SCHEMATIC MODEL OF SACCADE-VERGENCE INTERACTIONS

The purpose of this study was to determine whether saccadic disconjuga cy under the disparity-only condition consistently facilitates the ver gence response, and to develop a schematic model of saccade-vergence c ontrol to account for the present as well as previous results. Vertica l line targets on two oscilloscope screens were presented dichopticall y to the eyes using horizontal step displacements of various amplitude s. Binocular horizontal eye movements were recorded using the infrared reflection technique in five normal subjects. The experimental result s showed an approximately equal distribution of facilitation and disfa cilitation by the disconjugate saccades. This indicated that with disp arity-only stimulation, in the absence of absolute depth and blur cues , there was no consistent enhancement of the vergence response. The sc hematic model showed that sequential and simultaneous onset of the dis junctive and conjugate controller signals resulted in non-facilitation and facilitation, respectively, of the ongoing movement. Thus, the mo del was able to account for the present results under the disparity-on ly condition as well as previous results under the rich-stimulus-cues condition.