Amplitude of human head movements associated with horizontal saccades
Amplitude of human head movements associated with horizontal saccades
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DOI：
10.1007/s002210050715
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发表时间：
1999-05-01
影响因子：
2
通讯作者：
Stahl, JS
中科院分区：
文献类型：
--
作者：
Stahl, JS
人的眼跳可能与头部运动有关，也可能与头部运动无关。到目前为止，几乎没有人注意到决定首长调动征聘和规模的机制。正常人沿着发光二极管的环绕阵列进行水平的离心式扫视。在头部运动结束时(或在眼球运动结束时)测量凝视、珠子和头部眼球角度。我们发现，头部移动幅度(Delta H)以一种简单的方式与眼睛偏心有关，如果没有头部移动的情况下进行凝视转移会导致这种情况。Delta H与这一预测的眼睛偏心率(E-PRED)的曲线图有一个中央平坦区域，在该区域中凝视的移动不伴随头部移动(仅限眼睛的范围)，以及两个侧叶，其中Delta H是E-PRED(眼头范围)的线性函数。Delta H与E-PRED的相关性好于与凝视移位幅度的相关性，如果控制头部运动以将眼睛偏心保持在特定范围内，这一点是可以预期的。头部运动倾向通过只有眼睛的范围的宽度、眼头范围的斜率以及在完成凝视转移行为结束时可能找到眼睛的区域的宽度(习惯的眼球运动范围)来量化。在这些正常受试者中，测量范围很广：仅眼范围(平均值+/-SD)为35.8+/-31.9度，眼头范围斜率为0.77+/-0.16度，习惯性眼球运动范围为44.0+/-23.8度。然而，对于给定的受试者，这些测量在实验过程中是可重复的，通常的眼球运动范围是三个测量中最一致的。Delta H vs.E-PRED图的形式表明，眼睛和头部协调的神经回路执行两个不同的功能--控制头部运动和调节头部运动。头部运动倾向在受试者之间存在很大差异的原因尚不清楚。在完整的眼睛(在轨)范围或完整的颈部范围内，它不能与被试之间的差异相比较。
Human saccades may or may not be associated with head movements. To date, little attention has been devoted to the mechanisms determining head movement recruitment and scaling. Normal human subjects made horizontal, centrifugal saccades along an encircling array of light-emitting diodes. Measurements of gaze, bead, and eye-in-head angle were made at the conclusion of the head movement (or at the end of the eye movement in eye-only saccades). We found that head movement amplitude (Delta H) related in a simple fashion to the eye eccentricity that would have resulted if the gaze shift had been performed without a head movement. Plots of Delta H vs this predicted eye eccentricity (E-PRED) had a central flat region in which gaze shifts were unaccompanied by head movements (the eye-only range) and two flanking lobes in which Delta H was a linear function of E-PRED (the eye-head ranges). Delta H correlated with E-PRED better than with gaze shift amplitude, as would be expected if head movements were controlled so as to keep eye eccentricity within a particular range. Head movement tendencies were quantified by the width of the eye-only range, the slope of the eye-head range, and the width of the region within which the eye was likely to be found at the conclusion of the completed gaze-shifting behavior (the customary ocular motor range). The measures ranged widely in these normal subjects: 35.8+/-31.9 degrees for the eye-only range (mean+/-SD), 0.77+/-0.16 for the slope of the eye-head range, and 44.0+/-23.8 degrees for the customary ocular motor range. Yet for a given subject, the measurements were reproducible across experimental sessions, with the customary ocular motor range being the most consistent measure of the three. The form of the Delta H vs E-PRED plots suggests that the neural circuitry underlying eye-head coordination carries out two distinct functions - gating the head movement and scaling the head movement. The reason for the large intersubject variability of head movement tendencies is unknown. It does not parallel intersubject differences in full-scale eye (in orbit) range or full-scale neck range.