Correlated activity in the CNS: a role on every timescale?

Until recently, correlated neuronal activity was seen by many as an arcane subject, of interest only to those with mathematical minds and access to elaborate electronics. However, the list of situations in which correlated activity is known or strongly suspected to be highly influential now embraces almost every branch of neuroscience, including perception, memory and the development and plasticity of structural and functional linkages throughout the CNS. Previous reviews in TINS have covered several specific roles of correlated activity in detail. Here, my aim is to explore their diversity, emphasizing the organizing potential of correlation across timescales ranging from the momentary to the evolutionary.