Interactions between short-term vertical phoria adaptation and nonconjugate adaptation of vertical pursuits.

We have demonstrated that short-term vertical position-specific phoria adaptation contributes to nonconjugate adaptation of vertical pursuits, but not to nonconjugate adaptation of vertical saccades. Binocular adaptation to multiple stationary vertical disparities resulted in both nonconjugate pursuits and phoria aftereffects but had little effect on the early step component of vertical saccades. Similarly, binocular nonconjugate adaptation of vertical pursuits produced both nonconjugate pursuits and fixation phoria aftereffects. Position-specific adaptation of nonconjugate pursuit was demonstrated by adapting to disparate motion in the upper field which resulted in nonconjugate pursuit aftereffects that were greater in the upper than the lower hemifield. These nonconjugate pursuits were accompanied by position-specific phoria aftereffects, indicating that common mechanisms underlie adaptation of vertical phoria and nonconjugate pursuits.