Blankenburg Felix, Ruff Christian C, Deichmann Ralf, Rees Geraint, Driver Jon
UCL Institute of Cognitive Neuroscience, Department of Psychology, University College London, London, United Kingdom.
PLoS Biol. 2006 Mar;4(3):e69. doi: 10.1371/journal.pbio.0040069. Epub 2006 Feb 28.
We used functional magnetic resonance imaging (fMRI) to study neural correlates of a robust somatosensory illusion that can dissociate tactile perception from physical stimulation. Repeated rapid stimulation at the wrist, then near the elbow, can create the illusion of touches at intervening locations along the arm, as if a rabbit hopped along it. We examined brain activity in humans using fMRI, with improved spatial resolution, during this version of the classic cutaneous rabbit illusion. As compared with control stimulation at the same skin sites (but in a different order that did not induce the illusion), illusory sequences activated contralateral primary somatosensory cortex, at a somatotopic location corresponding to the filled-in illusory perception on the forearm. Moreover, the amplitude of this somatosensory activation was comparable to that for veridical stimulation including the intervening position on the arm. The illusion additionally activated areas of premotor and prefrontal cortex. These results provide direct evidence that illusory somatosensory percepts can affect primary somatosensory cortex in a manner that corresponds somatotopically to the illusory percept.
我们使用功能磁共振成像（fMRI）来研究一种强烈的体感错觉的神经关联，这种错觉能够将触觉感知与物理刺激区分开来。先在手腕处，然后在肘部附近反复进行快速刺激，能够在手臂中间位置产生触摸错觉，就好像有只兔子沿着手臂跳跃一样。我们在人类身上利用具有更高空间分辨率的fMRI，对这种经典的皮肤兔错觉版本进行了脑活动检测。与在相同皮肤部位进行的对照刺激（但顺序不同，不会诱发错觉）相比，错觉序列激活了对侧初级体感皮层，其躯体定位位置对应于前臂上填充的错觉感知。此外，这种体感激活的幅度与包括手臂中间位置的真实刺激的幅度相当。这种错觉还激活了运动前区和前额叶皮层区域。这些结果提供了直接证据，表明虚幻的体感知觉能够以与错觉知觉躯体定位对应的方式影响初级体感皮层。
