MRI benefits students' research

by Ithan Peltan | 5/3/00 5:00am

Dartmouth is the proud owner of a new and powerful tool for the study of neurological function " one of the nation's first functional magnetic resonance imaging scanners to be dedicated solely to research.

The MRI scanner, housed in Moore Hall and managed by the psychological and brain sciences department, was brought online in January and is now being used for a gradually increasing number of research projects.


Professor of psychological and brain sciences and director of the Dartmouth Brain Imaging Center Scott Grafton said the fMRI is the most promising new technology to emerge in the past decade for the study of brain function.

In the past, MR images, generated using magnetic fields 10,000 times stronger than the earth's, were used simply to obtain anatomical information about the brain.

Now, after the discovery that changes in blood flow accompanying increases or decreases in neural activity could be detected using MRI scanners, these functional MR images, or fMRIs, are powerful tools for researchers interested in learning about how the brain works.

By using functional MR scanning to compare resting neurological activity to activity occurring while the research subject performs some action or experiences a stimulus, a variety of types of neurological activity can be studied using the technique.

People employing the fMRI at Dartmouth are researching topics ranging from the function of the brain's frontal lobe in the executive control of social behavior to the effects of culture background on the brain's interpretation of cultural stimuli.

The latter project is being done by psychology professor and Associate Dean of the Faculty Jamshed Bharucha in conjunction with graduate student Petr Janata.

Research subjects of Indian and western descent and upbringing listen to both western and Indian classical and pop music, as well as newscasts in both English and Hindi, while functional MR images are taken at a rate of one image of the entire brain -- 30 slices every two seconds.

The fMRI shows differences between brain activity while subjects are listening to familiar and unfamiliar auditory stimuli.

It is far too soon to have any definite results, Janata said, but a very preliminary look at the data suggests that subjects are more focused " that is, there is less neural activity " when listening to familiar stimuli.

Unique Opportunities

Members of the Dartmouth community are afforded some special opportunities by the $1.2 million research tool in Moore.

Dartmouth is in fact the first college or university in the nation to have an MRI facility specifically for research purposes. Most researchers interested in doing work utilizing the fMRI have to schedule time on a hospital machine, something that is generally difficult, often requiring late and erratic schedules.

Janata said the scanner is a wonderful resource because of the relative ease with which Dartmouth researchers can now schedule time to conduct their fMRI research.

The scanner is also a "core facility" for the College, according to Grafton, one that is available to all faculty and students, not just members of the psychological and brain sciences faculty.

Even undergraduate students will be able to carry out research projects involving the MRI scanner. The requirements for an undergraduate would be the same as those for any other research proposal, simply that the project in question be valuable and well designed.

Grafton suggested that any student interested in using the fMRI should talk to a faculty member to get help in the process of designing the experiment.

"It's an incredible scientific opportunity for students and faculty," Grafton said.

Those interested in seeing the fMRI at work are encouraged to become research subjects and should contact the experiment coordinator, Adriana Vila, by Blitzmail.

The MRI is also in a spot that is particularly free of interference, due to its insulated location, Grafton said.


One of the unique features of Dartmouth's MRI facility a result of its location on campus and the design of the facility containing it.

Located in the basement of Moore and accessible only by stairs and through a thick door with a key-coded lock, the MRI collects data particularly free of electronic interference, Grafton said.

Other accommodations have been made to prevent interference from contaminating the images gathered using the MRI. The room is surrounded by a copper box, which both protects those outside the room from the magnetic field and keeps electronic interference from entering the room and interfering with the scans.

The only way to get sound or visual stimuli into the subject is through a tube, which passes directly through the thick walls, designed to cancel electrical interference attempting to get into the scanner room.

Instead of a window, through which electronic interference could pass with ease, a large, a flat screen television connected to a video camera in the scanner room provides those conducting experiments the scanner room and the research subject. When engaged, the magnetic field is strong enough to distort the image generated by the video camera, located about ten feet from the scanner itself.

In functional mode, the shifting magnetic field is so powerful that it generates a pinging sound as loud as 100 decibels, Grafton said. The sound can be heard through the duct system in the small room in which the experimenter and MRI technician sit. The room contains four computers in addition to the viewing screen. Two perform various experimental functions, one runs the MRI, and the other collects data.

The scanner itself, made by General Electric, sits in the center of a moderately sized room filled with wooden and plastic furniture, and is a typical, tube shaped MRI scanner.

Research subject lay on a platform which moves them into the proper position in the MRI.

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