Prediction in a biomimetic controller for binocular target pursuit on a free head
Wei-Jen Jessica Lee · eScholarship@McGill (McGill) · 2004
Physiological evidence suggests that a single symmetric controller in the brainstem is involved in the oculomotor system (OCS) for all types of eye movements. Focusing on ocular tracking with slow pursuit (slow phase) and saccades (fast phase), a previously developed bilateral controller by Galiana is the first to adopt this unified philosophy which allows it to be free of instability during switching between modes. We upgrade this model by incorporating additional sensory signals observed in nature. 1. During slow phases, retinal slip from the flocculus and temporal integration via superior colliculi compensate for large visual delays and provide near perfect ramp tracking. 2. For fast phase control, the saccade goal, which initially only considers retinal discrepancy, now also corrects for the disparity caused by non-zero retinal slip values during saccades. The resulting OCS achieves both slow phase velocity tracking and fast phase position matching better than its precursor, coordinating two eyes on a moving head in two dimensions.