Ian Elena, Kirkerud Nicholas H, Galizia C Giovanni, Berg Bente G
Norwegian University of Science and Technology (NTNU), Department of Psychology, Trondheim, Norway.
Universität Konstanz Fachbereich Biologie, Konstanz, Germany.
PLoS One. 2017 May 3;12(5):e0175513. doi: 10.1371/journal.pone.0175513. eCollection 2017.
Male moths possess a highly specialized olfactory system comprised of two segregated sub-arrangements dedicated to processing information about plant odors and pheromones, respectively. Communication between these two sub-systems has been described at the peripheral level, but relatively little is known about putative interactions at subsequent synaptic relays. The male moth faces the challenge of seeking out the conspecific female in a highly dynamic odor world. The female-produced pheromone blend, which is a limited resource serving as guidance for the male, will reach his antennae in intermittent pockets of odor filaments mixed with volatiles from various plants. In the present study we performed calcium imaging for measuring odor-evoked responses in the uni-glomerular antennal-lobe projection neurons (analog to mitral cells in the vertebrate olfactory bulb) of Helicoverpa armigera. In order to investigate putative interactions between the two sub-systems tuned to plant volatiles and pheromones, respectively, we performed repeated stimulations with a selection of biologically relevant odors. We found that paired stimulation with a plant odor and the pheromone led to suppressed responses in both sub-systems as compared to those evoked during initial stimulation including application of each odor stimulus alone. The fact that the suppression persisted also after pairing, indicates the existence of a Hebbian-like plasticity in the primary olfactory center established by temporal pairing of the two odor stimulation categories.
雄蛾拥有高度专业化的嗅觉系统，该系统由两个独立的子系统组成，分别专门用于处理有关植物气味和信息素的信息。这两个子系统之间的交流已在周边水平上有所描述，但对于后续突触中继处可能存在的相互作用却知之甚少。雄蛾面临着在高度动态的气味环境中寻找同种雌蛾的挑战。雌蛾产生的信息素混合物是一种有限的资源，为雄蛾提供指引，它会在与各种植物挥发物混合的气味细丝间歇囊中到达雄蛾的触角。在本研究中，我们进行了钙成像，以测量棉铃虫单肾小球触角叶投射神经元（类似于脊椎动物嗅球中的 mitral 细胞）中气味诱发的反应。为了分别研究两个分别针对植物挥发物和信息素的子系统之间可能存在的相互作用，我们用一系列具有生物学相关性的气味进行了重复刺激。我们发现，与包括单独施加每种气味刺激在内的初始刺激期间诱发的反应相比，用植物气味和信息素进行配对刺激会导致两个子系统中的反应均受到抑制。配对后抑制仍然持续这一事实表明，通过两种气味刺激类别的时间配对在初级嗅觉中枢中存在类似赫布可塑性的现象。
