Abstract
Functional magnetic resonance imaging (fMRI) relies on the well-known phenomenon of coupling between neuronal activity and brain blood flow. For nearly a century, the presumption was that hemodynamics were coupled to neuronal activity via energy demand and oxidative metabolism. Early 15O positron-emission tomographic (PET) studies challenged this theory, demonstrating a physiological "uncoupling" between brain blood flow and oxygen metabolism. These PET observations played a pivotal role in guiding the development of fMRI, by demonstrating which physiological parameters were most closely coupled to neuronal activity and by presaging the BOLD-contrast effect. Subsequent PET studies were crucial for constraining theories concerning the physiological mechanisms underlying hemodynamic/neuronal coupling and, thereby, guiding the development of models for quantification of oxygen metabolic rate %{increment} from fMRI. A first-person account of the PET "coupling" studies and their influence on the development of fMRI is provided.
Original language | English (US) |
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Pages (from-to) | 594-601 |
Number of pages | 8 |
Journal | NeuroImage |
Volume | 62 |
Issue number | 2 |
DOIs | |
State | Published - Aug 15 2012 |
Keywords
- CBF
- CMRO
- Cerebral blood flow
- Cerebral metabolic rate
- Coupling
- FMRI
- PET
ASJC Scopus subject areas
- Neurology
- Cognitive Neuroscience