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Intrinsic signal changes accompanying sensory stimulation: functional brain mapping with magnetic resonance imaging.

1992; National Academy of Sciences; Volume: 89; Issue: 13 Linguagem: Inglês

10.1073/pnas.89.13.5951

1091-6490

Satoshi Ogawa, David W. Tank, Ravi S. Menon, Jutta Ellermann, Seong‐Gi Kim, Hellmut Merkle, Kâmil Uǧurbil,

Functional Brain Connectivity Studies

We report that visual stimulation produces an easily detectable (5-20%) transient increase in the intensity of water proton magnetic resonance signals in human primary visual cortex in gradient echo images at 4-T magnetic-field strength. The observed changes predominantly occur in areas containing gray matter and can be used to produce high-spatial-resolution functional brain maps in humans. Reducing the image-acquisition echo time from 40 msec to 8 msec reduces the amplitude of the fractional signal change, suggesting that it is produced by a change in apparent transverse relaxation time T*2. The amplitude, sign, and echo-time dependence of these intrinsic signal changes are consistent with the idea that neural activation increases regional cerebral blood flow and concomitantly increases venous-blood oxygenation.