Potential and optimal target fixating control of the human head/eye complex

The human head and eye rotate in coordination to rapidly project images of stationary targets from the visual space. Once a target is fixated, the head/eye complex maintains stability of the image, even while the head continues to move toward the target. The orientation of the head is constrained by Donders' law, whereas the final orientation of the eye satisfies Listing's constraint with respect to the final orientation of the head. The eye is rotated opposite to the movement of the head to compensate and maintain image stability. Using dynamic modeling, this brief investigates the underlying target fixating control mechanisms behind the head and eye movements. Finally, model output trajectories of the head and eye are compared with the corresponding experimentally observed trajectories.