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Responses of rostral frontal and retrosplenial cortices to the emotional significance of words were measured using functional magnetic resonance imaging (fMRI). Twenty-six strongly right-handed participants engaged in a language task that alternated between silent word generation to categories with positive, negative, or neutral emotional connotation and a(More)
Two patients with residual nonfluent aphasia after ischemic stroke received an intention treatment that was designed to shift intention and language production mechanisms from the frontal lobe of the damaged left hemisphere to the right frontal lobe. Consistent with experimental hypotheses, the first patient showed improvement on the intention treatment but(More)
fMRI was used to determine the frontal, basal ganglia, and thalamic structures engaged by three facets of language generation: lexical status of generated items, the use of semantic vs. phonological information during language generation, and rate of generation. During fMRI, 21 neurologically normal subjects performed four tasks: generation of nonsense(More)
Hemodynamic responses to auditory and visual stimuli and motor tasks were assessed for the nonlinearity of response in each of the respective primary cortices. Five stimulus or task durations were used (1, 2, 4, 8, and 16 s), and five male subjects (aged 19 +/- 1.9 years) were imaged. Two tests of linearity were conducted. The first test consisted of using(More)
Functional MRI (fMRI) studies of jaw motion, speech, and swallowing disorders have been hampered by motion artifacts. Tissue motion perturbs the static magnetic field, creating geometric distortions in echo-planar images that lead to many false positives in activation maps. These problems have restricted blood oxygenation level-dependent (BOLD) fMRI studies(More)
Mapping the functional response of the somatosensory cortex is useful both for characterizing normal brain activity and for determining the functional integrity of damaged cortex compromised by stroke or other neurological insults. A variety of stimulators have been used to produce somatosensory cortex activation in functional brain imaging, including(More)
Functional MRI (fMRI) studies of tasks involving orofacial motion, such as speech, are prone to problems related to motion-induced magnetic field variations. Orofacial motion perturbs the static magnetic field, leading to signal changes that correlate with the task and corrupt activation maps with false positives or signal loss. These motion-induced signal(More)
Two patients (G01, J02) with chronic nonfluent aphasia and sentence production deficits received syntactic mapping treatment to improve sentence production. The patients had dramatically different outcomes in that improved syntax production generalized to nontreatment tasks for G01, but not for JO2. To learn how treatment influenced the neural substrates(More)
Cerebral blood volume functional magnetic resonance imaging (CBV-fMRI) experiments employing iron oxide contrast agent were conducted in rat whisker barrel cortex at 3 Tesla. Stimuli of constant frequency (12 Hz) but variable duration and intensity were delivered separately using a homemade whisker stimulator. The temporal behavior of CBV-fMRI signals was(More)
It is hypothesized that, based upon partial volume effects and spatial non-uniformities of the scanning environment, repositioning a subject's head inside the head coil between separate functional MRI scans will reduce the reproducibility of fMRI activation compared to a series of functional runs where the subject's head remains in the same position. Nine(More)