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In previous research (D. J. Bryant, B. Tversky, & N. Franklin, 1992; N. Franklin & B. Tversky, 1990), the authors showed that spatial knowledge conveyed by descriptions and direct experience induces participants to take the perspective of a character surrounded by objects. In this study, the authors used models and diagrams to convey the same information.(More)
This work is dedicated to all the wonderful teachers who have shaped my life and intellect. Most of the CPU time for the experiments was made possible by NSF grant EIA-0303609, for the Mastodon cluster at UT-Austin. I would like to thank my friends and colleagues in the UTCS Neural Networks Research Group, the members of my committee, and the many wonderful(More)
Fluid attenuated inversion recovery pulse sequences with a long echo time (TE) have been used to image the brain in one volunteer and four patients. The long inversion time used with this sequence suppresses the signal from CSF and the long TE produces very heavy T2 weighting. The marked reduction in flow artefact from CSF and the high T2 weighting enabled(More)
The gene responsible for Huntington's disease (HD) has been located, but its action and the pathophysiology of HD remain unclear. Glutamate excitotoxicity may contribute to the striatal neurodegeneration seen in HD. We used localised proton magnetic resonance spectroscopy (MRS) of the brain to investigate five patients with early HD, one symptom-free gene(More)
The purpose of this study was to correlate the hyperintensity in the globus pallidus seen on T1-weighted magnetic resonance imaging (MRI) of the brain in chronic liver disease with changes in metabolite ratios measured from both proton and phosphorus-31 magnetic resonance spectroscopy (MRS) localised to the basal ganglia. T1-weighted spin echo (T1WSE)(More)
All users of NMR equipment are familiar with the desirability of achieving as high a quality of field as possible. On the other hand, it is easy to forget that the field quality of relevance in both imaging and spectroscopy is that over individual voxels, and not the whole volume. This note demonstrates in practice how performance in poor fields is improved(More)
Proton magnetic resonance spectroscopy was used to examine, within the first month of life, the brains of 11 infants born at term--10 with signs of hypoxic-ischaemic encephalopathy (HIE) and one who was neurologically normal at birth. All the infants had peak resonances on their spectra which could be assigned to N-acetyl-aspartase (NAA), choline-containing(More)
Regional variations in proton magnetic resonance spectroscopy (MRS) were assessed in 26 patients and 14 healthy volunteers using a two dimensional chemical shift imaging technique. Patients were classified as being neuropsychiatrically unimpaired, or as having subclinical or overt chronic hepatic encephalopathy (CHE). Peak area ratios of choline (Cho),(More)
Four experiments investigated the use of cognitive strategies for encoding spatial location in visual figures. Subjects reproduced the position of a dot in a square figure that had distance markers placed along two sides. Subjects' responses were biased toward imaginary points of intersection formed by the distance markers when subjects responded from(More)