Genetic targeting of neuronal cells with activity reporters (calcium or voltage indicators) has initiated the paradigmatic transition whereby photons have replaced electrons for reading large-scale brain activities at cellular resolution. In parallel, optogenetics has demonstrated that targeting neuronal cells with photosensitive microbial opsins, enables the transduction of photons into electrical currents of opposite polarities thus writing, through activation or inhibition, neuronal signals in a non-invasive way1. These progresses have in turn stimulated the development of sophisticated wave front shaping approaches, based on computer generated holography and temporal focusing, to enable in depth “all optical” brain circuits interrogation with high spatial and temporal resolution2: an essential methodology to link neuronal circuits activity to the control of memory, learning and perception in pathological and healthy brain. Here, we will review the working principles of all-optical methods and will show few breakthrough applications where they have been used for the investigation of visual circuits in mice models.