The role of early visual cortex (V1/V2) in conscious and unconscious visual perception
The role of early visual cortex (V1/V2) in conscious and unconscious visual perception
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DOI：
10.1016/j.neuroimage.2010.02.042
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发表时间：
2010-06-01
期刊：
影响因子：
5.7
通讯作者：
Silvanto, Juha
中科院分区：
文献类型：
--
作者：
Koivisto, Mika;Mantyla, Teemu;Silvanto, Juha
纹状体皮质(V1)对纹外反馈反应的“晚期”活动期被认为是视觉意识的标志。然而，尚不清楚这种重复性活动是否完全与知觉有关，或者它是否也是无意识视觉处理所必需的。我们研究了“晚期”V1活动在知觉和不知觉视觉运动知觉中的作用。参与者被要求在一个连贯移动的随机点显示器上做出强制选择方向辨别判断，并另外对他们对刺激的主观知觉进行评级。在运动偏移后20、40、60、80或100ms对早期视皮层(V1/V2)进行经颅磁刺激(TMS)。视觉知觉在“早期”(20ms)和“晚期”(60ms)刺激时间窗中受损。在无TMS基线条件下，受试者在“不知情”试验中的强迫选择方向辨别表现高于机会。重要的是，这种性能在“较晚”的时间窗口被TMS比V1/V2降低。在第二个实验中，我们发现VS/MT的关键时间窗位于V1/V2活动的“早”和“晚”时间窗之间。结果表明，无论是知觉知觉还是不知觉知觉，反复的纹外-V1活动都是必要的。(C)2010 Elsevier Inc.保留所有权利。
A "late" period of activity in striate cortex (V1) in response to extrastriate feedback has been proposed to act as a marker of visual awareness. It is not clear, however, whether such recurrent activity is associated exclusively with aware perception or whether it is necessary also for unaware visual processing. We investigated the role of the "late" V1 activity in both aware and unaware visual motion perception. Participants were asked to make a forced-choice direction discrimination judgment on a coherently moving random-dot display and additionally rate their subjective awareness of the stimulus. Transcranial magnetic stimulation (TMS) was applied over the early visual cortex (V1/V2) either 20, 40, 60, 80, or 100 ms after motion offset. Visual awareness was impaired at an "early" (20 ms) and a "late" (60 ms) stimulation time window. Participants' forced-choice direction discrimination performance on "unaware" trials was above chance in No TMS baseline condition. Importantly, this performance was impaired by TMS over V1/V2 at the "late" time window. In a second experiment we show that the critical time window of VS/MT falls between the "early" and "late" time windows of V1/V2 activity. The results indicate that recurrent extrastriate-V1 activity is necessary for both aware and unaware perception. (C) 2010 Elsevier Inc. All rights reserved.