The Not-So-Global Blood Oxygen Level-Dependent Signal

The neural basis of the blood-oxygen-level-dependent functional magnetic resonance imaging signal.

Magnetic resonance imaging (MRI) has rapidly become an important tool in clinical medicine and biological research. Its functional variant (functional magnetic resonance imaging; fMRI) is currently the most widely used method for brain mapping and studying the neural basis of human cognition. While the method is widespread, there is insufficient knowledge of the physiological basis of the fMRI ...

Can Blood Oxygen Level-Dependent Imaging Depict the Ischemic Penumbra?

Blood oxygen level-dependent signal variability is more than just noise.

Functional magnetic resonance imaging (fMRI) research often attributes blood oxygen level-dependent (BOLD) signal variance to measurement-related confounds. However, what is typically considered "noise" variance in data may be a vital feature of brain function. We examined fMRI signal variability during fixation baseline periods, and then compared SD- and mean-based spatial patterns and their r...

Regional dynamic signal changes during controlled hyperventilation assessed with blood oxygen level-dependent functional MR imaging.

PURPOSE To quantitate the amplitude changes and temporal dynamics of regional functional MR imaging signals during voluntary hyperventilation using blood oxygen level-dependent contrast echo-planar imaging. METHODS Seven male subjects were studied during voluntary hyperventilation (PetCO2 = 20 mm Hg) regulated by capnometry. Measurements were made on multisection echo-planar MR images obtaine...

Relative language proficiency modulates BOLD signal change when bilinguals perform semantic judgments. Blood oxygen level dependent.

The effect of relative language proficiency on the spatial distribution and magnitude of BOLD signal change was evaluated by studying two groups of right-handed English-Mandarin bilingual participants with contrasting language proficiencies as they made semantic judgments with words and characters. Greater language proficiency corresponded to shorter response times and greater accuracy in the s...