University of Lincoln, School of Psychology, Brayford Pool, Lincoln LN6 7TS, UK.
University of Lincoln, School of Psychology, Brayford Pool, Lincoln LN6 7TS, UK.
Neuroimage. 2017 Aug 15;157:555-560. doi: 10.1016/j.neuroimage.2017.06.036. Epub 2017 Jun 17.
A long-held view of the visual system is that form and motion are independently analysed. However, there is physiological and psychophysical evidence of early interaction in the processing of form and motion. In this study, we used a combination of Glass patterns (GPs) and repetitive Transcranial Magnetic Stimulation (rTMS) to investigate in human observers the neural mechanisms underlying form-motion integration. GPs consist of randomly distributed dot pairs (dipoles) that induce the percept of an oriented stimulus. GPs can be either static or dynamic. Dynamic GPs have both a form component (i.e., orientation) and a non-directional motion component along the orientation axis. GPs were presented in two temporal intervals and observers were asked to discriminate the temporal interval containing the most coherent GP. rTMS was delivered over early visual area (V1/V2) and over area V5/MT shortly after the presentation of the GP in each interval. The results showed that rTMS applied over early visual areas affected the perception of static GPs, but the stimulation of area V5/MT did not affect observers' performance. On the other hand, rTMS was delivered over either V1/V2 or V5/MT strongly impaired the perception of dynamic GPs. These results suggest that early visual areas seem to be involved in the processing of the spatial structure of GPs, and interfering with the extraction of the global spatial structure also affects the extraction of the motion component, possibly interfering with early form-motion integration. However, visual area V5/MT is likely to be involved only in the processing of the motion component of dynamic GPs. These results suggest that motion and form cues may interact as early as V1/V2.
长期以来，人们认为视觉系统独立地分析形状和运动。然而，生理和心理物理学证据表明，在形状和运动的处理过程中存在早期的相互作用。在这项研究中，我们使用 Glass 图案 (GPs) 和重复经颅磁刺激 (rTMS) 的组合，研究了人类观察者中形状-运动整合的神经机制。GPs 由随机分布的点对 (偶极子) 组成，这些点对会产生定向刺激的感知。GPs 可以是静态的，也可以是动态的。动态 GPs 既有形状成分（即方向），也有沿方向轴的非定向运动成分。GPs 在两个时间间隔内呈现，观察者被要求区分包含最连贯 GPs 的时间间隔。rTMS 在每个间隔呈现 GPs 后立即施加于早期视觉区（V1/V2）和 V5/MT 区。结果表明，施加于早期视觉区的 rTMS 影响了静态 GPs 的感知，但刺激 V5/MT 区并不影响观察者的表现。另一方面，rTMS 施加于 V1/V2 或 V5/MT 区强烈损害了动态 GPs 的感知。这些结果表明，早期视觉区似乎参与了 GPs 空间结构的处理，而干扰全局空间结构的提取也会影响运动成分的提取，可能会干扰早期的形状-运动整合。然而，V5/MT 区可能仅参与动态 GPs 运动成分的处理。这些结果表明，运动和形状线索可能早在 V1/V2 区就相互作用。
