With the Femto3D Atlas events less than a millisecond apart can be separated, and therefore propagation speed of regenerative activity determined at multiple sites of the dendritic tree. Random-access point scanning is a usable method also for measuring dendritic activity, however, random-access point scanning extended by drifting the focal point along short 3D trajectories allows imaging without interruption at multiple dendritic branches. The sampling is continuous during the drift, so this scanning mode gives a more detailed spatial resolution without changing the overall scanning time: this remains as high as during the point scanning. As a result, the function of thin dendritic segments, or even spines and single action potentials can be revealed. See also Katona et al., Nat Meth, 2012; Chiovini et al., Neuron, 2014.