Behavioral functions of the insect mushroom bodies.

New methods of intervention in Drosophila and other insect species reveal that the mushroom bodies are involved in a diverse set of behavioral functions. The intrinsic Kenyon cells (those neurons with projections within the mushroom bodies) house part of the short-term memory trace for odors and are required for courtship conditioning memory. A pair of extrinsic mushroom body neurons (neurons with projections both inside and outside the mushroom bodies) provides a neuropeptide important for 1-hour olfactory memory. In addition, the mushroom bodies are necessary for context generalization in visual learning and for regulating the transition from walking to rest.