Journal ArticleDOI
Automated shimming at 1.5 T using echo-planar image frequency maps.
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TLDR
This work developed an automated image‐based procedure to shim the static (B0) field using the rapid acquisition capability of echo‐planar Imaging to collect the required frequency data rapidly, rendering the shim data acquisition time negligible in comparison with the total study time.Abstract:
Using echo-planar imaging, we developed an automated image-based procedure to shim the static (B0) field. Our method uses the rapid acquisition capability of echo-planar imaging to collect the required frequency data rapidly, rendering the shim data acquisition time negligible in comparison with the total study time. We address image distortion issues involved in echo-planar imaging acquisition of the data and formulate analytic methods for arriving at an optimal shim for the NMR imaging experiment in a single iteration. We investigated the use of cost functions other than least-squares (Chebychev, high-order numeric) and found that choice between the cost functions we tested was irrelevant to resultant image quality, at least when used in conjunction with low-order shims. With appropriate integration, the method has become routine practice for investigators at our laboratory.read more
Citations
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Journal ArticleDOI
Masked Presentations of Emotional Facial Expressions Modulate Amygdala Activity without Explicit Knowledge
Paul J. Whalen,Scott L. Rauch,Nancy L. Etcoff,Sean C. McInerney,Michael B. Lee,Michael A. Jenike +5 more
TL;DR: This study, using fMRI in conjunction with masked stimulus presentations, represents an initial step toward determining the role of the amygdala in nonconscious processing.
Journal ArticleDOI
Response and Habituation of the Human Amygdala during Visual Processing of Facial Expression
Hans C. Breiter,Nancy L. Etcoff,Paul J. Whalen,William A Kennedy,Scott L. Rauch,Randy L. Buckner,Monica M. Strauss,Steven E. Hyman,Bruce R. Rosen +8 more
TL;DR: The human amygdala responds preferentially to emotionally valenced faces and rapidly habituates to them and is counterbalanced to happy versus neutral faces, suggesting a possible generalized response to emotions valenced stimuli.
Journal ArticleDOI
Dynamic Statistical Parametric Mapping: Combining fMRI and MEG for High-Resolution Imaging of Cortical Activity
Anders M. Dale,Arthur K. Liu,Bruce Fischl,Randy L. Buckner,John W. Belliveau,Jeffrey D. Lewine,Eric Halgren,Eric Halgren,Eric Halgren +8 more
TL;DR: A technique that combines structural and functional MRI with magnetoencephalography (MEG) to obtain spatiotemporal maps of human brain activity with millisecond temporal resolution was used to obtain dynamic statistical parametric maps of cortical activity during semantic processing of visually presented words.
Journal ArticleDOI
Acute effects of cocaine on human brain activity and emotion
Hans C. Breiter,Randy L. Gollub,Robert M. Weisskoff,David N. Kennedy,Nikos Makris,Joshua D. Berke,Julie M. Goodman,Howard L. Kantor,David R. Gastfriend,J. Riorden,R. Thomas Mathew,Bruce R. Rosen,Steven E. Hyman +12 more
TL;DR: The ability of fMRI to map dynamic patterns of brain activation following cocaine infusion in cocaine-dependent subjects is demonstrated and evidence of dynamically changing brain networks associated with cocaine- induced euphoria and cocaine-induced craving is provided.
Journal ArticleDOI
Exaggerated amygdala response to masked facial stimuli in posttraumatic stress disorder: a functional MRI study.
Scott L. Rauch,Paul J. Whalen,Lisa M. Shin,Lisa M. Shin,Sean C. McInerney,Michael L. Macklin,Natasha B. Lasko,Scott P. Orr,Roger K. Pitman +8 more
TL;DR: This work provides the first evidence for exaggerated amygdala responses to general negative stimuli in PTSD by using a probe that emphasizes automaticity and provides initial evidence of amygdala hyperresponsivity dissociated from the "top-down" influences of medial frontal cortex.
References
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Journal ArticleDOI
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Journal ArticleDOI
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Journal ArticleDOI
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TL;DR: Results indicate that AUTOSHIM improves the overall homogeneity; however, local high‐order field distortions which cannot be corrected by linear gradients are generated by certain air/tissues and bone/tissue morphology and a “ZOOM SHIM” may be applied over a limited region of interest for local homogeneity improvement at the expense of other regions.
Journal ArticleDOI
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