Line bisection in the split brain.
The authors examined line bisection in 4 patients with resection of the corpus callosum and in 22 control participants. The control participants showed a leftward bias, especially with the left hand, implying right-hemispheric dominance in spatial attention. Two patients with anterior callosotomy showed similar biases, suggesting that the anterior callosum plays only a small role. A patient with complete callosotomy showed a strong right bias, regardless of hand use. A patient with posterior callosotomy showed the opposite pattern: a strong left bias, regardless of hand use. These data suggest that the posterior corpus callosum normally plays a role in line bisection and that the resection of the posterior corpus callosum produces consistent bias. The direction of the bias depends on which hemisphere assumes control.
Department of Psychology, University of Auckland, Auckland, New Zealand. markus.hausmann@ruhr-uni-bochum.de
Markus
M
Hausmann
Michael C
MC
Corballis
Mara
M
Farbi
D000328:Adult; D003337:Corpus Callosum / Q000502:physiology*; D004827:Epilepsy / Q000601:surgery; D005556:Form Perception / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D019635:Neurosurgical Procedures; D012727:Sex Characteristics; D014794:Visual Fields / Q000502:physiology