Taste representations in the Drosophila brain

描述(申请人提供)：这项建议的长期目标是增加对味觉识别和味觉的理解。拟议的实验将在果蝇--黑腹果蝇身上进行，这是一种具有简单的味觉系统和强大的味觉行为的有机体，可以通过分子、遗传和电生理方法进行。果蝇的味觉识别是由鼻子、内部口器、腿、翅膀和产卵器上的感觉神经元介导的。初步研究已经确定了一个由56个候选味觉受体基因(GR)组成的大家族的特征，并揭示了每个味觉神经元表达一个或几个受体。 这些不同的味觉神经元在大脑中是如何表现的？在躯体感觉和视觉系统中，感觉投射是根据神经元在外围的位置来分离的，以提供大脑中刺激位置的地形图。在嗅觉系统中，根据神经元表达的气味感受器来分离投射，这样就可以映射出气味的质量，而不是它的外围位置。拟议中的实验旨在确定大脑中味觉的分子和位置表征。建议的目标如下： (1)确定味觉投射是否根据它们所表达的受体而分离； (2)根据它们在外围的位置来确定它们是否被隔离； (3)味觉图与机械感觉图的比较； (4)确定味觉神经元的突触联系。 拟议中的实验将提供对大脑中味觉表征逻辑的洞察，最终目的是了解感觉知觉是如何在神经回路中编码的。

DESCRIPTION (provided by applicant): The long-term objectives of this proposal are to increase understanding of taste recognition and taste perception. The proposed experiments will be conducted in the fruit fly, Drosophila melanogaster, an organism with a simple gustatory system and robust gustatory behaviors that is amenable to molecular, genetic and electrophysiological approaches. Taste recognition in Drosophila is mediated by sensory neurons on the proboscis, internal mouthparts, legs, wings, and ovipositor. Preliminary studies have characterized a large family of 56 candidate gustatory receptor genes (GRs) and revealed that each gustatory neuron expresses one or a few receptors. How are these different gustatory neurons represented in the brain? In the somatosensory and visual systems, sensory projections are segregated according to the location of the neuron in the periphery to provide a topographic map of stimulus position in the brain. In the olfactory system, projections are segregated according to the odorant receptor that the neuron expresses, such that the quality of an odor is mapped rather than its peripheral position. The proposed experiments are designed to determine the molecular and positional representations of tastes in the brain. The following aims are proposed: (1) to determine if gustatory projections are segregated according to the receptor they express; (2) to determine if they are segregated according to their location in the periphery; (3) to compare gustatory maps with mechanosensory maps; (4) to identify synaptic connections of gustatory neurons. The proposed experiments will provide insight into the logic of taste representations in the brain, with the ultimate aim of understanding how sensory perception is encoded in neural circuits.