Brandt T, Bartenstein P, Janek A, Dieterich M
Department of Neurology, Ludwig-Maximilians-University, Klinikum Grosshadern, Munich, Germany.
Brain. 1998 Sep;121 ( Pt 9):1749-58. doi: 10.1093/brain/121.9.1749.
The vestibular system--a sensor of head accelerations--cannot detect self-motion at constant velocity and thus requires supplementary visual information. The perception of self-motion during constant velocity movement is completely dependent on visually induced vection. This can be linear vection or circular vection (CV). CV is induced by large-field visual motion stimulation during which the stationary subject perceives the moving surroundings as being stable and himself as being moved. To determine the unknown cortical visual-vestibular interaction during CV, we conducted a PET activation study on CV in 10 human volunteers. The PET images of cortical areas activated during visual motion stimulation without CV were compared with those with CV. Hitherto, CV was explained neurophysiologically by visual-vestibular convergence with activation of the vestibular nuclei, thalamic subnuclei and vestibular cortex. If CV were mediated by the vestibular cortex, one would expect that an adequate visual motion stimulus would activate both the visual and vestibular cortex. Contrary to this expectation, it was shown for the first time that visual motion stimulation with CV not only activates a medial parieto-occipital visual area bilaterally, separate from middle temporal/medial superior temporal areas, it also simultaneously deactivates the parieto-insular vestibular cortex. There was a positive correlation between the perceived intensity of CV and relative changes in regional CBF in parietal and occipital areas. These findings support a new functional interpretation: reciprocal inhibitory visual-vestibular interaction as a multisensory mechanism for self-motion perception. Inhibitory visual-vestibular interaction might protect visual perception of self-motion from potential vestibular mismatches caused by involuntary head accelerations during locomotion, and this would allow the dominant sensorial weight during self-motion perception to shift from one sensory modality to the other.
前庭系统——一种头部加速度传感器——无法检测匀速运动时的自身运动，因此需要补充视觉信息。匀速运动过程中的自身运动感知完全依赖于视觉诱发的运动错觉。这可以是线性运动错觉或圆周运动错觉（CV）。CV由大视野视觉运动刺激诱发，在此期间静止的受试者会将移动的周围环境视为稳定，而将自己视为在移动。为了确定CV过程中未知的皮质视觉 - 前庭相互作用，我们对10名人类志愿者进行了关于CV的正电子发射断层扫描（PET）激活研究。将无CV的视觉运动刺激期间激活的皮质区域的PET图像与有CV时的图像进行了比较。迄今为止，CV在神经生理学上被解释为视觉 - 前庭汇聚，伴有前庭核、丘脑亚核和前庭皮质的激活。如果CV是由前庭皮质介导的，人们会预期适当的视觉运动刺激会同时激活视觉皮质和前庭皮质。与这一预期相反，首次发现伴有CV的视觉运动刺激不仅双侧激活了一个内侧顶枕视觉区域，该区域与颞中/颞上内侧区域分开，还同时使顶岛前庭皮质失活。CV的感知强度与顶叶和枕叶区域局部脑血流量的相对变化之间存在正相关。这些发现支持了一种新的功能解释：相互抑制的视觉 - 前庭相互作用作为自身运动感知的多感官机制。抑制性视觉 - 前庭相互作用可能会保护自身运动的视觉感知免受运动过程中不自主头部加速度引起的潜在前庭不匹配的影响，这将使自身运动感知过程中的主导感官权重从一种感觉模态转移到另一种感觉模态。
