The purpose of these studies is to develop and improve techniques for the magnetic resonance imaging of physiological function. These studies have concentrated on the human brain and heart using a variety of imaging sequences on the laboratory's 4 Tesla whole body MRI system. In the brain, studies of cerebral perfusion and neuronal activity have been carried out, and in the heart, images of cardiac motion at various points in the heart cycle have been obtained. Blood oxygenation level dependent contrast (BOLD) has been used as a means for obtaining time series data sets during periods of neuronal stimulation in the brain. This technique has been used to study the effect of long term learning of a motor task in the primary motor area. The finding is that changes specific to a learned sequence of motor movements are visible, causing a larger representation in M1 for a learned sequence. Improvements to image quality have been realized by better image reconstruction strategies, and methods to correct for serious geometric distortions in echo planar images have been devised. In the heart, new sequences, such as segmented spiral and segmented multi-echo GRASS have been implemented and have resulted in satisfactory images.
