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. 2008 Dec 23;18(24):1955–1960. doi: 10.1016/j.cub.2008.10.067

Figure 1.

Figure 1

Neurons and Muscles of the Drosophila Giant Fiber System

The Giant Fiber System mediates escape behavior in the fly. Visual stimuli activate a pair of large interneurons, the Giant Fibers (GF, red). In the brain, the GFs form synaptic connections with the giant commissural interneurons (GCI, orange). The GF axons descend to the mesothoracic ganglion, where they terminate in characteristic lateral bends. The GF bends form extensive synaptic connections with the medially directed dendrites of the motorneurons (TTMn, blue) of the tergotrochanteral (jump) muscles (TTM, brown; left) of the middle leg. Just before the bends, the GF axons synapse with the peripherally synapsing interneurons (PSI, green), which, in turn, innervate the motorneurons (DLMn, yellow) of the dorsal longitudinal (flight) muscles (DLM, pink; right). The PSI axons and terminal tips of the TTMn medial dendrites synapse with one another at the midline. The central synapses are electrical or mixed electrochemical synapses. The neuromuscular junctions, which, for clarity, are shown on one side only of the bilaterally symmetrically pathway, are chemical synapses. Reprinted from [13] with permission from Elsevier.