Function of the dorsal neck muscles and tbeir afferent in put in Lateral gaze

为了研究腹侧颈部肌肉在横向视线移动中的作用，我们分析了单侧颈部剥离患者和正常受试者的眼睛和头部朝向视觉目标的运动。眼睛位置由眼电成像技术和头部位置由头盔上的电位器得到。当一个外围目标被点亮时，眼睛首先向它扫视，然后头部开始转向它。患者的视线转移与正常人一样准确。然而，与正常受试者相比，在患者中观察到头部位移的幅度减小和持续时间增加。因此，两组之间的眼动轨迹不同，特别是当目标在运动范围之外（超过50度）时。在患者中，凝视到达目标的时间明显更长，并且在头部运动时前庭眼反射几乎被抑制。此外，当目标灯熄灭后，受试者被要求继续保持对想象目标的注视方向时，患者表现出仅仅由于眼睛位置不稳定而使其注视逐渐偏离鼻腔方向的倾向，这可能反映了颈部肌肉向动眼中枢的适当传入信号的丢失。

To examine the role of the ventral neck muscles in lateral geze shift, the eye and head movements towards a visual target were analyzed in subjects with unilateral neck dissection and normal subjects. The eye position was derived by an electro-oculographic technique and the head position with a potentiometer on the helmet.When a peripheral target was lit, the eye made an initial saccade towards it and the head then began to turn towards it. The patients made a gaze shift to the target accurately as the normal subjects. However, decrease in the amplitude and increase in the duration of the head displacement from the values of the normal subject were observed in the patient. Accordingly, the trajectory of eye movement between two groups was different, especially when the target was presented out of the ouclomotor range (over 50 deg). In the patient, time for the gaze to reach the target was significantly longer, and the vestibulo-ocular reflex was almost suppressed during head movements. Moreover, when the subjects were ordered to continue to maintain their gaze direction towards the imaginary target after the target lamp was off, the patient showed a tendency that their gaze gradually deviated to the nasal direction due solely to unsteadiness of the eye position, probably reflecting a loss of appropriate afferent signals form the neck muscles to the oculomotor center.