Understanding the neural circuity of social spacing behaviour through the lens of Drosophila Neuroligin 3
Authors: John Robinson; Abigail Bechard; Ryley Yost; Anne Simon
Affiliation: Western University
Keywords: r. circuits; e. synaptic function and organization
The neural circuitry underlying Drosophila social behaviours has become an increasing field of study. Drosophila exhibit social behaviours when in proximity to other individuals and settle at a defined social space. Determination of social spacing could be attributed to many factors such as social experience, genetics, or differential signalling of neural circuitry. So far, we and others have determined that the mushroom bodies (MB) of the Drosophila brain are important for social space. As well, synaptic proteins including Rugose a scaffolding protein at the postsynaptic density, Narrow-abdomen a channel at the presynaptic terminal, and proteins involved with dopamine synthesis and vesicle loading all play a role in social space - highlighting the importance of synaptic functioning on this behaviour. The manipulation of global dopaminergic signalling also alters social space in a sexually dimorphic manner; however, we do not know how dopamine signalling, synaptic proteins, and the MB are all connected to modify fly social spacing. Here, we show that a deficiency of neuroligin 3 (nlg3), a gene encoding a post-synaptic protein that regulates transmission at the synapse, modifies social space. Neuroligin 3 is also found to be enriched in the MB, protocerebral bridge, and optic lobes regions of the brain. Hyperactivation and silencing of fruitless neurons recapitulates the sexually dimorphic effect we previously observed in fly social spacing, so lastly we targeted a dopaminergic knockdown within the P1 subset of fruitless neurons. Our results contribute to understanding the role of specific neural circuitry in modulating the social spacing behaviour of Drosophila.