Multisensory Integration Laboratory, Centre for Vision Research, York University, 4700 Keele Street, Toronto, ON, Canada, M3J 1P3.
Neuroscience. 2010 Jun 2;167(4):1138-50. doi: 10.1016/j.neuroscience.2010.02.065. Epub 2010 Mar 4.
Perception of the relative orientation of the self and objects in the environment requires integration of visual and vestibular sensory information, and an internal representation of the body's orientation. Parkinson's disease (PD) patients are more visually dependent than controls, implicating the basal ganglia in using visual orientation cues. We examined the relative roles of visual and non-visual cues to orientation in PD using two different measures: the subjective visual vertical (SVV) and the perceptual upright (PU). We tested twelve PD patients (nine both on- and off-medication), and thirteen age-matched controls. Visual, vestibular and body cues were manipulated using a polarized visual room presented in various orientations while observers were upright or lying right-side-down. Relative to age-matched controls, patients with PD showed more influence of visual cues for the SVV but were more influenced by the direction of gravity for the PU. Increased SVV visual dependence corresponded with equal decreases of the contributions of body sense and gravity. Increased PU gravitational dependence corresponded mainly with a decreased contribution of body sense. Curiously however, both of these effects were significant only when patients were medicated. Increased SVV visual dependence was highest for PD patients with left-side initial motor symptoms. PD patients when on and off medication were more variable than controls when making judgments. Our results suggest that (i) PD patients are not more visually dependent in general, rather increased visual dependence is task specific and varies with initial onset side, (ii) PD patients may rely more on vestibular information for some perceptual tasks which is reflected in relying less on the internal representation of the body, and (iii) these effects are only present when PD patients are taking dopaminergic medication.
自我和环境中物体的相对方向感知需要整合视觉和前庭感觉信息，以及身体方向的内部表示。帕金森病（PD）患者比对照组更依赖视觉，这暗示基底神经节在使用视觉方向线索。我们使用两种不同的测量方法来检查视觉和非视觉线索对 PD 中的定向的相对作用：主观视觉垂直（SVV）和感知垂直（PU）。我们测试了 12 名 PD 患者（9 名正在服用药物和 3 名未服用药物）和 13 名年龄匹配的对照组。通过呈现各种定向的偏振视觉房间来操纵视觉、前庭和身体线索，而观察者处于直立或右侧卧位。与年龄匹配的对照组相比，PD 患者的 SVV 受视觉线索的影响更大，但对于 PU 则受重力方向的影响更大。SVV 视觉依赖性增加与身体感觉和重力的贡献相等减少相对应。PU 重力依赖性增加主要与身体感觉贡献减少相对应。然而，有趣的是，这些影响仅在患者服用药物时才显著。对于初始运动症状位于左侧的 PD 患者，SVV 视觉依赖性增加最高。服用和未服用药物的 PD 患者在进行判断时比对照组更具变异性。我们的结果表明：（i）PD 患者总体上并不更依赖视觉，而是增加的视觉依赖性是特定任务的，并且随着初始发病侧的不同而变化；（ii）PD 患者在某些感知任务中可能更依赖前庭信息，这反映在他们对身体内部表示的依赖减少；（iii）这些影响仅在 PD 患者服用多巴胺能药物时才存在。
