Introduction: Vascular reactivity and resting cerebral blood flow (CBF) levels lead to inter-subject variability in functional magnetic resonance imaging (fMRI) studies using the Blood Oxygen Level Dependent (BOLD) contrast to a neural task. This variability is exacerbated in an aging population [1]. Hemodynamic scaling using Resting State Fluctuation Amplitude (RSFA) or Breath hold (BH) can mi...

INTRODUCTION Magnetic field inhomogeneity exist near the interface of air/tissue in the ventral brain (i.e. orbitofrontal cortex), which leads to susceptibility artifacts in fMRI including geometric distortion and signal loss [1-6]. In gradient echo acquisition, the induced susceptibility gradients will also cause echo time shift resulting to BOLD sensitivity changes, especially in the areas co...

Simultaneously acquired EEG and BOLD (Blood Oxygenation level dependent contrast) MRI allowed to study on line the neurophysiological changes in rat brain during epileptic seizures. MRI and EEG data were acquired with a specially designed high quality MR RF-antenna with incorporated non-invasive carbon EEG electrodes. The problem of severe pollution of the EEG data due to MR gradient switching ...

PURPOSE EEG-triggered functional magnetic resonance imaging (fMRI) was used to identify areas of brain activation during spontaneous spike-and-wave discharges (SWDs) in an epileptic rat strain under awake conditions. METHODS Spontaneous absence seizures from 10 WAG/Rij rats were imaged by using T2*-weighted echo planar imaging at 4.7 Tesla. fMRI of the blood-oxygenation-level-dependent (BOLD)...

Although blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) has been widely used to explore human brain function, questions remain regarding the ultimate spatial resolution of positive BOLD fMRI, and indeed the extent to which functional maps revealed by positive BOLD correlate spatially with maps obtained with other high-spatial-resolution mapping techniques ...

We used functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) to study the negative blood oxygenation level dependent (BOLD) signal and its underlying blood flow changes in healthy human subjects. This was combined with psychophysiological measurements to test that the negative BOLD signal is associated with functional inhibition. Electrical stimulation of the medi...

Introduction Low-frequency fluctuations in the blood oxygen level-dependent (BOLD) signal are an important component of ‘physiological noise’ in functional MRI signals. Identification and characterization of these sources is extremely important in order to develop noise reduction strategies and hence obtain more accurate activation maps. Spontaneous low frequency fluctuations in arterial carbon...

The correlation between signals acquired using electroencephalography (EEG) and fMRI was investigated in humans during visual stimulation. Evoked potential EEG and BOLD fMRI data were acquired independently under similar conditions from eight subjects during stimulation by a checkerboard flashed at frequencies ranging from 2-12 Hz. The results indicate highly correlated changes in the strength ...

Concurrent EEG and fMRI acquisitions in resting state showed a correlation between EEG power in various bands and spontaneous BOLD fluctuations. However, there is a lack of data on how changes in the complexity of brain dynamics derived from EEG reflect variations in the BOLD signal. The purpose of our study was to correlate both spectral patterns, as linear features of EEG rhythms, and nonline...

Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is widely used as a measure of neuronal activity, despite an incomplete understanding of the hemodynamic and neural bases for BOLD signals. Recent work by Lee and colleagues investigated whether activating genetically specified neurons elicits BOLD responses. Integrating optogenetic control of specific cells a...