Figure 1: The consistent Drosophila larval NMJ. (a) Dissection of third instar Drosophila larvae reveals a distinct body plan, which is consistent between all larvae, comprised of 14 segments, 3 of which define the head and mouth region, 3 thoracic segments (T1–T3), and 8 abdominal segments (A1–A8; segment A3 indicated by the white dotted line). The CNS is outlined in magenta, the main nerve trunks indicated by magenta arrows. The trachea, which supply oxygen to the nerves and muscles remain intact, and two are indicated by the light cyan arrow. (b) Abdominal segments A2–A7 are composed of 2 bilaterally symmetrical hemisegments, each of which displays an archetypal structure comprising 30 distinct muscles. (c) These hemisegments have been extensively studied with a number of specific NMJs utilised as model synapses for a range of experimental purposes. Here we show muscle 6/7 (hemisegment A3). This muscle pairing has been extensively used for electrophysiological experiments due to the large size and accessibility of the NMJ, with the presynaptic motor neuron clearly visible innervating muscles 6 and 7. In this diagram we demonstrate how a suction electrode can be used to stimulate a single segmental nerve whilst recordings are made from muscle 6 (the larger of the pair).