Currently, the studies of electrical activity and plasticity of neuronal networks are impossible without employing of imaging techniques to visualize functional signals that allowing revealing electrical events in multiple neurons, as well as in their tiny dendrites and axons placed on their morphological picture. Imaging with voltage-sensitive dyes (VSD) is one of unique available methods that providing both high spatial resolution and ultrafast sampling (< 0.1 ms) in realtime with perfect S-to-N ratio. During the last decade a significant progress in VSD application has been achieved due to major method improvements and new probe synthesis especially in the field of research of initiation and propagation of action potentials. There was evidence of the method efficiency and usability while the method was added to the toolbox of modern neuroscience for research in hottest topics.