School of Psychology, University of St Andrews, UK.
School of Psychology, University of St Andrews, UK.
Neuroimage. 2020 Sep;218:116973. doi: 10.1016/j.neuroimage.2020.116973. Epub 2020 May 25.
When two objects are presented in alternation at two locations, they are seen as a single object moving from one location to the other. This apparent motion (AM) percept is experienced for objects located at short and also at long distances. However, current models cannot explain how the brain integrates information over large distances to create such long-range AM. This study investigates the neural markers of AM by parcelling out the contribution of spatial and temporal interactions not specific to motion. In two experiments, participants' EEG was recorded while they viewed two stimuli inducing AM. Different combinations of these stimuli were also shown in a static context to predict an AM neural response where no motion is perceived. We compared the goodness of fit between these different predictions and found consistent results in both experiments. At short-range, the addition of the inhibitory spatial and temporal interactions not specific to motion improved the AM prediction. However, there was no indication that spatial or temporal non-linear interactions were present at long-range. This suggests that short- and long-range AM rely on different neural mechanisms. Importantly, our results also show that at both short- and long-range, responses generated by a moving stimulus could be well predicted from conditions in which no motion is perceived. That is, the EEG response to a moving stimulus is simply a combination of individual responses to non-moving stimuli. This demonstrates a dissociation between the brain response and the subjective percept of motion.
当两个物体在两个位置交替出现时,它们会被视为从一个位置移动到另一个位置的单个物体。这种明显的运动(AM)感知既可以在短距离也可以在长距离的物体上体验到。然而,当前的模型无法解释大脑如何整合远距离的信息来产生这种长距离的 AM。本研究通过区分与运动无关的空间和时间相互作用的贡献,来研究 AM 的神经标记物。在两项实验中,参与者在观看两个诱导 AM 的刺激时记录了他们的 EEG。这些刺激的不同组合也在静态背景下呈现,以预测感知不到运动的 AM 神经反应。我们比较了这些不同预测的拟合优度,在两项实验中都得到了一致的结果。在短距离上,添加与运动无关的抑制性空间和时间相互作用可以改善 AM 预测。然而,没有迹象表明在长距离上存在空间或时间非线性相互作用。这表明短距离和长距离的 AM 依赖于不同的神经机制。重要的是,我们的结果还表明,在短距离和长距离上,由移动刺激产生的反应可以很好地从感知不到运动的条件中预测出来。也就是说,移动刺激的 EEG 反应只是对非移动刺激的个体反应的组合。这证明了大脑反应和运动的主观感知之间的分离。