Our group aims at understanding the molecular and biochemical mechanisms, by which the brain adapts local blood flow to neuronal activity and cellular metabolism with high temporal and spatial resolution. A tight relation exists between neuronal and glial cell activation, cerebral energy metabolism, and cerebral vasculature – a phenomenon known as neurometabolic and neurovascular coupling. This tight coupling of electrical and metabolic activity and regional cerebral blood flow is characteristic for the brain. Increased neuronal and thereby metabolic activity of the cerebral cortex during functional activation is accompanied by a transient increase in local cerebral blood flow and by vascular hyperoxygenation. It can be suggested that neurovascular coupling is tight and rapid, possibly serving to protect brain tissue from any period of hypo-oxygenation. The central topis are: How does the vasculature serve brain function? How do neurons and blood vessels communicate? What specifically makes neurons run? In disease impaired cerebrovascular regulation leads to a mismatch of regional cerebral blood flow and metabolic demand which may itself contribute to tissue damage. We are investigating the 'fingerprints' and mechanisms of pathophysiological processes in vascular reactivity, cerebral blood flow or hemoglobin oxygenation as the basis for new diagnostic and therapeutic strategies in acute and chronic CNS disorders with a special focus on subarachnoid hemorrhage.