The Department of Psychology, University of Turku, Assistentinkatu 7, 20014 Turku, Finland; Centre for Cognitive Neuroscience, University of Turku, Finland.
The Department of Psychology, University of Turku, Assistentinkatu 7, 20014 Turku, Finland; Centre for Cognitive Neuroscience, University of Turku, Finland.
Neuropsychologia. 2019 May;128:223-231. doi: 10.1016/j.neuropsychologia.2017.11.013. Epub 2017 Nov 11.
Primary visual cortex (V1) and extrastriate V2 are necessary for the emergence of visual consciousness, but the effects of involvement of extrastriate V3 on visual consciousness is unclear. The objective of this study was to examine the causal role of V3 in visual consciousness in humans. We combined neuronavigated transcranial magnetic stimulation (TMS) with a computational model of the TMS-induced electric field to test whether or not the intact processing of visual input in V3, like in V1 and V2, is necessary for conscious visual perception. We targeted the stimulation both to V2 and to V3. If TMS of V3 blocks conscious visual perception of stimuli, then activation in V3 is a causally necessary prerequisite for conscious perception of stimuli. According to the alternative hypothesis, TMS of V3 will not block the conscious visual perception of stimuli, because the pathways from V1 to the higher cortical areas that go around V3 provide sufficient visual input for the emergence of conscious visual perception. The results showed that TMS interfered with conscious perception of features, detection of stimulus presence and the ability to discriminate the letter stimuli both when TMS was targeted either to V3 or to V2. For the conscious detection of stimulus presence, the effect was significantly stronger when V2 was stimulated than when V3 was stimulated. The results of the present study suggest that in addition to the primary visual cortex and V2, also V3 causally contributes to the generation of the most basic form of visual consciousness. Importantly, the results also indicate that V3 is necessary for visual perception in general, not only for visual consciousness.
初级视皮层（V1）和外侧纹状 V2 是视觉意识出现的必要条件，但外侧纹状 V3 的参与对视觉意识的影响尚不清楚。本研究的目的是检验 V3 在人类视觉意识中的因果作用。我们将神经导航经颅磁刺激（TMS）与 TMS 诱导电场的计算模型相结合，以测试 V3 中视觉输入的完整处理是否像 V1 和 V2 一样，对于有意识的视觉感知是必要的。我们将刺激靶向 V2 和 V3。如果 V3 的 TMS 阻断了对刺激的有意识视觉感知，那么 V3 的激活是有意识感知刺激的因果必要前提。根据替代假设，V3 的 TMS 不会阻断对刺激的有意识视觉感知，因为从 V1 到绕过 V3 的更高皮质区域的通路为有意识的视觉感知的出现提供了足够的视觉输入。结果表明，当 TMS 靶向 V3 或 V2 时，TMS 会干扰对特征的有意识感知、对刺激存在的检测以及区分字母刺激的能力。对于对刺激存在的有意识检测，当刺激 V2 时的效果明显强于刺激 V3 时的效果。本研究的结果表明，除了初级视皮层和 V2 之外，V3 也对生成最基本形式的视觉意识具有因果作用。重要的是，结果还表明，V3 是视觉感知所必需的，不仅是视觉意识。
