Multisensory Processing in Spatial Orientation: An Inverse Probabilistic Approach
Multisensory Processing in Spatial Orientation: An Inverse Probabilistic Approach
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DOI：
10.1523/jneurosci.6472-10.2011
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发表时间：
2011-04-06
影响因子：
5.3
通讯作者：
Medendorp, W. Pieter
中科院分区：
文献类型：
--
作者：
Clemens, Ivar A. H.;De Vrijer, Maaike;Medendorp, W. Pieter
大多数证据表明，大脑使用贝叶斯推理，以最佳方式整合嘈杂的感觉信号已经获得了显示，在每一个模态的噪声水平分别可以预测在组合条件下的性能。当各种信号不能被孤立地测量时，这种向前的方法很难实现，如在空间定向中，这涉及视觉、体感和前庭线索的处理。相反，我们采用了逆概率方法，基于最优观测器理论。我们的目标是调查是否感知差异时发现探测两个不同的状态-身体在空间和头部在空间的方向-可以调和的共享计划，使用所有可用的感觉信号。使用心理测量方法，对7名人类受试者在倾斜< 120度时的两种取向估计进行测试：身体倾斜感知[主观身体倾斜（SBT）]和视觉垂直感知[主观视觉垂直（SVV）]。在所有受试者中，SBT比SVV更准确，SVV在倾斜角度超过60度时显示出显著的系统误差。在这两项任务中，变异性随倾斜角度增加，但在SVV中始终较低。感觉整合模型非常适合这两个数据集。在另一个实验中，仰卧的受试者判断他们的头部相对于身体的方向，独立地证实了模型预测的头对身体的噪音。模型预测的基础上派生的噪声特性从各种方式也与以前发表的赤字前庭和体感患者。我们的结论是贝叶斯计算可以解释与不同任务要求相关的空间方向判断的典型差异。
Most evidence that the brain uses Bayesian inference to integrate noisy sensory signals optimally has been obtained by showing that the noise levels in each modality separately can predict performance in combined conditions. Such a forward approach is difficult to implement when the various signals cannot be measured in isolation, as in spatial orientation, which involves the processing of visual, somatosensory, and vestibular cues. Instead, we applied an inverse probabilistic approach, based on optimal observer theory. Our goal was to investigate whether the perceptual differences found when probing two different states-body-in-space and head-in-space orientation-can be reconciled by a shared scheme using all available sensory signals. Using a psychometric approach, seven human subjects were tested on two orientation estimates at tilts < 120 degrees: perception of body tilt [subjective body tilt (SBT)] and perception of visual vertical [subjective visual vertical (SVV)]. In all subjects, the SBT was more accurate than the SVV, which showed substantial systematic errors for tilt angles beyond 60 degrees. Variability increased with tilt angle in both tasks, but was consistently lower in the SVV. The sensory integration model fitted both datasets very nicely. A further experiment, in which supine subjects judged their head orientation relative to the body, independently confirmed the predicted head-on-body noise by the model. Model predictions based on the derived noise properties from the various modalities were also consistent with previously published deficits in vestibular and somatosensory patients. We conclude that Bayesian computations can account for the typical differences in spatial orientation judgments associated with different task requirements.