Synapsin is an evolutionarily conserved presynaptic phosphoprotein. It is encoded by only one gene in the "Drosophila" genome and is expressed throughout the nervous system. It regulates the balance between reserve and releasable vesicles, is required to maintain transmission upon heavy demand, and is essential for proper memory function…

Here, we examine effects of the steroid hormone, 20-hydroxyecdysone (20-E), on associative olfactory learning in the honeybee, "Apis mellifera." 20-E impaired the bees' ability to associate odors with punishment during aversive conditioning, but did not interfere with their ability to associate odors with a food reward (appetitive…

Synapsin is an evolutionarily conserved, presynaptic vesicular phosphoprotein. Here, we ask where and how synapsin functions in associative behavioral plasticity. Upon loss or reduction of synapsin in a deletion mutant or via RNAi, respectively, "Drosophila" larvae are impaired in odor-sugar associative learning. Acute global expression of…

Through associative learning, cues for biologically significant reinforcers such as food may gain access to mental representations of those reinforcers. Here, we used devaluation procedures, behavioral assessment of hedonic taste-reactivity responses, and measurement of immediate-early gene (IEG) expression to show that a cue for food engages…