The University of California, San Diego has received a $2 million grant from the W. M. Keck Foundation to help equip a new UCSD Center for Functional Magnetic Resonance Imaging.
This regional, state-of-the-art facility, developed in collaboration with The Salk Institute, will enable researchers to conduct sophisticated studies of both the structure and function of the brain. In recognition of the grant, the facility housing the 6,500 square-foot Center, now under construction on the UCSD campus, will be named the W. M. Keck Building.
The new Center will provide neuroscience, medical, and cognitive science researchers in the San Diego region with the facilities needed to develop new imaging technologies, uncover the neural basis of human cognition, and provide new avenues for treating human brain disorders. It will be the largest and most comprehensive brain imaging facility dedicated to research in the Western United States.
Four different imaging systems will help investigators better understand the physiological processes that make the brain a multi-task control center. It will make possible sophisticated studies of behavior, perception, memory, and language, as well as advancing our understanding of abnormal functions of the brain in disorders such as stroke and epilepsy, and degenerative diseases such as Alzheimer’s and Parkinson’s.
“Despite the widespread use of functional magnetic resonance imaging (fMRI) for brain research, the physiological mechanisms underlying the fMRI signal are still poorly understood,” says Richard Buxton, Ph.D., the Center’s director and a UCSD professor of radiology. “Because of this, fMRI is currently limited to answering the question of ‘where is the brain active?’ during particular tasks. As we better understand how fMRI works, we hope to answer the more important questions such as ‘how does brain activity change in disease?’”
What scientists currently know is that fMRI provides detailed pictures of brain anatomy and detects activated areas of the brain by measuring increased blood flow and volume. When individuals use their brains, neurons and supporting structures require oxygen and nutrients to provide energy for optimal brain function. To provide that oxygen, blood flow increases to areas of the brain used for specific actions such as listening, speaking, and moving.
“But do the events we witness always happen the same way?” Buxton asks. “Is it the same in children as adults? Does it change with neurodegenerative disease? Our uncertainty makes it difficult to optimally interpret fMRI results.”
Buxton and several other researchers hope to answer these and other questions as they seek a better understanding of the fMRI signal. In addition, they plan to develop technology to improve the quality and interpretability of fMRI data, and explore methods for integrating fMRI data with measurements such as the electroencephalogram (EEG).
The UCSD Center for Functional Magnetic Resonance Imaging also will provide opportunities for students at UCSD and surrounding institutes to observe and participate in pioneering research. Students from such diverse fields as neuroscience, bioengineering, biology, psychology, and medicine will benefit.
The W. M. Keck Foundation is one of the nation's leading philanthropic organizations. Established in 1954, it is known for supporting pioneering research in medicine, science, and engineering. In addition to its research grants in the physical and life sciences, its giving includes major support for the Keck Observatory in Hawaii, the Distinguished Young Scholars in Medical Research Awards, and grants for early learning programs for children.
Additional information about UCSD research designed to provide a quantitative understanding of the mechanisms that produce fMRI signal and to develop new technological approaches for improving imaging capabilities:
Richard Buxton, Ph.D., director, UCSD Center for Functional Magnetic Resonance Imaging and a UCSD professor of radiology, has utilized UCSD’s clinical MRIs to develop models that link the brain’s requirements for oxygen to changes in blood flow. Developed in collaboration with UCSD associate professors of radiology Lawrence Frank, Ph.D., and Eric Wong, Ph.D., the oxygen limitation model provides a possible explanation for why the blood flow increase must be large in order to support a small change in oxygen metabolism. This work was the first model to provide a quantitative explanation of this phenomenon. Buxton notes that continuation of the research requires the higher magnetic field-strength of the new fMRI devices.
Another problem being tackled by UCSD researchers is a determination of how changes in arterial blood flow and oxygenation produce changes in the intensity of the magnetic resonance images. Because fMRI signal changes depend on changes in blood flow, blood volume and oxygen metabolic rate, Wong, Buxton and Frank are developing new techniques that are sensitive only to the change in blood flow or only to the change in blood volume.
The development of technology to improve the quality and interpretability of fMRI data is a major thrust of the center’s researchers. For example, Wong is an expert in the development of customized scanner accessories called gradient and radio frequency coils that improve the speed, resolution and stability of image acquisition as well as the sensitivity, or signal to noise ratio, of the images.
A novel area of hardware research that Wong is beginning to explore is the design of local shim coils that adjust the uniformity of the main magnetic field. Non-uniformities in this field, which are caused by differences in the magnetic susceptibility of different tissues, are the dominant source of image artifacts in most fMRI imaging techniques and may be alleviated by this relatively unexplored class of coils.
FMRI researchers also are looking at experimental design and analysis, new visualization tools for brain mapping, and ways to integrate fMRI with other measurements such as EEG and MEG, which pick up small electrical and magnetic field changes on the scalp evoked by neuronal responses.