Antiphasic 40 Hz Oscillatory Current Stimulation Affects Bistable Motion Perception
Antiphasic 40 Hz Oscillatory Current Stimulation Affects Bistable Motion Perception
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DOI：
10.1007/s10548-013-0294-x
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发表时间：
2014-01-01
期刊：
影响因子：
2.7
通讯作者：
Herrmann, Christoph S.
中科院分区：
文献类型：
--
作者：
Strueber, Daniel;Rach, Stefan;Herrmann, Christoph S.
当看到模糊的刺激时，意识知觉会自发地在对物理上未改变的刺激信息的相互竞争的解释之间交替。作为感知开关背后的一种可能的神经机制，有人认为神经元动态地改变其在伽马频带（30-80 Hz）中同步振荡活动的模式。为了支持这一假设，人类脑电图 (EEG) 研究提供了模糊知觉期间伽玛波段调制的相关证据。为了确定本研究中伽马能带振荡的因果作用，我们在呈现双稳态视运动刺激（可以被感知为水平或垂直移动）时，在两个半球的枕顶叶区域应用 40 Hz 的经颅交流电刺激 (tACS)。在这种范式中，水平和垂直视运动之间的切换可能涉及半球间功能耦合的变化。我们检查了伽玛 tACS 对感知水平和垂直运动持续时间以及半球间脑电图一致性的影响，发现感知水平运动比例下降，同时半球间伽玛波段一致性增加。在使用 6 Hz tACS 的对照实验中，我们没有观察到任何刺激对行为或连贯性的影响。此外，与具有 0A 度相位差的同相刺激相比，40 Hz 的外部刺激仅在半球之间施加 180A 度相位差（反相）时才有效。这些发现表明，半球之间外部不同步的伽马振荡会损害半球间运动整合，进而使双稳态表观运动的意识体验产生偏差。
When viewing ambiguous stimuli, conscious perception alternates spontaneously between competing interpretations of physically unchanged stimulus information. As one possible neural mechanism underlying the perceptual switches, it has been suggested that neurons dynamically change their pattern of synchronized oscillatory activity in the gamma band (30-80 Hz). In support of this hypothesis, there is correlative evidence from human electroencephalographic (EEG) studies for gamma band modulations during ambiguous perception. To establish a causal role of gamma band oscillations in the current study, we applied transcranial alternating current stimulation (tACS) at 40 Hz over occipital-parietal areas of both hemispheres during the presentation of bistable apparent motion stimuli that can be perceived as moving either horizontally or vertically. In this paradigm, the switch between horizontal and vertical apparent motion is likely to involve a change in interhemispheric functional coupling. We examined gamma tACS effects on the durations of perceived horizontal and vertical motion as well as on interhemispheric EEG coherence and found a decreased proportion of perceived horizontal motion together with an increase of interhemispheric gamma band coherence. In a control experiment using 6 Hz tACS, we did not observe any stimulation effects on behavior or coherence. Furthermore, external stimulation at 40 Hz was only effective when applied with 180A degrees phase difference between hemispheres (anti-phase), as compared to in-phase stimulation with 0A degrees phase difference. These findings suggest that externally desynchronizing gamma oscillations between hemispheres impairs interhemispheric motion integration and in turn biases conscious experience of bistable apparent motion.