Slow-wave oscillatory activity is critical for several fundamental processes from general brain homeostasis to memory consolidation. Further, there is increasing evidence in support of SW activity alterations in different brain diseases. In this project, the long-term goal is to correlate the delicate equilibrium between excitatory and inhibitory neurons, mirrored into patterns of propagating waves, and large-scale functional connectivity in different brain states (awake, anesthetized, natural sleep). By using a combination of optical imaging (wide-field and two-photon microscopy) and electrophysiology (EEG) techniques we aim to characterize these oscillations at the level of the entire cortical mantle and, in parallel, to inspect how this propagating global activity relates to the balanced activity of excitatory and inhibitory neurons. Genetically-encoded calcium indicators are used in combination with light-inducible actuators to causally dissect the features of cortical activation in the low-frequency bands. Theoretical models are built and validated on these multi-scale data to infer mechanistic insight. Finally, we plan to apply this knowledge to dissect salient features of aberrant cortical functionality in mouse models of developmental disorders.