Periodic Reporting for period 3 - OlfSwitch (OlfSwitch: Neural circuit switches from molecules to behaviour)
Reporting period: 2018-07-01 to 2019-12-31
Our work principally uses the fruit fly (Drosophila melanogaster). This has a tiny brain with just 100,000 neurons (one thousand times fewer than a mouse, one million times fewer than a human) but is nevertheless capable of many sophisticated behaviours. Furthermore we can identify and manipulate the same neurons from one fly to the next using genetic tools. This allows us to study how they encode information about the outside world, how this contributes to behaviour and how particular circuit motifs are specified during brain development by the action of control genes. This grant will focus on the processing of smells, because they require little brain processing before contributing to decision processes. We will focus on sexually dimorphic circuits and on pathways mediating unlearned responses to different kinds of odours. This will enable us to understand how genes can sculpt circuits to specify different behaviours and how signals with opposite or similar behavioural significance are integrated in the brain. We can address these issues with great precision in the fly brain, but we feel that are results are very likely to reveal principles conserved across species.
We have developed approaches to measure gene expression in identified neurons down to the level of single cells. We are now using this to identify the genes expressed in our neurons of interest and determine how gene expression differs between males and females.
We have made substantial progress in setting up sophisticated behavioural apparatus so that we can carry out highly quantitative studies of behaviour in wild type and experimentally manipulated animals.
We have also made significant progress in integrating light and electron microscopy data. This now enables us to carry out EM tracing in collaboration with the newly established connectomics group in the University of Cambridge Zoology Department and colleagues at HHMI Janelia Research Campus in the USA. This has already revealed new and unexpected connectivity in both sexually dimorphic and general odour circuits. We are now planning functional investigation of these results.