Confocal image of the Drosophila neuromuscular junction depicting two motor neuron subtypes co-innervating a common muscle target, where the blue color presents the neuronal membrane (labeled by anti-HRP) and synaptic vesicles are labeled in magenta (anti-vesicular glutamate transporter). The larger boutons (circular areas in green, labeled with anti-Discs Large), represent the “tonic” motor neuron Ib terminals, while the smaller boutons correspond to the “phasic-like” motor neuron Is terminals. In this issue, He et al. characterize structural and functional signatures of tonic vs phasic glutamatergic synapses. For more information, see the article by He et al. (pages 4598–4611). Cover image: Yifu Han and Kaikai He.