Homberg U, Montague R A, Hildebrand J G
Arizona Research Laboratories, University of Arizona, Tucson 85721.
Cell Tissue Res. 1988 Nov;254(2):255-81. doi: 10.1007/BF00225800.
In the moth Manduca sexta, the number and morphology of neuronal connections between the antennal lobes and the protocerebrum were examined. Cobalt injections revealed eight morphological types of neurons with somata adjacent to the AL neuropil that project in the inner, middle, and outer antenno-cerebral tracts to the proto-cerebrum. Neurons innervating the macroglomerular complex and many neurons with fibers in the inner antenno-cerebral tract have uniglomerular antennal-lobe arborizations. Most neurons in the middle and outer antenno-cerebral tracts, on the other hand, seem to innervate more than one glomerulus. Protocerebral areas receiving direct input from the antennal lobe include the calyces of the mushroom bodies, and circumscribed areas termed "olfactory foci" in the lateral horn of the protocerebrum and several other regions, especially areas in close proximity to the mushroom bodies. Fibers in the inner antenno-cerebral tract that innervate the male-specific macroglomerular complex have arborizations in the protocerebrum that are distinct from the projections of sexually non-specific neurons. Protocerebral neurons projecting into the antennal lobe are much less numerous than antennal-lobe output cells. Most of these protocerebral fibers enter the antennal lobe in small fiber tracts that are different from those described above. In the protocerebrum, these centrifugal cells arborize in olfactory foci and also in the inferior median protocerebrum and the lateral accessory lobes. The morphological diversity of connections between the antennal lobes and the protocerebrum, described here for the first time on a single-cell level, suggests a much greater physiological complexity of the olfactory system than has been assumed so far.
在烟草天蛾中，研究了触角叶与原脑之间神经元连接的数量和形态。钴注射显示，有八种形态类型的神经元，其胞体毗邻触角叶神经纤维网，通过内、中、外触角脑束投射到原脑。支配大glomerular复合体的神经元以及许多在内触角脑束中有纤维的神经元具有单glomerular触角叶分支。另一方面，中、外触角脑束中的大多数神经元似乎支配不止一个glomerulus。接受来自触角叶直接输入的原脑区域包括蘑菇体的萼片，以及原脑侧角中称为“嗅觉焦点”的限定区域和其他几个区域，特别是靠近蘑菇体的区域。支配雄性特异性大glomerular复合体的内触角脑束中的纤维在原脑中的分支与性非特异性神经元的投射不同。投射到触角叶的原脑神经元比触角叶输出细胞少得多。这些原脑纤维大多通过与上述不同的小纤维束进入触角叶。在原脑中，这些离心细胞在嗅觉焦点以及中脑下部和外侧副叶中分支。本文首次在单细胞水平上描述的触角叶与原脑之间连接的形态多样性表明，嗅觉系统的生理复杂性比迄今为止所设想的要大得多。
