The SEMAINE project will investigate intracranial EEG (icEEG) simultaneously recorded with either fMRI or MEG to 1) improve identification of the epileptogenic zone in patients suffering from drug-resistant partial epilepsy, and 2) define the functional organization of neural networks underlying human perception and cognition in order to prevent inadvertent deficits resulting from neurosurgical resection. In particular, high-frequency activity (HFA), as measured with icEEG, has been demonstrated in recent years as a relevant index for both epileptogenic tissue and healthy cortical processing, but its correlates in fMRI and MEG require further investigation. This will be a pioneering effort in several respects, as the first to directly measure high-frequency neural activity in tandem with fMRI, and among the first to do so with MEG. In addition to their attractiveness as noninvasive imaging techniques, fMRI and MEG have the potential to examine whole-brain networks that are not accessible to icEEG's necessarily limited spatial coverage. Furthermore, such a campaign of simultaneous recordings will take unprecedented advantage of icEEG as the bridge between the two noninvasive techniques, providing compelling evidence for the links between all three measurements with respect to underlying high-frequency neural activity in both health and disease. This project will therefore lead to improved selection of epilepsy surgery candidates and improved neurosurgical outcomes from the precise mapping of epileptogenic and healthy brain networks. The same techniques will be immediately applicable to functional mapping of other types of neurosurgery populations as well as diagnostic neuroimaging of neurological and psychiatric populations.