a, Schematic and representative image depicting direct stimulation of vAB3 neurons by iontophoresis of neurotransmitter onto their dendrites within the VNC. Maximum intensity z-projection (top) and single z-plane (bottom) showing electrode placement in the VNC. The electrode is filled with neurotransmitter and Texas-red dye (red) to enable precise targeting in the Fru+ neuropil (green). b, Representative multi-plane fluorescence increase of Fru+ brain neurons in D.