The two-day symposium "Neuronal circuit dynamics across scales and species" is organised to celebrate the 15th anniversary of the Neuroscience Center and the establishment of the new greater-Helsinki region brain-research organisation Helsinki Brain Center. It follows the Neuroscience Finland 2018 Symposium organized by the Brain Research Society of Finland (https://www.brsf.org/nf2018) on 2 May 2018. Symposium topics include the usability and limitations of different animal models for understanding human brain functioning, research paradigms that enable cross-scales and inter-species comparisons, and inter-species differences and similarities in brain dynamics. Registration is open and limited to 200. We also welcome abstract submissions for poster presentations in the domains of the symposium.