High-speed 3D imaging of cellular activity in the brain using axially-extended beams and light sheets

•Neuroscience needs faster in vivo volumetric microscopy approaches.•Axially-extended beams and light sheets provide alternatives to point scanning.•The performance and photobleaching benefits of axially extended illumination are modeled.•SCAPE microscopy leverages axial benefits for high-speed 3D imaging of neural activity.•SCAPE imaging in awake mouse brain and larval zebrafish brain is demonstrated.