A fundamental scientific problem of our time is to understand how brains integrate present sensory stimuli, past experience, and future behavioral options. This research unit wants to understand how adaptive behavior is organized through the properties of single neurons, their synapses, and the neural circuits the neurons are part of.

Previous research has treated these three levels largely in separation. A combination of new tools such as optogenetics, cell-specific transgene expression, connectomics and modeling now paves the way to understand brains as integrated systems for the control of behavior. For such an endeavor, the fruit fly Drosophila melanogaster is particularly suitable. It combines brain simplicity, behavioral richness, and experimental accessibility. As a paradigmatic case of how a central brain structure brings about adaptive behavior, this research unit focuses on the mushroom body.

The mushroom body is an evolutionary ancient third-order brain structure, comprising but 2500 neurons. It integrates input from multiple sensory modalities with modulation through multiple biogenic amines and signaling peptides. Its output then is integrated with innate behavioral tendencies to bring about adaptive behavior. Interestingly, the mushroom body features structural, functional, and developmental similarity with mammalian brain structures as diverse as cortex, cerebellum and hippocampus. Thus the mushroom body is an ancient, leanly designed, functionally dense, multi-purpose organizer of adaptive behavior. As such, it can be seen as a paradigmatic case of how a brain operates.

We use an integrative approach to brain function that is possible only within the framework of a research unit involving a team of laboratories with different expertise. The research unit is composed of six laboratories located at four Universities, one Institute of the Helmholtz Association and one Leibniz-Institute. Research projects cover fundamental aspects that, as a whole, lead to a more comprehensive model of brain function. Therefore, the research unit provides a unique chance to synergistically merge our expertise in order to understand how a central brain structure contributes to selecting, producing and controlling behavior. In order to abstract the operating principles of such a brain structure, the research unit embraces theoretical and computational approaches. This will be fruitful not only to understand fundamental operating principles of brains as such. Understanding a simple, time-tested system such as the Drosophila mushroom body further has the long-term potential to inspire the design of adaptively behaving technical devices.