Recurrent connections between higher olfactory brain areas and their role in mating state-dependent behaviour in Drosophila

内部状态强烈影响感官知觉，从而影响动物对周围世界的解释。在TP3项目中，我们关注的是内部状态、母性的一个非常重要的变化，以及它如何改变雌性嗅觉感知和行为的循环机制。雌性黑腹果蝇在交配后不久就会急剧改变行为，优先寻找营养丰富的产卵地点。为了找到这样的地方，雌性依靠嗅觉来探测关键的气味，包括多胺的腐烂气味。重要的是，她对多胺的偏好是通过交配来调节的，因此交配后约2周内，雌性会更喜欢高浓度的气味。我们之前已经证明，交配会在嗅觉处理的几个层面上引起变化。首先，交配诱导的肽能信号调节嗅觉感觉神经元中的多胺感知。其次，交配还通过调节特定的蘑菇体(MB)-支配多巴胺能神经元（DANs）来改变高级加工。最近，我们发现交配诱导的多胺感知的长期变化不仅需要MB来表达改变的偏好，而且令人惊讶的是，它也与交配相关的诱导有关。我们的最新数据表明，MB输出神经元（MBON）和DANs之间以及MBON和外侧角神经元（LH）之间的局部和远程循环连接对于诱导或表达更高的多胺偏好或两者都至关重要。在这里，我们将结合行为分析、基因操作和最新的体内功能成像与最近的连接组学数据来绘制和功能表征雌性动物生殖状态依赖的气味感知中这些循环回路基元。

Internal states strongly influence sensory perception and thereby an animal’s interpretation of the world around it. In project TP3, we focus on a highly important change in internal state, motherhood, and the recurrent circuit mechanisms of how it changes female olfactory perception and behaviour. Female Drosophila melanogaster drastically change behaviour shortly after mating and prioritize finding appropriate egglaying sites rich in nutrients. For finding such sites, females rely on the sense of smell to detect key odorants including the putrid odour of polyamines. Importantly, her preference for polyamines is modulated by mating such that a mated female will prefer higher concentrations of the odour for ~2 weeks after mating. We have previously shown that mating induces changes at several levels in olfactory processing. First, a mating-induced peptidergic signalling modulates polyamine sensing in olfactory sensory neurons. Second, mating also changes higher processing through modulation of specific mushroom body (MB)-innervating dopaminergic neurons (DANs). Most recently, we found that the long-lasting change in mating-induced polyamine perception requires the MB not only for the expression of a changed preference but, surprisingly, also for its mating-related induction. Our latest data suggest that local and long-range recurrent connections between MB output neurons (MBON) and DANs, and MBONs and neurons of the lateral horn (LH) are critical for either induction or expression of higher polyamine preference or both. Here, we will combine behavioural analysis, genetic manipulation, and state-of-the-art in vivo functional imaging with recent connectomics data to map and functionally characterize these recurrent circuit motifs in reproductive state-dependent odour perception in female animals.