Mechanisms underlying homeostatic plasticity in the Drosophila mushroom body in vivo

Significance When a neuron fires, it excites or inhibits other neurons. These two opposing forces—excitation and inhibition—need to be carefully balanced in the brain for neural networks to function properly. Maintaining this balance requires homeostatic plasticity to compensate for perturbations in neural activity levels. Relatively little is known about how such homeostatic compensation works in the intact central brain in vivo. To address this problem, we developed a model for studying homeostatic plasticity in vivo: theDrosophila mushroom body (the fly’s olfactory memory center). We found that this brain structure compensates for prolonged excess inhibition through a combination of increased excitation and decreased inhibition, with these two mechanisms contributing differently for different types of neurons.