نتایج جستجو برای: blood oxygen level dependent bold

تعداد نتایج: 2405743  

2008
Bernard Ng Rafeef Abugharbieh Martin J. McKeown

In conventional functional magnetic resonance imaging (fMRI) analysis, activation is often inferred by examining only the intensity modulation of blood-oxygen-level dependent (BOLD) signal of each voxel in isolation or in small, local clusters. However, as has been recently demonstrated, activation can in fact be detected by examining the spatial modulation of the BOLD distribution within a reg...

Journal: :Neuroreport 2003
Kevin A Pelphrey Peter B Mack Allen Song Güven Güzeldere Gregory McCarthy

Using fMRI techniques sensitive to blood oxygen-level dependent (BOLD) contrast, we measured brain activity in participants (n=8) as they viewed images of faces presented periodically within a continuously changing montage of common objects. Consistent with prior studies, we identified regions of ventral extrastriate cortex, primarily in the fusiform and inferior temporal gyri and nearby cortex...

2000
Adam W. Anderson Rene Marois Eve R. Colson Bradley S. Peterson Charles C. Duncan Richard A. Ehrenkranz Karen C. Schneider John C. Gore Laura R. Ment

The objective of this study was to detect auditory cortical activation in non-sedated neonates employing functional magnetic resonance imaging (fMRI). Using echo-planar functional brain imaging, subjects were presented with a frequency-modulated pure tone; the BOLD signal response was mapped in 5 mm-thick slices running parallel to the superior temporal gyrus. Twenty healthy neonates (13 term, ...

Journal: :Journal of neurophysiology 2014
A Mitra A Z Snyder C D Hacker M E Raichle

The discovery that spontaneous fluctuations in blood oxygen level-dependent (BOLD) signals contain information about the functional organization of the brain has caused a paradigm shift in neuroimaging. It is now well established that intrinsic brain activity is organized into spatially segregated resting-state networks (RSNs). Less is known regarding how spatially segregated networks are integ...

2004
Michael L. Lipton

Functional magnetic resonance imaging (fMRI) is a technique that exploits magnetic resonance imaging (MRI) to detect regional brain activity through measurement of the hemodynamic response that is coupled to electrical neuronal activity. The most common fMRI method detects blood oxygen level dependent (BOLD) contrast. The BOLD effect represents alteration in the ratio of deoxygenated to oxygena...

Journal: :Journal of physics 2023

Abstract Blood Oxygen Level Dependent ( BOLD ) fMRI is widely used for non-invasive brain mapping and neuroimaging. Despite the challenges, significant advancements have been made in empirically explaining several signal features. Before applying functional connectivity measures to assess signal, preprocessing required. Different stimuli produced by a regular periodic oscillation pulse propagat...

Journal: :NeuroImage 2006
Yashar Behzadi Thomas T Liu

Localized changes in oxygen consumption related to increased neural activity can result in a small and transient "initial dip" of the blood oxygenation level-dependent (BOLD) signal used in functional magnetic resonance imaging (fMRI). The initial dip has been of great interest to the fMRI community because it may provide a more accurate and localized measure of neural activity than the convent...

Journal: :The Journal of neuroscience : the official journal of the Society for Neuroscience 2009
George I Christopoulos Philippe N Tobler Peter Bossaerts Raymond J Dolan Wolfram Schultz

Decision making under risk is central to human behavior. Economic decision theory suggests that value, risk, and risk aversion influence choice behavior. Although previous studies identified neural correlates of decision parameters, the contribution of these correlates to actual choices is unknown. In two different experiments, participants chose between risky and safe options. We identified di...

Journal: :The Journal of neuroscience : the official journal of the Society for Neuroscience 2008
James M Johnston S Neil Vaishnavi Matthew D Smyth Dongyang Zhang Biyu J He John M Zempel Joshua S Shimony Abraham Z Snyder Marcus E Raichle

Slow (<0.1 Hz), spontaneous fluctuations in the functional magnetic resonance imaging blood oxygen level-dependent (BOLD) signal have been shown to exhibit phase coherence within functionally related areas of the brain. Surprisingly, this phenomenon appears to transcend levels of consciousness. The genesis of coherent BOLD fluctuations remains to be fully explained. We present a resting state f...

Journal: :Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention 2007
Bernard Ng Rafeef Abugharbieh Samantha J. Palmer Martin J. McKeown

We present a new functional magnetic resonance imaging (fMRI) analysis method that incorporates both spatial and temporal dynamics of blood-oxygen-level dependent (BOLD) signals within a region of interest (ROI). 3D moment descriptors are used to characterize the spatial changes in BOLD signals over time. The method is tested on fMRI data collected from eight healthy subjects performing a bulb-...

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