As the oldest, but least understood sensory system in evolution, the olfactory system represents one of the most challenging research targets in sensory neurobiology. Although a large number of computational models of the olfactory system have been proposed, they do not account for the diversity in physiology, connectivity of local neurons, and several recent discoveries in the insect antennal lobe, a major olfactory organ in insects. Recent studies revealed that the response of some projection neurons were reduced by application of a GABA antagonist, and that insects are sensitive to odor pulse frequency. To account for these observations, we propose a spiking neural circuit model of the insect antennal lobe. Based on recent anatomical and physiological studies, we included three sub-types of local neurons as well as synaptic short-term depression (STD) in the model and showed that the interaction between STD and local neurons resulted in frequency-sensitive responses. We further discovered that the unexpected response of the projection neurons to the GABA antagonist is the result of complex interactions between STD and presynaptic inhibition, which is required for enhancing sensitivity to odor stimuli. Finally, we found that odor discrimination is improved if the innervation of the local neurons in the glomeruli follows a specific pattern. Our findings suggest that STD, presynaptic inhibition and diverse physiology and connectivity of local neurons are not independent properties, but they interact to play key roles in the function of antennal lobes.

中文翻译：

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短期抑郁，突触前抑制和局部神经元多样性在昆虫触角叶中起关键功能作用。

嗅觉系统是进化中最古老，但了解最少的感觉系统，是感觉神经生物学中最具挑战性的研究目标之一。尽管已经提出了嗅觉系统的大量计算模型，但是它们并没有考虑到生理学的多样性，局部神经元的连通性以及昆虫触角叶-昆虫的主要嗅觉器官-中的一些最新发现。最近的研究表明，使用GABA拮抗剂可降低某些投射神经元的反应，并且昆虫对气味脉冲频率敏感。为了解释这些发现，我们提出了昆虫触角波的尖峰神经回路模型。根据最近的解剖学和生理学研究，我们在模型中包括了三种亚型的局部神经元以及突触短期抑制（STD），并表明STD与局部神经元之间的相互作用导致了频率敏感反应。我们进一步发现，投射神经元对GABA拮抗剂的意外反应是STD与突触前抑制之间复杂相互作用的结果，这是增强对气味刺激的敏感性所必需的。最后，我们发现，如果肾小球中局部神经元的神经支配遵循特定的模式，则气味识别能力会得到改善。我们的研究结果表明，性病，突触前抑制和局部神经元的各种生理学和连通性不是独立的属性，但它们相互作用以在触角叶的功能中发挥关键作用。