Inst. for Psychology, University of Muenster, Muenster, Germany.
J Neurophysiol. 2011 Nov;106(5):2536-45. doi: 10.1152/jn.00023.2011. Epub 2011 Jul 27.
Saccades are used by the visual system to explore visual space with the high accuracy of the fovea. The visual error after the saccade is used to adapt the control of subsequent eye movements of the same amplitude and direction in order to keep saccades accurate. Saccadic adaptation is thus specific to saccade amplitude and direction. In the present study we show that saccadic adaptation is also specific to the initial position of the eye in the orbit. This is useful, because saccades are normally accompanied by head movements and the control of combined head and eye movements depends on eye position. Many parts of the saccadic system contain eye position information. Using the intrasaccadic target step paradigm, we adaptively reduced the amplitude of reactive saccades to a suddenly appearing target at a selective position of the eyes in the orbitae and tested the resulting amplitude changes for the same saccade vector at other starting positions. For central adaptation positions the saccade amplitude reduction transferred completely to eccentric starting positions. However, for adaptation at eccentric starting positions, there was a reduced transfer to saccades from central starting positions or from eccentric starting positions in the opposite hemifield. Thus eye position information modifies the transfer of saccadic amplitude changes in the adaptation of reactive saccades. A gain field mechanism may explain the eye position dependence found.
扫视是视觉系统用来高精度探索视觉空间的方法，它利用中央凹的优势。扫视后的视觉误差用于适应后续具有相同幅度和方向的眼球运动的控制，以保持扫视的准确性。因此，扫视适应是特定于扫视幅度和方向的。在本研究中，我们表明扫视适应也特定于眼球在轨道中的初始位置。这很有用，因为通常扫视伴随着头部运动，而头部和眼睛的联合运动控制取决于眼睛位置。扫视系统的许多部分都包含眼睛位置信息。使用眼内目标步距范式，我们自适应地减少了对突然出现在眼球选择性位置的目标的反应性扫视的幅度，并测试了在其他起始位置上相同扫视矢量的结果幅度变化。对于中央适应位置，扫视幅度的减小完全转移到偏心起始位置。然而，对于偏心起始位置的适应，从中央起始位置或相反视野中的偏心起始位置进行的扫视的转移减少。因此，眼睛位置信息修改了反应性扫视适应中扫视幅度变化的转移。增益场机制可以解释发现的眼睛位置依赖性。
