fasciculates with sends synaptic output to cell muscle cell of proboscis muscle 4 adult labial nerve adult labial motor neuron proboscis muscle 4 motor neuron 2021-03-29T15:57:39Z Motor neuron that innervates proboscis muscle 4, which extends the haustellum (McKellar et al., 2020). Its soma is found in a ventral part of the cell body rind of the subesophageal zone (McKellar et al., 2020). It arborizes in the ventral subesophageal zone and travels to the proboscis via the labial nerve (McKellar et al., 2020). FBbt:00051186 proboscis motor neuron mn4 VFB:FBbt_00051186 fly_anatomy.ontology rostrum muscle motor neuron