Jack Belliveau, associate professor in radiology at Harvard Medical School, died at the age of 55 on Feb. 14.

Belliveau provided a major breakthrough in his field and went on to mentor many of today’s researchers.

Most recognized for his discovery of the functional magnetic resonance imaging, or fMRI, technique in 1991, Belliveau was a leader of his field. He served as a research fellow at the Massachusetts General Hospital in the Nuclear Magnetic Resonance Center, using dynamic susceptibility MRI with a contrast agent to measure the changes in blood volume in various regions of the brain.

Unlike the EEG, which measures electric signals, this novel method allowed scientists to practice advanced techniques.

“[These were] exquisite things we didn’t even think of 20 years ago,” said colleague Tom Brady, director of the Center at the time.

With the new technique, neurobiologists could get clear images of the brain and observe which sections of it reacted to different activities.

“It was a very hard problem and people weren’t at all convinced it can be done,” said Bruce Rosen, former advisor and professor of radiology at the Medical School. “So, when Jack stood up as a graduate student and presented these findings…a lot of people took notice that otherwise had been somewhat dismissive of this possibility.”

Following the discovery, Belliveau presented the study to the Society for Magnetic Resonance in Medicine in San Francisco, where he won the Young Investigator Award.

The discovery provided clearer images of the brain that would later enable postdoctoral fellow Kenneth Kwong to use endogenous contrasts and to create a safer human fMRI. His discovery changed the field of neurobiology.

“Jack was a lightning rod that inspired a generation of neuroscientists,” Brady said.

The Boston Globe reported that Belliveau died of complications with a gastrointestinal disorder, according to his wife, Brigitte Poncelet-Belliveau.

However, Belliveau’s passion extended beyond these technological advances and lead him to further research.

“His dream was to record the human consciousness,” said Jyrki Ahveninen, who met Belliveau as a postdoctoral student, and is now an assistant radiology professor at the Medical School.

Until his death, Belliveau led a group of investigators at MGH studying the visual and auditory systems using multi-modal imaging tools. He also attempted to increase the temporal resolution of fMRI so that it could capture images at a much faster rate.

“Though many labs use fMRI, Jack came to realize—even having invented the tool—that it had certain limitations,” Rosen said. “So he had set out to bring other technologies to bear to study the brain.”