Time course EPI of human brain function during task activation. Magn Reson Med
Using gradient-echo echo-planar MRI, a local signal increase of 4.3 +/- 0.3% is observed in the human brain during task activation, suggesting a local decrease in blood deoxyhemoglobin concentration and an increase in blood oxygenation. Images highlighting areas of signal enhancement temporally correlated to the task are created.
Available from: Benedikt A Poser
- "Since its discovery more than two decades ago (Bandettini et al., 1992; Kwong et al., 1992; Ogawa et al., 1992), non-invasive functional magnetic resonance imaging (fMRI) has evolved to become a primary method to study human brain function. The majority of fMRI experiments have been conducted using the blood oxygenation level dependent (BOLD) method (Ogawa et al., 1990), relying on T 2 * changes in gradient-echo based echo-planar imaging (GE-EPI, Mansfield, 1977) acquisitions. "
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ABSTRACT: Functional magnetic resonance imaging (fMRI) allows studying human brain function non-invasively up to the spatial resolution of cortical columns and layers. Most fMRI acquisitions rely on the blood oxygenation level dependent (BOLD) contrast employing T(*) 2 weighted 2D multi-slice echo-planar imaging (EPI). At ultra-high magnetic field (i.e., 7 T and above), it has been shown experimentally and by simulation, that T2 weighted acquisitions yield a signal that is spatially more specific to the site of neuronal activity at the cost of functional sensitivity. This study compared two T2 weighted imaging sequences, inner-volume 3D Gradient-and-Spin-Echo (3D-GRASE) and 2D Spin-Echo EPI (SE-EPI), with evaluation of their imaging point-spread function (PSF), functional specificity, and functional sensitivity at sub-millimeter resolution. Simulations and measurements of the imaging PSF revealed that the strongest anisotropic blurring in 3D-GRASE (along the second phase-encoding direction) was about 60% higher than the strongest anisotropic blurring in 2D SE-EPI (along the phase-encoding direction). In a visual paradigm, the BOLD sensitivity of 3D-GRASE was found to be superior due to its higher temporal signal-to-noise ratio (tSNR). High resolution cortical depth profiles suggested that the contrast mechanisms are similar between the two sequences, however, 2D SE-EPI had a higher surface bias owing to the higher T(*) 2 contribution of the longer in-plane EPI echo-train for full field of view compared to the reduced field of view of zoomed 3D-GRASE.
Frontiers in Neuroscience 05/2015; 9. DOI:10.3389/fnins.2015.00163 · 3.66 Impact Factor
Available from: Daniel Pach
- "Using fMRI, the blood oxygenation level dependent (BOLD) signal can localize brain regions modulated by sensory stimulation (Bandettini et al., 1992; Frahm et al., 1992; Kwong et al., 1992; Ogawa et al., 1992; Kurth et al., 2000; Ruben et al., 2001). "
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ABSTRACT: Acupuncture can be regarded as a complex somatosensory stimulation. Here, we evaluate whether the point locations chosen for a somatosensory stimulation with acupuncture needles differently change the brain activity in healthy volunteers. We used EEG, event-related fMRI, and resting-state functional connectivity fMRI to assess neural responses to standardized needle stimulation of the acupuncture point ST36 (lower leg) and two control point locations (CP1 same dermatome, CP2 different dermatome). Cerebral responses were expected to differ for stimulation in two different dermatomes (CP2 different from ST36 & CP1), or stimulation at the acupuncture point versus the control points. For EEG, mu rhythm power increased for ST36 compared to CP1 or CP2, but not when comparing the two control points. The fMRI analysis found more pronounced insula and S2 (secondary somatosensory cortex) activation, as well as precuneus deactivation during ST36 stimulation. The S2 seed-based functional connectivity analysis revealed increased connectivity to right precuneus for both comparisons, ST36 vs. CP1 and ST36 vs. CP2, however in different regions. Our results suggest that stimulation at acupuncture points may modulate somatosensory and saliency processing regions more readily than stimulation at non-acupuncture point locations. Also, our findings suggest potential modulation of pain perception due to acupuncture stimulation.
Frontiers in Human Neuroscience 02/2015; 9. DOI:10.3389/fnhum.2015.00074 · 3.63 Impact Factor
Available from: Wesley S. Randall
- "The advent of functional magnetic resonance imaging (fMRI) has shown an ability to map decision structures in the brain and provide a quantitative tool for neuroeconomic research (Bandettini et al., 1992; Ogawa et al., 1992). To date, fMRI has been applied to study a variety of neuronal processes such as primary sensory, motor cortices, cognitive functions, and decision making (Causse et al., 2013). "
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ABSTRACT: Purpose – The purpose of this paper is to describe the conversion of knowledge into value by examining the confluence of service-dominant logic (S-D logic), supply chain management (SCM), human resource management (HRM), and neuroeconomics. S-D logic suggests that knowledge is the raw material of value creation. SCM provides an organized foundation to study the conversion of raw materials into value. HRM recognizes the centrality of human decisions in the process of converting knowledge into value. Neuroscience gives insight into the efficiency and effectiveness of the human decisions processes. Global SCM provides more than markets and raw materials – global SCM provides the human resources central to value creation.
International Journal of Physical Distribution & Logistics Management 09/2014; 44(8):655-670. DOI:10.1108/IJPDLM-08-2013-0223 · 1.80 Impact Factor
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