Zaretskaya Natalia, Bartels Andreas
Vision and Cognition Lab, Centre for Integrative Neuroscience, University of Tübingen, Tübingen 72076, Germany.
Curr Biol. 2013 Oct 21;23(20):R919-20. doi: 10.1016/j.cub.2013.09.002.
Binocular rivalry occurs when two distinct visual stimuli are presented separately to each eye, causing perceptual ambiguity. The conscious state of the observer then alternates between the perceptual dominance of one of the stimuli while the other is suppressed, and vice versa. These vivid changes in perception during constant visual stimulation allow the study of brain processes involved in conscious visual experience. There is abundant electrophysiological as well as fMRI evidence that neural activity in stimulus-selective areas of the temporal lobe correlates with perceptual changes during rivalry [1–3]. Yet, almost nothing is known about the causal contribution of these areas to dominance and suppression of their preferred stimulus. We induced binocular rivalry in human observers using moving dots presented to one eye and a static face to the other eye, and applied transcranial magnetic stimulation (TMS) over the motion area V5/hMT+. We show that disrupting activity in V5/hMT+ during rivalry extends periods of motion suppression, with no effect on periods of motion dominance, revealing a state-specific contribution of V5/hMT+ to the competition for awareness in rivalry.
当两个不同的视觉刺激分别呈现给每只眼睛时，就会出现双眼竞争，从而导致感知模糊。观察者的意识状态随后会在一种刺激的感知主导（此时另一种刺激被抑制）和另一种刺激的感知主导（此时前一种刺激被抑制）之间交替。在持续的视觉刺激过程中，这些感知上的生动变化使得对有意识视觉体验中涉及的大脑过程的研究成为可能。有大量的电生理以及功能磁共振成像证据表明，颞叶刺激选择性区域的神经活动与竞争过程中的感知变化相关[1-3]。然而，对于这些区域对其偏好刺激的主导和抑制的因果贡献，人们几乎一无所知。我们让人类观察者通过一只眼睛观看移动的点，另一只眼睛观看静态的面部来诱发双眼竞争，并在运动区域V5/hMT+上方施加经颅磁刺激（TMS）。我们发现，在竞争过程中干扰V5/hMT+的活动会延长运动抑制期，而对运动主导期没有影响，这揭示了V5/hMT+在竞争意识的过程中对特定状态的贡献。
