28 research outputs found
The wind catcher : a passive cooling device for hot arid climate
BACKGROUND: fMRI is becoming a standard tool for the presurgical lateralization and mapping of brain areas involved in language processing. However, its within-subject reproducibility has yet to be fully explored. OBJECTIVE: To evaluate within-test and test-retest reliability of language fMRI in consecutive patients undergoing evaluation for epilepsy surgery. METHODS: Thirty-four unselected patients were investigated once (within-test reliability) and 12 patients twice (test-retest reliability). The imaging series consisted of an alternating 25-second synonym judgment condition with a 25-second letter-matching condition repeated 15 times. Reproducibility of activation maps of the first and second half of session 1 or activation maps of sessions 1 and 2 was evaluated by comparing one global and three regional lateralization indexes (Broca's area, remaining prefrontal cortex, temporoparietal area) and on a voxel-by-voxel basis (intraclass correlation coefficient, percentage overlap, correlation of t-values). RESULTS: Global and regional language lateralization was achieved with high reliability within and across sessions. Reproducibility was evenly distributed across both hemispheres but not within each hemisphere. Frontal activations were more reliable than temporoparietal ones. Depending on the statistical threshold chosen, the voxel-by-voxel analysis revealed a mean overlap of activations derived from the first and second investigation of up to 48.9%. CONCLUSION: Language fMRI proved sufficiently reliable for the determination of global and regional lateralization of language representation in individual unselected patients with epilepsy
Process dissociation between contextual retrieval and item recognition
We employed a source memory task in an event related fMRI study to dissociate MTL processes associated with either contextual retrieval or item recognition. To introduce context during study, stimuli (photographs of buildings and natural landscapes) were transformed into one of four single-color-scales: red, blue, yellow, or green. In the subsequent old/new recognition memory test, all stimuli were presented as gray scale photographs, and old-responses were followed by a four-alternative source judgment referring to the color in which the stimulus was presented during study. Our results suggest a clear-cut process dissociation within the human MTL. While an activity increase accompanies successful retrieval of contextual information, an activity decrease provides a familiarity signal that is sufficient for successful item recognition. © 2004 Lippincott Williams & Wilkins
Process dissociation between contextual retrieval and item recognition.
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Process dissociation between contextual retrieval and item recognition
We employed a source memory task in an event related fMRI study to dissociate MTL processes associated with either contextual retrieval or item recognition. To introduce context during study, stimuli (photographs of buildings and natural landscapes) were transformed into one of four single-color-scales: red, blue, yellow, or green. In the subsequent old/new recognition memory test, all stimuli were presented as gray scale photographs, and old-responses were followed by a four-alternative source judgment referring to the color in which the stimulus was presented during study. Our results suggest a clear-cut process dissociation within the human MTL. While an activity increase accompanies successful retrieval of contextual information, an activity decrease provides a familiarity signal that is sufficient for successful item recognition. © 2004 Lippincott Williams & Wilkins
Intrasubject reproducibility of presurgical language lateralization and mapping using fMRI
Background: fMRI is becoming a standard tool for the presurgical lateralization and mapping of brain areas involved in language processing. However, its within-subject reproducibility has yet to be fully explored. Objective: To evaluate within-test and test-retest reliability of language fMRI in consecutive patients undergoing evaluation for epilepsy surgery. Methods: Thirty-four unselected patients were investigated once (within-test reliability) and 12 patients twice (test-retest reliability). The imaging series consisted of an alternating 25-second synonym judgment condition with a 25-second letter-matching condition repeated 15 times. Reproducibility of activation maps of the first and second half of session 1 or activation maps of sessions 1 and 2 was evaluated by comparing one global and three regional lateralization indexes (Broca's area, remaining prefrontal cortex, temporoparietal area) and on a voxel-by-voxel basis (intraclass correlation coefficient, percentage overlap, correlation of t-values). Results: Global and regional language lateralization was achieved with high reliability within and across sessions. Reproducibility was evenly distributed across both hemispheres but not within each hemisphere. Frontal activations were more reliable than temporoparietal ones. Depending on the statistical threshold chosen, the voxel-by-voxel analysis revealed a mean overlap of activations derived from the first and second investigation of up to 48.9%. Conclusion: Language fMRI proved sufficiently reliable for the determination of global and regional lateralization of language representation in individual unselected patients with epilepsy
Nitazoxanide in the treatment of Ascaris lumbricoides in a rural zone of Colima, Mexico
Functionalized carbene ligands: Increasing the steric bulk of R1 on 1 from H to tBu results in lengthening of the M-N bond (by up to 9 %), lowered activation energy for chelate opening (cf. 2) by 17 kcal mol -1, and improved binding of an amine and intramolecular hydrogen bonding (3). Iridium species with R1=tBu are effective catalysts of base-free intramolecular hydroamination, unlike less-hindered analogues. Copyright " 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.",,,,,,"10.1002/chem.201100521",,,"http://hdl.handle.net/20.500.12104/41220","http://www.scopus.com/inward/record.url?eid=2-s2.0-79957957253&partnerID=40&md5=e5f420da903f48ac5c6ea8173f95b40d",,,,,,"24",,"Chemistry - A European Journal",,"660