Hemisphere Asymmetry for Eye Gaze Mechanisms

Abstract

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.

Hemispheric asymmetry of gaze deviation and relationship to neglect in acute stroke

“…In one study, investigators employing the intracarotid sodium amobarbital test demonstrated that ipsilateral GD was more common after right-hemisphere rather than left-hemisphere anesthesia in 70 righthanded/left-hemisphere language-dominant epilepsy patients. 4 In this study, no such asymmetry was seen in 20 patients considered to have mixed cerebral dominance. Using the stroke database from the Trial of Org 10172 in Acute Stroke Treatment (TOAST), we hoped to delineate the anatomy of conjugate GD and to determine its relationship to hemispatial neglect and handedness.…”

“…3 Ipsilateral conjugate gaze deviation (GD) resulting from unilateral brain damage has also been reported to occur more frequently with RHLs than with LHLs. [4][5][6][7] In a study of 120 stroke patients, 5 GD was found to be more common, more severe, and more persistent with RHLs.…”

An assessment of hemineglect in children with attention‐deficit hyperactivity disorder

“…According to the attentional model of Kinsbourne (1987), the somewhat compromised right hemisphere of these patients would be unable to restrain a shift of attentional bias toward the right space created by the verbal nature of the task activating the left hemisphere. In addition, a right-hemisphere deficit might have affected the freedom with which gaze is turned across the midline to the left (Meador et al, 1989). Alternatively, and not necessarily in conflict with the above suggestion, any verbal test might remind the pupil of regular classroom problems that could conceivably trigger anxiety in a deficient child.…”

TMS over the Left Posterior Parietal Cortex Prolongs Latency of Contralateral Saccades and Convergence

“…11 These findings are again in agreement with the study of patients. 7 Certain specialization of the right hemisphere, and more precisely of the right parietal lobe has been found for certain functions, such as visuospatial function, 24,25 the control of eye deviation, 26 reflexive visually guided saccades, and memory-guided saccades. 7,27 The right PPC according to these investigators would be involved in the process of fixation disengagement, which is necessary for any eye movements to occur.…”