"How does cognition result from complex neuronal interactions within and between brain regions? Substantial progress has been made understanding the functional properties of individual neurons, but we lack understanding of how they work together. Neuronal oscillations are ubiquitous in the brain. The frequencies of these oscillations reflect the biophysical properties of underlying circuit interactions. Thus, frequency-specific oscillations may serve as ‘spectral fingerprints’ of specific circuit interactions. However so far, the circuit interactions underlying cortical oscillations are largely unknown.The key objective of my proposal is to establish this ‘spectral fingerprint’ framework for the human brain, by identifying elementary circuit interactions underlying non-invasive M/EEG oscillations. We will employ a novel interdisciplinary approach that tightly links human and monkey electrophysiology.First, we will perform directly comparable EEG (and MEG) recordings in humans and monkeys using identical behavioural tasks to identify consistent local and large-scale oscillations in both species. Second, we will characterize the neuronal circuit interactions underlying these non-invasive oscillations in monkeys using simultaneous EEG and intra-cortical recordings as well as electrical and pharmacological manipulations.If successful, this work will constitute a paradigm shift in cognitive neuroscience by linking two largely disconnected disciplines: human and monkey electrophysiology. Identifying spectral fingerprints of elementary circuit interactions will establish a powerful new framework to understand cognitive processes in terms of mechanistic, network-level building blocks."