In this advanced course the concept of hierarchy is going to be explored from the point of view of theoretical and experimental neuroscience as well as from a machine learning perspective. In lecture-driven talks we will review what is known and discuss which are the open and most relevant questions at the field. Specifically how theoretical neuroscience and machine learning integrate hierarchy to describe neuronal networks and which are the anatomical and behavioral data supporting the existence of such in the nervous system. Participants will be presented with a historical frame of reference on hierarchy in neural networks (day one), hierarchical coding or hierarchy of sensory systems (day two) and finally hierarchical neural networks in the context of behavior (or solving a task/action/decision making).