The Drosophila mushroom body (MB) is a key brain structure essential for learning, memory, and sensory integration. It is composed of a dense network of neurons that undergo a remarkable transformation during metamorphosis, transitioning from a larval to an adult-specific architecture. This restructuring process involves the breakdown of the larval MB calyx, followed by the formation of a new, functionally mature adult version.
Our research focuses on uncovering the molecular and cellular mechanisms that guide this transformation. During metamorphosis, projection neurons establish synaptic connections in loosely defined regions within the calyx, a key site of neuronal integration. Meanwhile, Kenyon cells, the principal neurons of the mushroom body, form non-stereotyped connections in the calyx. Additionally, modulatory neurons, such as the anterior paired lateral (APL) neuron and various dopaminergic neurons, become integrated into the circuit, fine-tuning synaptic communication and plasticity.
Despite the significance of this process, the molecular cues and gradients that orchestrate the precise wiring of the MB calyx remain largely unknown. How do projection neurons navigate this dynamic environment during development? What signals drive Kenyon cells to establish connections and are these specific or generalized? How are modulatory neurons incorporated into this evolving network? These are the fundamental questions we aim to address.
Using advanced genetic tools and live imaging, we will investigate the structural and functional maturation of the MB calyx and the molecular pathways contribute to this. By characterizing the developmental programs that regulate this process, our work will provide crucial insights into the principles of neural circuit formation, not only in Drosophila but also in broader contexts of developmental and systems neuroscience.
This research has far-reaching implications for understanding how neural circuits are established, refined, and maintained, shedding light on fundamental processes that underpin learning, memory, and cognition across species.
Jonathan Smart
JonathanMark.Smart(at)devbiol.rwth-aachen.de
Afra Ercoban
afra.ercoban(at)rwth-aachen.de
Jennifer Bentz
jennifer.betz(at)rwth-aachen.de
Publications:
Baltruschat, L., Prisco, L., Ranft, P., Lauritzen, J.S., Fiala, A., Bock, D.D., Tavosanis, G., 2021. Circuit reorganization in the Drosophila mushroom body calyx accompanies memory consolidation. Cell Rep.
34, 108871. https://doi.org/10.1016/j.celrep.2021.108871.
Marchetti, G., Tavosanis, G., 2019. Modulators of hormonal response regulate temporal fate specification in the Drosophila brain. PLoS Genet.
15, e1008491. https://doi.org/10.1371/journal.pgen.1008491.
Marchetti, G., Tavosanis, G., 2017. Steroid hormone ecdysone signaling specifies mushroom body neuron sequential fate via chinmo. Curr. Biol.
27, 3017-3024.e4. https://doi.org/10.1016/j.cub.2017.08.037.
Christiansen, F., Zube, C., Andlauer, T.F.M., Wichmann, C., Fouquet, W., Owald, D., Mertel, S., Leiss, F., Tavosanis, G., Luna, A.J.F., Fiala, A., Sigrist, S.J., 2011. Presynapses in Kenyon cell dendrites in the mushroom body calyx of Drosophila. J. Neurosci.
31, 9696–9707. https://doi.org/10.1523/JNEUROSCI.6542-10.2011.
Kremer, M.C., Christiansen, F., Leiss, F., Paehler, M., Knapek, S., Andlauer, T.F.M., Förstner, F., Kloppenburg, P., Sigrist, S.J., Tavosanis, G., 2010. Structural long-term changes at mushroom body input synapses. Curr. Biol.
20, 1938–1944. https://doi.org/10.1016/j.cub.2010.09.060.
Leiss, F., Groh, C., Butcher, N.J., Meinertzhagen, I.A., Tavosanis, G., 2009a. Synaptic organization in the adult Drosophila mushroom body calyx. J. Comp. Neurol.
517, 808–824. https://doi.org/10.1002/cne.22184.
