Akyuz Sibel, Pavan Andrea, Kaya Utku, Kafaligonul Hulusi
Interdisciplinary Neuroscience Program, Bilkent University, Ankara, Turkey; National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey; Faculty of Arts and Sciences, Osmaniye Korkut Ata University, Osmaniye, Turkey.
School of Psychology, University of Lincoln, Lincoln, UK.
Cortex. 2020 Apr;125:122-134. doi: 10.1016/j.cortex.2019.12.015. Epub 2020 Jan 2.
Adaptation is essential to interact with a dynamic and changing environment, and can be observed on different timescales. Previous studies on a motion paradigm called dynamic motion aftereffect (dMAE) showed that neural adaptation can establish even in very short timescales. However, the neural mechanisms underlying such rapid form of neural plasticity is still debated. In the present study, short- and long-term forms of neural plasticity were investigated using dynamic motion aftereffect combined with EEG (Electroencephalogram). Participants were adapted to directional drifting gratings for either short (640 msec) or long (6.4 sec) durations. Both adaptation durations led to motion aftereffects on the perceived direction of a dynamic and directionally ambiguous test pattern, but the long adaptation produced stronger dMAE. In line with behavioral results, we found robust changes in the event-related potentials elicited by the dynamic test pattern within 64-112 msec time range. These changes were mainly clustered over occipital and parieto-occipital scalp sites. Within this time range, the aftereffects induced by long adaptation were stronger than those by short adaptation. Moreover, the aftereffects by each adaptation duration were in the opposite direction. Overall, these EEG findings suggest that dMAEs reflect changes in cortical areas mediating low- and mid-level visual motion processing. They further provide evidence that short- and long-term forms of motion adaptation lead to distinct changes in neural activity, and hence support the view that adaptation is an active time-dependent process which involves different neural mechanisms.
适应对于与动态变化的环境进行交互至关重要，并且可以在不同的时间尺度上观察到。先前关于一种称为动态运动后效（dMAE）的运动范式的研究表明，即使在非常短的时间尺度上也能建立神经适应。然而，这种快速神经可塑性形式背后的神经机制仍存在争议。在本研究中，使用动态运动后效结合脑电图（EEG）研究了神经可塑性的短期和长期形式。参与者分别适应了短（640毫秒）或长（6.4秒）持续时间的定向漂移光栅。两种适应持续时间都导致了对动态且方向模糊的测试图案的感知方向产生运动后效，但长时间适应产生了更强的dMAE。与行为结果一致，我们发现在64 - 112毫秒时间范围内，动态测试图案诱发的事件相关电位有显著变化。这些变化主要集中在枕叶和顶枕头皮部位。在这个时间范围内，长时间适应诱发的后效比短时间适应更强。此外，每种适应持续时间产生的后效方向相反。总体而言，这些脑电图结果表明，dMAE反映了介导低水平和中等水平视觉运动处理的皮层区域的变化。它们进一步提供了证据，表明短期和长期形式的运动适应会导致神经活动的明显变化，因此支持了这样一种观点，即适应是一个活跃的时间依赖性过程，涉及不同的神经机制。
