Understanding how the brain works in tight concert with the rest of the central nervous system (CNS) hinges upon knowledge of coordinated activity patterns across the whole CNS. We present a method for measuring activity in an entire, non-transparent CNS with high spatiotemporal resolution. We combine a light-sheet microscope capable of simultaneous multi-view imaging at volumetric speeds 25-fold faster than the state-of-the-art, a whole-CNS imaging assay for the isolated Drosophila larval CNS and a computational framework for analysing multi-view, whole-CNS calcium imaging data. We image both brain and ventral nerve cord, covering the entire CNS at 2 or 5 Hz with two- or one-photon excitation, respectively. By mapping network activity during fictive behaviours and quantitatively comparing high-resolution whole-CNS activity maps across individuals, we predict functional connections between CNS regions and reveal neurons in the brain that identify type and temporal state of motor programs executed in the ventral nerve cord.
In this study the authors monitor neural activity as animals move demonstrate functional imaging of an entire, complex CNS. They use light-sheet microscopy that enables high-speed multi-view functional imaging with one- or two-photon excitation
They coupled this with a calcium sensor that allowed activation of nerves to be seen. They have looked at the fruitfly larvae as it crawls
It is becoming increasingly clear that to understand how neuronal networks function, it is important to measure neuronal network activity at the system level. This method enables, for the first time, the imaging of activity within the entire CNS of a widely used genetically tractable model organism as it generates multiple behaviours and lays the foundation for a studies and analysis of neural activity.