Development of functional imaging in the human brain (fMRI); the University of Minnesota experience

Abstract

The human functional magnetic resonance imaging (fMRI) experiments performed in the Center for Magnetic Resonance Research (CMRR), University of Minnesota, were planned between two colleagues who had worked together previously in Bell Laboratories in the late nineteen seventies, namely myself and Seiji Ogawa. These experiments were motivated by the Blood Oxygenation Level Dependent (BOLD) contrast developed by Seiji. We discussed and planned human studies to explore imaging human brain activity using the BOLD mechanism on the 4 Tesla human system that I was expecting to receive for CMRR. We started these experiments as soon as this 4 Tesla instrument became marginally operational. These were the very first studies performed on the 4 Tesla scanner in CMRR; had the scanner become functional earlier, they would have been started earlier as well. We were aware of the competing effort at the Massachusetts General Hospital (MGH) and we knew that they had been informed of our initiative in Minneapolis to develop fMRI. We had positive results certainly by August 1991 annual meeting of the Society of Magnetic Resonance in Medicine (SMRM). I believe, however, that neither the MGH colleagues nor us, at the time, had enough data and/or conviction to publish these extraordinary observations; it took more or less another six months or so before the papers from these two groups were submitted for publication within five days of each other to the Proceedings of the National Academy of Sciences, USA, after rejection by Nature in our case. Thus, fMRI was achieved independently and at about the same time at MGH, in an effort credited largely to Ken Kwong, and in CMRR, University of Minnesota in an effort led by myself and Seiji Ogawa.

Figure 1

(a) and (b) are the images that were published as Figure 2 in the Ogawa et. al. 1992 paper; panel (b) shows the full-field visual stimulation functional image (in color) superimposed on the anatomical image in gray scale; the latter is presented also separately in panel (a). Panel (c) illustrates a functional image of hemifield visual stimulation (on minus off) from 1991, obtained with 4 mm slice and in plane resolution 1.4×1.4 mm². The signal intensity trace along the line marked with the yellow arrow appears on top of the image

Figure 2

The picture shows the author next to the 125 cm bore 4 Tesla magnet from Siemens that was originally installed in CMRR in 1990. This magnet is now a garden “statue” in the courtyard of CMRR, University of Minnesota.