Bellan Valeria, Gilpin Helen R, Stanton Tasha R, Newport Roger, Gallace Alberto, Moseley G Lorimer
Sansom Institute for Health Research, University of South Australia & PainAdelaide, Adelaide, 5001, Australia.
Exp Brain Res. 2015 Jun;233(6):1689-701. doi: 10.1007/s00221-015-4242-8. Epub 2015 Mar 11.
Previous studies showed that self-localisation ability involves both vision and proprioception, integrated into a single percept, with the tendency to rely more heavily on visual than proprioceptive cues. Despite the increasing evidence for the importance of vision in localising the hands, the time course of the interaction between vision and proprioception during visual occlusion remains unclear. In particular, we investigated how the brain weighs visual and proprioceptive information in hand localisation over time when the visual cues do not reflect the real position of the hand. We tested three hypotheses: Self-localisations are less accurate when vision and proprioception are incongruent; under the same conditions of incongruence, people first rely on vision and gradually revert to proprioception; if vision is removed immediately prior to hand localisation, accuracy increases. Sixteen participants viewed a video of their hands, under three conditions each undertaken with eyes open or closed: Incongruent conditions (right hand movement seen: inward, right hand real movement: outward), Congruent conditions (movement seen congruent to real movement). The right hand was then hidden from view and participants performed a localisation task whereby a moving vertical arrow was stopped when aligned with the felt position of their middle finger. A second experiment used identical methodology, but with the direction of the arrow switched. Our data showed that, in the Incongruent conditions (both with eyes open and closed), participants perceived their right hand close to its last seen position. Over time, the perceived position of the hand shifted towards the physical position. Closing the eyes before the localisation task increased the accuracy in the Incongruent condition. Crucially, Experiment 2 confirmed the findings and showed that the direction of arrow movement had no effect on hand localisation. Our hypotheses were supported: When vision and proprioception were incongruent, participants were less accurate and initially relied on vision and then proprioception over time. When vision was removed, this shift occurred more quickly. Our findings are relevant in understanding the normal and pathological processes underpinning self-localisation.
先前的研究表明，自我定位能力涉及视觉和本体感觉，二者整合为单一感知，且更倾向于严重依赖视觉而非本体感觉线索。尽管越来越多的证据表明视觉在手部定位中很重要，但在视觉遮挡期间视觉与本体感觉之间相互作用的时间进程仍不清楚。具体而言，我们研究了在视觉线索未反映手部真实位置时，大脑如何随着时间推移权衡视觉和本体感觉信息以进行手部定位。我们测试了三个假设：当视觉与本体感觉不一致时，自我定位的准确性较低；在相同的不一致条件下，人们首先依赖视觉，然后逐渐转向本体感觉；如果在手部定位前立即去除视觉，准确性会提高。16名参与者观看了他们手部的视频，在三种条件下分别睁眼或闭眼进行：不一致条件（看到右手向内移动，右手实际向外移动）、一致条件（看到的移动与实际移动一致）。然后右手被遮挡，参与者执行定位任务，即当移动的垂直箭头与他们中指的感觉位置对齐时停止。第二个实验使用相同的方法，但箭头方向相反。我们的数据表明，在不一致条件下（睁眼和闭眼），参与者将右手感知为接近其最后看到的位置。随着时间推移，手部的感知位置向实际位置移动。在定位任务前闭眼提高了不一致条件下的准确性。至关重要地，实验2证实了这些发现，并表明箭头移动方向对手部定位没有影响。我们的假设得到了支持：当视觉与本体感觉不一致时，参与者的准确性较低，最初依赖视觉后随着时间转向本体感觉。当去除视觉时，这种转变发生得更快。我们的发现对于理解自我定位的正常和病理过程具有重要意义。
