Life is a multisensory experience for most animals. Learning to associate and bind different sensory features into a scene is a fundamental process of the brain, which improves subsequent memory performance. However, neural mechanisms that bind sensory features during learning remain to be explained. Using Drosophila melanogaster, we developed a new experimental learning and memory paradigm in which visual and olfactory cues are combined. Flies trained with combinations of both modalities show improved memory performance, even when the sensory cues are presented separately during testing. We used temporal control of neuronal function to define the components of the mushroom body memory network that are required for multisensory learning and performance enhancement. Voltage imaging in head-fixed flies revealed that dopaminergic reinforcement and serotonergic signalling during multisensory learning binds activity in streams of modality-specific mushroom body neurons. This broadening of the engram improves memory performance after multisensory learning and permits a single sensory feature to retrieve the memory of the multimodal experience.
Zeynep Okray joined the University of Oxford in 2017 as an EMBO postdoctoral fellow in Scott Waddell's laboratory, at the Centre for Neural Circuits and Behaviour. Her main research interest lies in how a defined set of neural circuits can encode for and accommodate different types of memory. Zeynep obtained her undergraduate degree from the University of Chicago and her doctorate from the University of Leuven/VIB, where she worked in the laboratory of Bassem Hassan, focusing on the genetic mechanisms of Fragile X Syndrome. Zeynep is passionate about leveraging the power of the fruit fly model (Drosophila melanogaster) to address fundamental questions exploring brain function.