part of continuous with synaptic neuropil subdomain subregion AA of AMMC zone A subregion AD of AMMC zone A antennal mechanosensory and motor center subarea AD fly_anatomy.ontology JON bundle AD Johnston organ neuron bundle AD primary auditory center subarea AD FBbt:00047899 JON-AD VFB:FBbt_00047899 bundle A dorsal FlyBrain_NDB:10187 Subregion of AMMC zone A. This contains the dorsal subbundle of Johnston organ neuron axons that forms from bundle AA (subregion AA) and enters the ventrolateral protocerebrum. It is rich with the presynapses of Johnston organ neurons. antennal mechanosensory and motor center zone A