Functional and metabolic MRI techniques have been rapidly evolving and have tremendous potential for clinical brain disorders research. Clinical activation fMRI studies are performed at 1.5 and at 3.0 Tesla using blood oxygenation level dependent (BOLD) contrast method and arterial spin tagging (AST) techniques. Reproducible alterations Cerebral Blood Flow (CBF) have been performed having healthy controls inhale carbogen at 6% carbon dioxide with an approximate increase of 20-30% in CBF. These preliminary studies allowed us to perform pharmacological challenges using a cyclo-oxygenase inhibitor (COX) 1, indomethicin, and have demonstrated an almost complete suppression of the alteration of CBF to 6% carbon dioxide in subjects at rest. Plans are to evaluate the changes in CBF to other COX inhibitors to determine the response of the cerebral endothelial cells. In addition, we are planning to perform these studies during sensori-motor task activation in order to determine if COX ?1 and COX-2 drugs to suppress the CBF response with stimulation. Future, work will focus on improving the AST pulse sequences with background suppression to provide coverage over the whole head and also move the techniques to higher field strengths.