Plasticity and adaptation as occur in learning and some forms of disease could shift neurons outside their working range. We are investigating the functional and molecular properties of homeostatic control mechanisms that stabilize neuronal excitability. We study scaling mechanisms at the single cell and at the network level. The involvement of Ca2+ dynamics in the process, the role of oscillations and memory consolidation are evaluated. Furthermore we investigate scaling deregulation in the diseased brain, particularly in epileptogenesis. The neurophysiological experiments are supported by mathematical and computational modeling.