是触角叶嗅觉投射神经元的主要投射区,叶通过输出神经元联系蘑菇体与其它脑区.冠和叶在嗅觉记忆中不可或缺,垂直叶(α叶)支持长时记忆,中叶(γ叶)支持短时记忆.蘑菇体对嗅觉记忆的形成尤其是记忆的再现(提取)具有重要作用.乙酰胆碱(Ach)、γ-氨基丁酸(GABA)和一氧化氮(NO)等是蘑菇体嗅觉突触传递的主要神经递质.蘑菇体内的第二信使系统cAMP-PKA途径和NO-cGMP途径在嗅觉学习和记忆中起基础性作用.

Mushroom body （MB） is one of the important structures in insect brain. Although MB is conserved, the structure, calyx and lobes of MB are highly differentiated among the different order of insects. Morphological differenees of MB embody insect evolution status to the extent. Calyx is one of the main regions that MB receives input from antenna olfaetory projection neurons, whereas lobes link MB to other brain regions through efferent extrinsic neurons. Both calyx and lobes are indispensable for olfactory learning and memory. Different subsets of lobes play different functional roles. Vertical lobe （alpha lobe） supports long-term memory, while median lobe （gamma lobe） supports short-term memory. MB is required for olfaetory memory formation, especially for memory retrieval. The aeetylcholine （Aeh）, γ-aminobutyrie acid （GABA） and nitric oxide （NO） are major neurotransmitters for olfaetion synaptic transmission in MB. The second messenger systems eAMP-PKA pathway and NO-cGMP pathway whieh exist in MB play an essential role for insect learning and memory.