Hemisphere asymmetry for eye gaze mechanisms.

To investigate left/right asymmetries in cerebral gaze mechanisms, eye deviation was evaluated in 90 patients following intracarotid sodium amylobarbitone injections. For right-handed subjects with left cerebral language dominance, the occurrence and severity of eye deviation were greater for right versus left hemisphere injections. In contrast, subjects with mixed cerebral dominance for language/handedness exhibited no left/right difference in the incidence of eye deviation. The results are consistent with right cerebral dominance for attentional/intentional mechanisms directed at external space. Further analysis suggests that the cerebral asymmetry for gaze may be due to an evolutionary loss of attentional/intentional mechanisms by the left cerebral hemisphere as language function developed.