A new paradigm to investigate the roles of head and eye movements in the coordination of whole-body movements

Although previous studies have demonstrated the existence of coordinated eye and head movements during gaze shifts, none has studied the temporal and spatial characteristics of the various body segments during gaze transfers that require whole body movements. Without this information it is not possible to determine the extent of the interaction between the oculomotor control system and the motor control systems responsible for moving other body parts. Presented here is a detailed analysis of the timing and kinematic characteristics of participants (N=5) eye, head, upper body and feet during rotation of their body to align with light cues positioned at eccentric locations (45, 90, and 135°, left and right of centre). For all rotation amplitudes there was a clear sequence of body segment orientation (eye, head, upper body and feet) consistent with previous studies of locomotor steering and significant correlations between the onset latency times of the eyes and all body segments. There were also significant correlations between temporally aligned kinematic profiles of the feet and the eye in space for all movement amplitudes. The extent of correlation was significantly lower for displacement profiles of the feet versus head and of the feet versus upper body. These findings demonstrate substantial eye-foot coordination during a novel whole-body rotation paradigm and provide evidence that the output of the motor systems responsible for moving the feet is heavily influenced by the motor systems responsible for generating and coordinating eye and head movements to peripheral targets.