抄録
The smooth pursuit system moves the eyes in space accurately to track slowly moving objects of interest while compensating for visual inputs from the moving background. In daily life, smooth-pursuit is performed by coordination of eye and head movements (i.e. gaze-pursuit). To examine the effects of visual background and contribution of head movement in head-free pursuit, in this study we examined smooth gaze pursuit in a young Japanese monkey that was trained to pursue a target moving on the vertical screen at 0.5Hz (±20°). Eye and head movements were recorded by the search coil method. Body movements were restrained and care was taken to minimize the weights of head holder during head-free pursuit. Eye-, head- and gaze- (eye+head) gains (re target velocity) were calculated in head restrained and free conditions with or without a random dot visual background. In head-free pursuit, vertical gaze velocity gains with and without a background were 0.75-0.90 and 0.86-0.97, respectively. Head velocity gains were 0.24-0.44 and were similar with or without a background. Upward gaze velocity was significant lower than downward. Eye velocity gains ranged from 0.41 to 0.65. Upward eye velocity gains were significantly lower than downward in both head-free and restrained conditions. Eye velocity in head-free pursuit led target velocity by the mean of 14°, whereas head velocity lagged target velocity by the mean of 34°. No asymmetry was observed in leftward and rightward pursuit with a background. [Jpn J Physiol 54 Suppl:S181 (2004)]
