Harrison James J, Freeman Tom C A, Sumner Petroc
School of Psychology, Cardiff University.
Cardiff University Brain Research Imaging Centre, Cardiff University.
J Exp Psychol Gen. 2014 Oct;143(5):1923-38. doi: 10.1037/a0037021. Epub 2014 May 26.
As a potential exemplar for understanding how volitional actions emerged from reflexes, we studied the relationship between an ancient reflexive gaze stabilization mechanism (optokinetic nystagmus [OKN]) and purposeful eye movements (saccades) that target an object. Traditionally, these have been considered distinct (except in the kinematics of their execution) and have been studied independently. We find that the fast-phases of OKN clearly show properties associated with saccade planning: (a) They are characteristically delayed by irrelevant distractors in an indistinguishable way to saccades (the saccadic inhibition effect), and (b) horizontal OKN fast-phases produce curvature in vertical targeting saccades, just like a competing saccade plan. Thus, we argue that the saccade planning network plays a role in the production of OKN fast-phases, and we question the need for a strict distinction between eye movements that appear to be automatic or volitional. We discuss whether our understanding might benefit from shifting perspective and considering the entire "saccade" system to have developed from an increasingly sophisticated OKN system.
作为理解意志行动如何从反射中产生的一个潜在范例，我们研究了一种古老的反射性眼球稳定机制（视动性眼震[OKN]）与针对物体的有目的眼球运动（扫视）之间的关系。传统上，这些被认为是不同的（除了它们执行时的运动学特征），并且是独立研究的。我们发现，OKN的快相明显表现出与扫视计划相关的特性：（a）它们的特征是被无关干扰物延迟，这与扫视的延迟方式难以区分（扫视抑制效应），并且（b）水平OKN快相在垂直目标扫视中产生曲率，就像一个竞争的扫视计划一样。因此，我们认为扫视计划网络在OKN快相的产生中起作用，并且我们质疑是否有必要严格区分看似自动或意志性的眼球运动。我们讨论了我们的理解是否可能从转变视角中受益，并考虑整个“扫视”系统是从日益复杂的OKN系统发展而来的。
