Physiological properties and response modulations of mushroom body feedback neurons during olfactory learning in the honeybee, Apis mellifera
Physiological properties and response modulations of mushroom body feedback neurons during olfactory learning in the honeybee, Apis mellifera
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DOI：
10.1007/s003590050417
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发表时间：
1999-12-01
影响因子：
2.1
通讯作者：
Grünewald, B
中科院分区：
文献类型：
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作者：
Grünewald, B
蘑菇体是昆虫大脑的中枢结构，与昆虫的嗅觉学习密切相关。在蘑菇体内，γ-氨基丁酸（GABA）免疫反应反馈神经元是最突出的神经元群。通过分析在体嗅觉学习过程中反馈神经元对气味反应的调制，研究了蘑菇体内抑制性神经活动的可塑性。在蜜蜂，蜜蜂，反馈神经元细胞内记录在他们的神经突。他们在没有实验刺激的情况下产生了复杂的动作电位模式。突触后电位的总和表明它们的突触输入区域位于叶内。气味和触角蔗糖刺激诱发兴奋性相位紧张性反应。单个神经元对不同的气味有反应，不同神经元对同一种气味的反应差异很大。通过比较一次试验嗅觉条件反射或敏化前后反馈神经元的气味反应来确定反应调制。配对后不久，气味刺激与蔗糖奖励，气味诱导的尖峰活动的反馈神经元减少。重复的气味刺激单独，等距的条件反射实验中，并没有影响气味诱导的兴奋。单一的致敏试验也没有改变气味反应。这些研究结果表明，蘑菇体内的气味诱导的抑制水平是由经验特别调制的。
Mushroom bodies are central brain structures and essentially involved in insect olfactory learning. Within the mushroom bodies gamma-aminobutyric acid (GABA)-immunoreactive feedback neurons are the most prominent neuron group. The plasticity of inhibitory neural activity within the mushroom body was investigated by analyzing modulations of odor responses of feedback neurons during olfactory learning in vivo. In the honeybee, Apis mellifera, feedback neurons were intracellularly recorded at their neurites. They produced complex patterns of action potentials without experimental stimulation. Summating postsynaptic potentials indicate that their synaptic input region lies within the lobes. Odor and antennal sucrose stimuli evoked excitatory phasic-tonic responses. Individual neurons responded to various odors, responses of different neurons to the same odor were highly variable. Response modulations were determined by comparing odor responses of feedback neurons before and after one-trial olfactory conditioning or sensitisation. Shortly after pairing an odor stimulus with a sucrose reward, odor-induced spike activity of feedback neurons decreased. Repeated odor stimulations alone, equally spaced as in the conditioning experiment, did not affect the odor-induced excitation. A single sensitisation trial also did not alter odor responses. These findings indicate that the level of odor-induced inhibition within the mushroom bodies is specifically modulated by experience.