Table 1.

Correlation of the two eyes during optokinesis under different stimulus conditions

ButterflyfishPipefishSandlance
Normal optokinesisYoked fast phaseMainly independent fast phaseIndependent fast phase
Split drum stimulationDisjunctive fast and slow phase, slow phase gain linked, convergence to temporo-nasal stimulationIndependent fast and slow phase, independent slow phase gainIndependent fast and slow phase, independent slow phase gain
Monocular stimulation with visual feedback to contralateral eyeYoked optokinesis, seeing eye drives eye that views stationary gratingIndependent slow phase, fast eye movement sometimes linked, but no optokinesis in contralateral eyeIndependent slow and fast phase, no optokinesis in contralateral eye
Monocular stimulation, contralateral eye occludedYoked optokinesis, seeing eye drives occluded eyeYoked slow phase, fast phase largely independentIndependent slow and fast phase, no optokinesis in contralateral eye
  • The results clearly show differences in the degree of correlation between the two eyes in the species studied. The emerging picture is that of a sliding scale of conjugacy, revealing different linkage strengths between the eyes of the different species.