Since the functional magnetic resonance imaging (fMRI) signal is likely to re.ect a spatial average of the activity of neurons with partly dissimilar response properties, its interpretation in terms of neuronal information processing may be di/cult. We explored this problem by means of a simple computational model based on known tuning properties of individual neurons and on the assumption that...

To model the percentage change of blood oxygenation leveldependent (BOLD) signal and reaction time in a dual task, we propose a new mathematical modeling approach—a queuing network approach based on queuing network theory of human performance (Liu, 1996, 1997) and current discoveries in neuroimage studies. This approach includes a queuing network architecture representing the information proces...

Steven Dakin and colleagues present a detailed analysis of the stimuli used in our study [1] revealing that our method of interpolation is associated with certain changes in the statistical properties of interpolated images. They argue that these changes might represent a possible source of the BOLD signal non-monotonicity that we observed in the primary visual cortex (V1). This finding is inte...

BACKGROUND AND PURPOSE Blood oxygenation level-dependent (BOLD) functional MRI (fMRI) is a promising method for defining brain recovery after stroke quantitatively. Applications thus far have assumed that the BOLD hemodynamic response in patients after stroke is identical to that in healthy controls. However, because of local vascular compromise or more diffuse vascular disease predisposing to ...

In humans, theta band (5-7 Hz) power typically increases when performing cognitively demanding working memory (WM) tasks, and simultaneous EEG-fMRI recordings have revealed an inverse relationship between theta power and the BOLD (blood oxygen level dependent) signal in the default mode network during WM. However, synchronization also plays a fundamental role in cognitive processing, and the le...

In most functional magnetic resonance imaging (fMRI) studies, brain activity is localized by observing changes in the blood oxygenation level-dependent (BOLD) signal that are believed to arise from capillaries, venules and veins in and around the active neuronal population. However, the contribution from veins can be relatively far downstream from active neurons, thereby limiting the ability of...

BACKGROUND AND PURPOSE Changes in the blood-oxygen-level-dependent (BOLD) signal provide a noninvasive measure of blood flow, but a detailed comparison with established perfusion parameters in acute stroke is lacking. We investigated the relationship between BOLD signal temporal delay and dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) in stroke patients. METHODS In 30 pa...

OBJECTIVE The aim of this study was to investigate whether the blood oxygenation level-dependent (BOLD) contrast magnetic resonance imaging (MRI) can evaluate tumor maturity and preoperatively differentiate prostate cancer (PCa) from benign prostate hyperplasia (BPH). PATIENTS AND METHODS BOLD MRI based on transverse relaxation time*-weighted echo planar imaging was performed to assess PCa (1...

Electrophysiology studies routinely investigate the relationship between neural oscillations and task performance. However, the sluggish nature of the BOLD response means that few researchers have investigated the spectral properties of the BOLD signal in a similar manner. For the first time we have applied group ICA to fMRI data collected during a standard working memory task (delayed match-to...

Steven Dakin and colleagues present a detailed analysis of the stimuli used in our study [1] revealing that our method of interpolation is associated with certain changes in the statistical properties of interpolated images. They argue that these changes might represent a possible source of the BOLD signal non-monotonicity that we observed in the primary visual cortex (V1). This finding is inte...