Eye movement sequence generation in humans: Motor or goal updating?
Eye movement sequence generation in humans: Motor or goal updating?
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DOI：
10.1167/10.14.28
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发表时间：
2010-01-01
影响因子：
1.8
通讯作者：
Smith, Maurice A.
中科院分区：
文献类型：
--
作者：
Quaia, Christian;Joiner, Wilsaan M.;Smith, Maurice A.
扫视眼球运动通常以预先编程的序列分组。目前对序列中每个扫视产生的机制知之甚少。一般来说，有两种替代方案是可能的：首先，在每次扫视之后，可以估计下一个目标的视网膜位置，并且可以生成适当的扫视。我们称之为目标更新假说。或者，可以预先计算多个运动计划，然后可以在每次运动后更新它们。我们称之为运动更新假说。我们使用McLaughlin的内扫视步骤范例来人为地创建一个条件，在该条件下，这两个假设做出可辨别的预测。我们发现，在人类受试者中，当序列的两个眼跳计划，电机更新假设预测的着陆位置的第二眼跳在两个眼跳序列比目标更新假设。这一发现表明，人类扫视系统能够通过规划多个运动命令来执行对多个目标的扫视序列，然后通过连续减去正在进行的运动输出来更新所述运动命令。
Saccadic eye movements are often grouped in pre-programmed sequences. The mechanism underlying the generation of each saccade in a sequence is currently poorly understood. Broadly speaking, two alternative schemes are possible: first, after each saccade the retinotopic location of the next target could be estimated, and an appropriate saccade could be generated. We call this the goal updating hypothesis. Alternatively, multiple motor plans could be pre-computed, and they could then be updated after each movement. We call this the motor updating hypothesis. We used McLaughlin's intra-saccadic step paradigm to artificially create a condition under which these two hypotheses make discriminable predictions. We found that in human subjects, when sequences of two saccades are planned, the motor updating hypothesis predicts the landing position of the second saccade in two-saccade sequences much better than the goal updating hypothesis. This finding suggests that the human saccadic system is capable of executing sequences of saccades to multiple targets by planning multiple motor commands, which are then updated by serial subtraction of ongoing motor output.