Neglect of radial and vertical space: importance of the retinotopic reference frame.

Neglect from bilateral brain injury can disrupt responses along space defined by the vertical and radial axes. The spatial reference frames for vertical and radial neglect remain largely undefined, however. The viewer centred system, for example, consists of retinocentric and cephalocentric/corporacentric frames. In the present study, different viewer centred reference frames were dissociated in a patient with combined far radial superior vertical neglect through performance of radial line bisections above and below eye level. To separate reference frames for vertical space, bisections were performed while the patient was lying sideways. Results suggest that this patient's neglect respected a retinotopic viewer centred reference frame.