Human eye-head coordination in two dimensions under different sensorimotor conditions

摘要: The coordination between eye and head movements during a rapid orienting gaze shift has been investigated mainly when subjects made horizontal towards visual targets with the eyes starting at centre of orbit. Under these conditions, it is difficult to identify signals driving two motor systems, because their initial errors are identical equal coordinates sensory stimulus (i.e. retinal error). In this paper, we investigate head-free saccades human as well auditory stimuli presented in two-dimensional frontal plane, under both aligned unaligned fixation conditions. Although basic patterns for were qualitatively comparable modalities, systematic differences also obtained suggesting task-dependent movement strategy. Auditory-evoked shifts endowed smaller eye-head latency differences, consistently larger concomitant ocular than visually triggered movements. By testing control eccentric positions, found that displacement vector was best related motor-error (target-re-head), rather error (target-re-eye), regardless target modality. These findings suggest an independent systems by commands different frames reference. However, observed influence oculomotor response on properties evoked movements, indicating subtle coupling systems. results discussed view current models.