Oscillations represent basic operational modes of the human brain. They reflect local field potential activity generated by the laminar arrangement of cell-type specific microcircuits interacting brain-wide under the influence of neuromodulators, endogenous processes and cognitive demands. Under neuropathological conditions, the spatiotemporal structure of physiological brain oscillations is disrupted as recorded by electroencephalography and event-relate potentials. Such rhythmopathies can be used to track microcircuit alterations leading not only to transient pathological activities such as interictal discharges and seizures but also to a range of cognitive co-morbidities. Here we review how basic oscillatory modes induced in human brain slices prepared after surgical treatment can help us to understand basic aspects of brain function and dysfunction. We propose to overcome the traditional view of examining human brain slices merely as generators of epileptiform activities and to integrate them in a more physiologically-oriented oscillatory framework to better understand mechanisms of the diseased human brain.