INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center, IMPACT (Integrative, Multisensory, Perception, Action and Cognition) Team and University Lyon 1, Lyon, France.
PLoS One. 2011 Feb 23;6(2):e17329. doi: 10.1371/journal.pone.0017329.
When goal-directed movements are inaccurate, two responses are generated by the brain: a fast motor correction toward the target and an adaptive motor recalibration developing progressively across subsequent trials. For the saccadic system, there is a clear dissociation between the fast motor correction (corrective saccade production) and the adaptive motor recalibration (primary saccade modification). Error signals used to trigger corrective saccades and to induce adaptation are based on post-saccadic visual feedback. The goal of this study was to determine if similar or different error signals are involved in saccadic adaptation and in corrective saccade generation. Saccadic accuracy was experimentally altered by systematically displacing the visual target during motor execution. Post-saccadic error signals were studied by manipulating visual information in two ways. First, the duration of the displaced target after primary saccade termination was set at 15, 50, 100 or 800 ms in different adaptation sessions. Second, in some sessions, the displaced target was followed by a visual mask that interfered with visual processing. Because they rely on different mechanisms, the adaptation of reactive saccades and the adaptation of voluntary saccades were both evaluated. We found that saccadic adaptation and corrective saccade production were both affected by the manipulations of post-saccadic visual information, but in different ways. This first finding suggests that different types of error signal processing are involved in the induction of these two motor corrections. Interestingly, voluntary saccades required a longer duration of post-saccadic target presentation to reach the same amount of adaptation as reactive saccades. Finally, the visual mask interfered with the production of corrective saccades only during the voluntary saccades adaptation task. These last observations suggest that post-saccadic perception depends on the previously performed action and that the differences between saccade categories of motor correction and adaptation occur at an early level of visual processing.
当目标导向运动不准确时，大脑会产生两种反应：一种是快速向目标运动的修正，另一种是在随后的试验中逐渐发展的适应性运动重新校准。对于眼跳系统，快速运动修正（校正性眼跳产生）和适应性运动重新校准（主要眼跳修正）之间存在明显的分离。用于触发校正性眼跳和诱导适应的误差信号基于眼跳后的视觉反馈。本研究的目的是确定在眼跳适应和校正性眼跳产生中是否涉及类似或不同的误差信号。通过在运动执行过程中系统地偏移视觉目标来改变眼跳的准确性。通过两种方式操纵视觉信息来研究眼跳后的误差信号。首先，在不同的适应阶段，将主要眼跳结束后目标的偏移持续时间设置为 15、50、100 或 800 毫秒。其次，在某些阶段，目标会被一个视觉掩蔽物跟随，从而干扰视觉处理。由于它们依赖于不同的机制，因此评估了反应性眼跳的适应和自愿性眼跳的适应。我们发现，眼跳适应和校正性眼跳产生都受到眼跳后视觉信息操纵的影响，但方式不同。这一发现首先表明，不同类型的误差信号处理参与了这两种运动修正的诱导。有趣的是，自愿性眼跳需要更长的眼跳后目标呈现时间才能达到与反应性眼跳相同的适应量。最后，视觉掩蔽物仅在自愿性眼跳适应任务中干扰校正性眼跳的产生。这些最后的观察结果表明，眼跳后的感知取决于之前执行的动作，并且运动修正和适应的眼跳类别之间的差异发生在视觉处理的早期阶段。
