The capacity to capture the nervous activity of an entire central nervous system (CNS) of a developing fly is reported in Nature Communications this week. A framework that combines high speed microscopy and computational tools enables the simultaneous imaging of neural activity across the entire, isolated larval CNS of the fruit fly Drosophila melanogaster.

Recent advances in imaging technology such as light-sheet microscopy have enabled high-speed, high-resolution, three-dimensional imaging of large volumes of neural tissue. Thanks to these advances, together with the development of improved technology for detecting neuronal activity from specific cellular populations, it has become possible to record activity from every part of a nervous system while animals perform specific actions. Up to now, however, the technology had not been applied to imaging the entire central nervous system of a relatively large model organism such as the developing fruit fly.

Philipp Keller and colleagues have now introduced a number of methodological improvements in sample preparation, neural activity imaging and image analysis that enabled them to image the entire CNS of the fly larva after it had been isolated. Using this approach, they were able to image coordinated motor activity patterns throughout the CNS for up to an hour, while imaging the entire CNS 5 times per second.

Paired with methods that interfere with neural activity and methods that obtain detailed spatial maps of the structure of the nervous system and its connections, this type of methodology will help advance the understanding of the neuronal networks that dictate animal behaviour.