Imagery in a commissurotomized patient.
A commissurotomized patient, L.B., was tested on several imagery tasks, in which the stimuli were flashed tachistoscopically in the left or right visual half-field. On tests requiring the generation of images of lowercase letters from their uppercase versions, or the generation of the positions of the hands on a clockface from digitally presented times, there was a strong right half-field (left-hemispheric) advantage in accuracy, but a left half-field (right-hemispheric) advantage in reaction time (RT). On tests requiring the mental rotation of letters or stickfigures to the upright, however, there was a strong left half-field (right-hemispheric) advantage in accuracy, RT, and conformity of RTs to an ideal "mental-rotation" function when plotted against angular orientation. These data provide strong evidence that the right hemisphere was capable of mental rotation comparable to that of normal subjects; the left hemisphere, by contrast, seemed virtually incapable of mental rotation in the early testing sessions, and never achieved the proficiency of the right.
Corballis
M C
MC
University of Auckland, New Zealand.
Sergent
J
J
D000328:Adult; D002540:Cerebral Cortex / Q000503:physiopathology; D003337:Corpus Callosum / Q000503:physiopathology*; D004193:Discrimination Learning / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology*; D004411:Dyslexia, Acquired / Q000503:physiopathology; D004827:Epilepsy / Q000601:surgery*; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D009949:Orientation / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011183:Postoperative Complications / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012660:Semantics