Trimarchi J R, Schneiderman A M
Section of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853-2702.
J Comp Physiol A. 1995 Mar;176(3):355-64. doi: 10.1007/BF00219061.
We have monitored the patterns of activation of five muscles during flight initiation of Drosophila melanogaster: the tergotrochanteral muscle (a mesothoracic leg extensor), dorsal longitudinal muscles #3, #4 and #6 (wing depressors), and dorsal ventral muscle #Ic (a wing elevator). Stimulation of a pair of large descending interneurons, the giant fibers, activates these muscles in a stereotypic pattern and is thought to evoke escape flight initiation. To investigate the role of the giant fibers in coordinating flight initiation, we have compared the patterns of muscle activation evoked by giant fiber stimulation with those during flight initiations executed voluntarily and evoked by visual and olfactory stimuli. Visually elicited flight initiations exhibit patterns of muscle activation indistinguishable from those evoked by giant fiber stimulation. Olfactory-induced flight initiations exhibit patterns of muscle activation similar to those during voluntary flight initiations. Yet only some benzaldehyde-induced and voluntary flight initiations exhibit patterns of muscle activation similar to those evoked by giant fiber stimulation. These results indicate that visually elicited flight initiations are coordinated by the giant fiber circuit. By contrast, the giant fiber circuit alone cannot account for the patterns of muscle activation observed during the majority of olfactory-induced and voluntary flight initiations.
背板转子肌（中胸腿部伸肌）、背纵肌#3、#4和#6（翅膀下压肌）以及背腹肌#Ic（翅膀上举肌）。刺激一对大型下行中间神经元——巨纤维，会以刻板模式激活这些肌肉，并且被认为能引发逃避飞行起始。为了研究巨纤维在协调飞行起始中的作用，我们将巨纤维刺激诱发的肌肉激活模式与视觉和嗅觉刺激诱发的自主飞行起始过程中的肌肉激活模式进行了比较。视觉诱发的飞行起始所呈现的肌肉激活模式与巨纤维刺激诱发的模式无法区分。嗅觉诱发的飞行起始所呈现的肌肉激活模式与自主飞行起始过程中的模式相似。然而，只有一些苯甲醛诱发的和自主的飞行起始呈现出与巨纤维刺激诱发的模式相似的肌肉激活模式。这些结果表明，视觉诱发的飞行起始由巨纤维回路协调。相比之下，仅巨纤维回路无法解释大多数嗅觉诱发的和自主飞行起始过程中观察到的肌肉激活模式。
