Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany,
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2013 Nov;199(11):981-96. doi: 10.1007/s00359-013-0821-y. Epub 2013 Apr 23.
Animals face highly complex and dynamic olfactory stimuli in their natural environments, which require fast and reliable olfactory processing. Parallel processing is a common principle of sensory systems supporting this task, for example in visual and auditory systems, but its role in olfaction remained unclear. Studies in the honeybee focused on a dual olfactory pathway. Two sets of projection neurons connect glomeruli in two antennal-lobe hemilobes via lateral and medial tracts in opposite sequence with the mushroom bodies and lateral horn. Comparative studies suggest that this dual-tract circuit represents a unique adaptation in Hymenoptera. Imaging studies indicate that glomeruli in both hemilobes receive redundant sensory input. Recent simultaneous multi-unit recordings from projection neurons of both tracts revealed widely overlapping response profiles strongly indicating parallel olfactory processing. Whereas lateral-tract neurons respond fast with broad (generalistic) profiles, medial-tract neurons are odorant specific and respond slower. In analogy to "what-" and "where" subsystems in visual pathways, this suggests two parallel olfactory subsystems providing "what-" (quality) and "when" (temporal) information. Temporal response properties may support across-tract coincidence coding in higher centers. Parallel olfactory processing likely enhances perception of complex odorant mixtures to decode the diverse and dynamic olfactory world of a social insect.
动物在其自然环境中面临着高度复杂和动态的嗅觉刺激，这需要快速而可靠的嗅觉处理。并行处理是支持这一任务的感觉系统的共同原则，例如在视觉和听觉系统中，但它在嗅觉中的作用仍不清楚。在蜜蜂中的研究集中在双嗅觉途径上。两组投射神经元通过外侧和内侧轨道以相反的顺序连接两个触角叶半脑的神经节，与蘑菇体和侧角相连。比较研究表明，这种双轨电路代表了膜翅目昆虫的独特适应。成像研究表明，两个半脑的神经节都接收冗余的感觉输入。最近来自两条轨道的投射神经元的同时多单位记录显示，广泛重叠的反应谱强烈表明存在并行嗅觉处理。虽然外侧轨道神经元反应迅速，具有广泛（一般性）的图谱，但内侧轨道神经元对气味具有特异性，反应较慢。与视觉通路中的“什么”和“哪里”子系统类似，这表明两个平行的嗅觉子系统提供“什么”（质量）和“何时”（时间）信息。时间响应特性可能支持在更高的中心进行跨轨道的吻合编码。并行嗅觉处理可能增强对复杂气味混合物的感知，以解码社会性昆虫多样化和动态的嗅觉世界。
