Dissociating vestibular and somatosensory contributions to spatial orientation
Dissociating vestibular and somatosensory contributions to spatial orientation
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DOI：
10.1152/jn.00056.2016
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发表时间：
2016-07-01
影响因子：
2.5
通讯作者：
Tarnutzer, Alexander A.
中科院分区：
文献类型：
--
作者：
Alberts, Bart B. G. T.;Selen, Luc P. J.;Tarnutzer, Alexander A.
推断物体在周围环境中的方向很大程度上取决于我们对重力方向的内在感觉。先前的研究表明，这种感觉是基于多种信息源的整合，包括视觉，前庭（耳石）和体感信号。这些传感器的个体噪声特性和贡献可以使用空间定向任务（诸如主观视觉垂直（SVV）任务）来研究。最近的一项研究报道，完全双侧前庭丧失的患者在这些任务上的表现与健康对照相似，由此证实，耳石和身体体感的噪声水平都是侧倾-倾斜依赖的。在这里，我们测试了这一假设在10个健康的人类受试者滚动倾斜的头部相对于身体分离倾斜角依赖性的耳石和体感噪声。使用心理测量的方法，我们测量了感知的方向，和它的变化，相对于重力垂直（SVV）的一个短暂的闪光线。在多个身体空间取向（-90至90度，30度步长）和头对身体滚动倾斜（左耳向下30度，对齐，右耳向下30度）下进行测量。结果表明，垂直知觉是在一个头部在空间的参考框架，与系统SVV错误，增加了较大的头部在空间的方向。变异模式表明一个较大的贡献，耳石器官周围直立和更大的身体在空间滚动倾斜的身体体感的贡献。模拟结果表明，这些研究结果是一致的统计模型，涉及倾斜相关的噪声水平的耳石和体感信号，确认动态变化的重量与倾斜角的感觉输入。
Inferring object orientation in the surroundings heavily depends on our internal sense of direction of gravity. Previous research showed that this sense is based on the integration of multiple information sources, including visual, vestibular (otolithic), and somatosensory signals. The individual noise characteristics and contributions of these sensors can be studied using spatial orientation tasks, such as the subjective visual vertical (SVV) task. A recent study reported that patients with complete bilateral vestibular loss perform similar as healthy controls on these tasks, from which it was conjectured that the noise levels of both otoliths and body somatosensors are roll-tilt dependent. Here, we tested this hypothesis in 10 healthy human subjects by roll tilting the head relative to the body to dissociate tilt-angle dependencies of otolith and somatosensory noise. Using a psychometric approach, we measured the perceived orientation, and its variability, of a briefly flashed line relative to the gravitational vertical (SVV). Measurements were taken at multiple body-in-space orientations (-90 to 90 degrees, steps of 30 degrees) and head-on-body roll tilts (30 degrees left ear down, aligned, 30 degrees right ear down). Results showed that verticality perception is processed in a head-in-space reference frame, with a systematic SVV error that increased with larger head-in-space orientations. Variability patterns indicated a larger contribution of the otolith organs around upright and a more substantial contribution of the body somatosensors at larger body-in-space roll tilts. Simulations show that these findings are consistent with a statistical model that involves tilt-dependent noise levels of both otolith and somatosensory signals, confirming dynamic shifts in the weights of sensory inputs with tilt angle.