Brain Premotor Centers for Pheromone Orientation Behavior

Moths use sophisticated olfactory navigation tactics for resource localization. We herein discuss the neuronal mechanisms that generate locomotor command for pheromone-source localization in the silkmoth Bombyx mori. Flip-flop neural signal, a state-dependent persistent firing activity, which is observed in the area of the insect brain called the lateral accessory lobe, correlates with turning behavior during pheromone orientation. We describe the morphology and physiology of basic neuronal components in the circuit, and provide a comparative view of its organization. We also describe neurons in the posterior slope, which contains a population of neurons descending toward the body ganglia. Mechanisms that generate flip-flop signals are also discussed.