Postsynaptic receptor plasticity and transsynaptic communication in storage of memory components in the mushroom bodies

Memories typically represent multifaceted experiences, with individual components likely represented as parallel traces. In Drosophila, it is well established that, in general, differential olfactory conditioning paradigms give rise to memories stored as synaptic changes at the level of the mushroom bodies (MBs). While it is conceivable that differential conditioning will give rise to individual separate memories, and consequently molecular memory traces representing the presence of a reward or a punishment or the absence of either, how and where these individual facets are stored remains unclear. This proposal builds on (1) our previous work identifying two distinct MB output compartments involved in either appetitive or aversive memory storage and (2) our recent discovery of postsynaptic plasticity that exists next to presynaptic mechanisms in the context of appetitive memories. We will address the hypothesis that each MB output compartment can store both, an aversive and an appetitive trace, by utilizing the postsynaptic alongside the presynaptic compartment, to encompass information for instance representing the presence and the absence of a reward. Using absolute conditioning in combination with in vivo functional and receptor imaging protocols that we developed over the last years, we will address mechanisms of postsynaptic receptor plasticity in the context of aversive and appetitive memories. We will further investigate potential transsynaptic interplay during memory formation by targeted intervention of postsynaptic receptors or the presynaptic protein composite.