  Fast confocal imaging was achieved by combining remote focusing with
differential spinning disk optical sectioning to rapidly acquire images of live
samples at cellular resolution. Axial and lateral full width half maxima less
than 5 um and 490 nm respectively are demonstrated over 130 um axial range with
a 256 x 128 um field of view. A water-index calibration slide was used to
achieve an alignment that minimises image volume distortion. Application to
live biological samples was demonstrated by acquiring image volumes over a 24
um axial range at 1 volume/s, allowing for the detection of calcium-based
neuronal activity in Platynereis dumerilii larvae.
