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Current understanding of blood oxygenation level dependent (BOLD) fMRI physiology predicts a close relationship between BOLD signal and blood hematocrit level. However, neither this relationship nor its effect on BOLD percent activation (BPA) has been empirically examined in man. To that end, BPA in primary visual cortex in response to photic stimulation(More)
A rapid, in-plane image registration algorithm that accurately estimates and corrects for rotational and translational motion is described. This automated, one-pass method achieves its computational efficiency by decoupling the estimation of rotation and translation, allowing the application of rapid cross-correlation and cross-spectrum techniques for the(More)
Attentional bias for drug-related stimuli, as measured by emotional Stroop (ES) tasks, is predictive of treatment outcomes for tobacco smoking and other abused drugs. Characterizing relationships between smoking-related attentional bias and brain reactivity to smoking images may help in identifying neural substrates critical to relapse vulnerability. To(More)
A novel, two-dimensional, J-resolved chemical-shift imaging sequence was used to collect gamma-aminobutyric acid (GABA) spectroscopic imaging data on six healthy subjects at 4 T. Using image segmentation and a linear-regression analysis relating brain GABA level to tissue-type, a consistent and significant (n = 6, p < 0.01) elevation of mean GABA levels was(More)
BACKGROUND Proton magnetic resonance spectroscopy was used to determine the effects of intravenous cocaine or placebo administration on human basal ganglia water and metabolite resonances. METHODS Long echo time, proton magnetic resonance spectra of water and intracellular metabolites were continuously acquired from an 8-cm(3) voxel centered on the left(More)
A proton MR spectral editing technique employing a spatially localized, double-quantum filter (DQF) was used to measure gamma-aminobutyric acid (GABA) in the human brain at 1.5 T. The double-quantum method provided robust, single-shot suppression of uncoupled resonances from choline, creatine, and NAA and allowed detection of the gamma CH2 GABA (3.0 ppm)(More)
BACKGROUND Brain dysfunction in prefrontal cortex (PFC) and dorsal striatum (DS) contributes to habitual drug use. These regions are constituents of brain networks thought to be involved in drug addiction. To investigate whether networks containing these regions differ between nicotine dependent female smokers and age-matched female non-smokers, we employed(More)
PURPOSE Prior proton magnetic resonance spectroscopy (MRS) studies have consistently reported decreased brain n-acetyl aspartate (NAA) levels and increased myo-inositol (mI) levels in subjects with Alzheimer's disease (AD) relative to healthy comparison subjects. These studies have usually been conducted in small and homogeneous populations of patients with(More)
OBJECTIVE Studies of depressed adults have shown abnormalities in cerebral energy metabolism, as noted by low brain levels of nucleoside triphosphate (NTP), which primarily represents adenosine triphosphate (ATP). This study was undertaken to determine whether proton magnetic resonance spectroscopy (1H MRS) measures of the low-field purine resonance, which(More)
OBJECTIVES Alterations in choline and myo-inositol metabolism have been noted in bipolar disorder, and the therapeutic efficacy of lithium in mania may be related to these effects. We wished to determine the relationship between anterior cingulate cortex choline and myo-inositol levels, assessed using proton magnetic resonance spectroscopic imaging (MRSI),(More)