Lunghi Claudia, Lo Verde Luca, Alais David
Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Italy; Institute of Neuroscience, CNR, Pisa, Italy.
Institute of Neuroscience, CNR, Pisa, Italy; Department NEUROFARBA, University of Florence, Italy.
Iperception. 2017 Jan 1;8(1):2041669516686986. doi: 10.1177/2041669516686986. eCollection 2017 Jan-Feb.
To efficiently interact with the external environment, our nervous system combines information arising from different sensory modalities. Recent evidence suggests that cross-modal interactions can be automatic and even unconscious, reflecting the ecological relevance of cross-modal processing. Here, we use continuous flash suppression (CFS) to directly investigate whether haptic signals can interact with visual signals outside of visual awareness. We measured suppression durations of visual gratings rendered invisible by CFS either during visual stimulation alone or during visuo-haptic stimulation. We found that active exploration of a haptic grating congruent in orientation with the suppressed visual grating reduced suppression durations both compared with visual-only stimulation and to incongruent visuo-haptic stimulation. We also found that the facilitatory effect of touch on visual suppression disappeared when the visual and haptic gratings were mismatched in either spatial frequency or orientation. Together, these results demonstrate that congruent touch can accelerate the rise to consciousness of a suppressed visual stimulus and that this unconscious cross-modal interaction depends on visuo-haptic congruency. Furthermore, since CFS suppression is thought to occur early in visual cortical processing, our data reinforce the evidence suggesting that visuo-haptic interactions can occur at the earliest stages of cortical processing.
为了有效地与外部环境互动，我们的神经系统会整合来自不同感觉模态的信息。最近的证据表明，跨模态交互可以是自动的，甚至是无意识的，这反映了跨模态处理的生态相关性。在这里，我们使用连续闪光抑制（CFS）来直接研究触觉信号是否能在视觉意识之外与视觉信号相互作用。我们测量了在单独视觉刺激或视觉 - 触觉刺激期间，被CFS抑制而不可见的视觉光栅的抑制持续时间。我们发现，与仅视觉刺激以及视觉 - 触觉刺激不匹配的情况相比，主动探索与被抑制视觉光栅方向一致的触觉光栅会缩短抑制持续时间。我们还发现，当视觉和触觉光栅在空间频率或方向上不匹配时，触觉对视觉抑制的促进作用就会消失。总之，这些结果表明，一致的触觉可以加速被抑制视觉刺激的意识恢复，并且这种无意识的跨模态交互依赖于视觉 - 触觉的一致性。此外，由于CFS抑制被认为发生在视觉皮层处理的早期阶段，我们的数据进一步证明了视觉 - 触觉交互可以在皮层处理的最早阶段发生。
