Collins Thérèse, Vergilino-Perez Dorine, Delisle Laura, Doré-Mazars Karine
Laboratory de Psychologie et Neurosciences Cognitives, Paris Descartes University and CNRS, 71 avenue E. Vaillant, Boulogne-Billancourt, France.
J Neurophysiol. 2008 May;99(5):2708-18. doi: 10.1152/jn.01082.2007. Epub 2008 Mar 26.
In the antisaccade task, subjects must execute an eye movement away from a visual target. Correctly executing an antisaccade requires inhibiting a prosaccade toward the visual target and programming a movement to the opposite side. This movement could be based on the inversion of the visual vector, corresponding to the distance between the fixation point and the visual target, or the motor vector of the unwanted prosaccade. We dissociated the two vectors by means of saccadic adaptation. Adaptation can be observed when systematic targeting errors are caused by the displacement of the visual target during the saccade. Adaptation progressively modifies saccade amplitude (defined by the motor vector) such that it becomes appropriate to the postsaccadic stimulus position and thus different from the visual vector of the target. If antisaccade preparation depended on visual vector inversion, rightward prosaccade adaptation should not transfer to leftward antisaccades (which are based on the same visual vector) but should transfer to rightward antisaccades (which are based on a visual vector inside the adaptation field). If antisaccade preparation depended on motor vector inversion, rightward prosaccade adaptation should transfer to leftward antisaccades (which are based on the same, adapted motor vector) but should not transfer to rightward antisaccades (which are based on a nonadapted motor vector). The results are in line with the first hypothesis, showing that vector inversion precedes saccadic adaptation and suggesting that antisaccade preparation depends on the inversion of the visual target vector.
在反扫视任务中，受试者必须执行远离视觉目标的眼动。正确执行反扫视需要抑制朝向视觉目标的顺向扫视，并规划向相反方向的眼动。这种眼动可以基于视觉矢量的反转，该反转对应于注视点与视觉目标之间的距离，或者基于不需要的顺向扫视的运动矢量。我们通过扫视适应来区分这两个矢量。当扫视过程中视觉目标的位移导致系统性的目标误差时，就可以观察到适应现象。适应会逐渐改变扫视幅度（由运动矢量定义），使其与扫视后的刺激位置相匹配，从而与目标的视觉矢量不同。如果反扫视准备依赖于视觉矢量反转，那么向右的顺向扫视适应不应转移到向左的反扫视（基于相同的视觉矢量），而应转移到向右的反扫视（基于适应场内的视觉矢量）。如果反扫视准备依赖于运动矢量反转，那么向右的顺向扫视适应应转移到向左的反扫视（基于相同的、已适应的运动矢量），而不应转移到向右的反扫视（基于未适应的运动矢量）。结果与第一个假设一致，表明矢量反转先于扫视适应，并表明反扫视准备依赖于视觉目标矢量的反转。
