ABSTRACT
A rudimentary appreciation of three-dimensional (3D) kinematics is particularly important for clinicians who want to understand the neural underpinnings of movement deficits in real 3D space. A similar range has been observed in human head positions, and also in the orientation of various segments of the arm during various visually guided behaviours. A large range of torsional, vertical, and horizontal angular velocities were produced by inducing primates to generate horizontal and vertical saccades while rotating the head torsionally, which induced torsional components in the quick phases. Since the torsional and horizontal axes of the Fick-like coordinate system for head control remain fixed in the head, and the Listing’s plane-based coordinates for eye movements are entirely fixed with respect to the head, these coordinates remain in register. For example, apertures in head-fixed goggles can be used to drastically restrict the visual range relative to the head, without constraining the head.
