Multisensory Perception of Self Motion: Psychophysics and Functional Neuroanatomy

我们的感官系统通过触觉、听觉、视觉、嗅觉和味觉来体验环境。此外，我们还有前庭器官，它告诉我们自我运动，从而有助于保持平衡和姿势。前庭热刺激将与视觉刺激相结合，分析视觉和前庭感觉系统在自我运动知觉中的相互作用。我们希望利用这些刺激模式来研究模拟自我运动过程中的神经相互作用。为此，我们将使用一致和不一致的视觉前庭刺激组合来研究它们对自我运动感知、光流场的方向辨别以及相应的自我运动感知的神经元关联的影响。我们将使用功能磁共振成像（fMRI）的方法来测量健康参与者的大脑活动。此外，弥散加权MRI方法将结合概率纤维跟踪来分析前庭和视觉皮质区域之间的解剖连通性。通过比较人类大脑在休息时（即休息状态）的结构和功能连接，将显示视觉-前庭网络的各个部分是如何相互连接的。最后，我们将研究前庭皮层在视觉运动处理过程中的抑制作用。当注意力集中在移动的视觉刺激上时，前庭皮层的活动被抑制。我们的目的是使用重复经颅磁刺激（TMS）和功能性MRI的方法来确定这种抑制在前庭皮层的神经元来源。这些研究结果将为自我运动知觉中视觉和前庭信息的多感觉整合提供新的见解。

With our sensory systems we experience our environment through touch, hearing, sight, smell and taste. In addition, we have vestibular organs, which inform us about self motion and thus contribute to maintaining balance and posture. Caloric vestibular stimulation will be combined with visual stimulation to analyze the interaction between the visual and vestibular sensory systems in self-motion perception. We want to use these modes of stimulation to study the neural interactions during simulated self motion. For this purpose, congruent and incongruent visual-vestibular stimulus combinations will be used to investigate their influence on the perception of self motion, on direction discrimination of optic-flow fields and on the corresponding neuronal correlates of the self-motion perception. We will measure brain activity in healthy participants using the method of functional magnetic resonance imaging (fMRI).In addition, the method of diffusion-weighted MRI will be used in conjunction with probabilistic fiber tracking to analyze the anatomical connectivity between vestibular and visual cortical regions. By comparing the structural and functional connectivity of the human brain at rest (i.e., resting state), it will be shown how parts of the visual-vestibular network are interconnected.Finally, the suppression of the vestibular cortex will be examined during the processing of visual motion. When attention is focused on moving visual stimuli, activity in the vestibular cortex is suppressed. Our aim is to use the method of repetitive transcranial magnetic stimulation (TMS) and functional MRI to determine the neuronal source of this inhibition in the vestibular cortex. The results of these investigations should provide new insights into the multisensory integration of visual and vestibular information in self-motion perception.