Functional assignment of glomeruli and projection interneurons of antennal lobe in insect brain

我们已经确定了水温感受器神经元和机械感受器神经元终止的区域。水热感受器神经元被来自感受器的钴离子染色，其中一个感受器含有两个湿感受器，一个冷感受器和第四个细胞，另一个含有一个冷感受器和少数嗅觉感受器细胞。感水感受器和感温感受器中的神经元和感温感受器和嗅觉感受器中的神经元终止于位于背叶附近的肾小球丛中。水温感受性感受器中的另外两个神经元也终止于同一区域的另一簇肾小球。这些簇中的每一个似乎都形成了一个类似于雄蛾的大肾小球复合体的肾小球复合体。另一方面，对水或热刺激反应强烈的投射神经元在这些肾小球簇内有树突分支，但对这些刺激反应较弱的投射神经元似乎终止于其他肾小球。因此，湿度和温度信息似乎主要通过这些肾小球簇传递到特定的投射中间神经元。机械感受器上的机械感受器神经元也用同样的方法染色。神经元穿过背叶和三脑，终止于食道下神经节。这一通路与感水感受器和感温感受器的第四个神经元的通路非常相似。

We have identified the regions where the hygro- and thermoreceptor neurons and mechanoreceptor neurons terminated. For the hygro- and thermoreceptor neurons the neurons were ionophoritically stained by cobalt from the sensilla, one of which contained two hygroreceptors, one cold receptor and the fourth cell and the other contained one cold receptor and a few olfactory receptor cells. A neuron in the hygro- and thermoreceptive sensillum and a neuron in the thermoreceptive and olfactory sensillum terminate in a cluster of glomeruli which located near a dorsal lobe. Two other neurons in the hygro- and thermoreceptive sensilla also terminated in another cluster of glomeruli in the same region. Each of these clusters appears to form a complex of glomeruli similar to the macroglomerular complex of male moths. On the other hand, the projection neurons that respond strongly to hygro- or thermal stimulations have dendritic arborizations in these glomerular clusters but the projection neurons show weak responses to these stimulations appear to terminate in other glomeruli. Therefore, humidity and temperature information appears to be primarily transmitted to the particular projection interneurons through these glomerular clusters, respectively. The mechanoreceptor neurons were also stained in the same method from mechanoreceptive sensilla. The neurons passed through the dorsal lobe and the tritocerebrum and terminated in suboesophageal ganglion. This pass way was very similar to that of the fourth neuron in the hygro- and thermoreceptive sensilla.