Abstract
BACKGROUND: Progress in neuroscience depends substantially on the ability to establish the detailed spatial and temporal sequence of neuronal population-level activity across large areas of the brain. Because there is substantial inter-trial variability in neuronal activity, traditional techniques that rely on signal averaging obscure where and when neuronal activity occurs. Thus, up to the present, it has been difficult to examine the detailed progression of neuronal activity across large areas of the brain. NEW METHOD: Here we describe a method for establishing the spatiotemporal evolution of neuronal population-level activity across large brain regions by determining exactly where and when neural activity occurs during a behavioral task in individual trials. We validate the efficacy of the method, examine the effects of its parameterization, and demonstrate its utility by highlighting two sets of results that could not readily be achieved with traditional methods. RESULTS: Our results reveal the precise spatiotemporal evolution of neuronal population activity that unfolds during a sensorimotor task in individual trials, and establishes the relationship between neuronal oscillations and the onset of this activity. CONCLUSIONS: The ability to identify the spatiotemporal evolution of neuronal population activity onsets in single trials gives investigators a powerful new tool with which to study large-scale cortical processes.