Aging & Cognition Research Group, German Center for Neurodegenerative Diseases (DZNE), 39120, Magdeburg, Germany.
Center for Behavioral Brain Sciences (CBBS), 39118, Magdeburg, Germany.
Sci Rep. 2019 Feb 25;9(1):2663. doi: 10.1038/s41598-019-39270-7.
The internal representation of the body emerges via the integration of multisensory body cues. Sensory signal transfer and the ability to integrate multisensory information deteriorate significantly with increasing age. However, there is little empirical evidence on age-related changes in body representations based on multisensory integration. Here, we used a standard paradigm for evaluating body representations based on multisensory integration, the rubber hand illusion, and compared the amount of proprioceptive drift and changes in perceived body ownership triggered by the integration of visual, tactile, and proprioceptive cues between younger and older adults. To account for potential age-related differences in the temporal stability of the illusion, proprioceptive drift was measured at five different time points. Our results show that older adults used synchronous visuo-tactile cues similarly to younger adults to update both the position of their own hand, and their feeling of ownership over the artificial hand. Independent of visuo-tactile synchrony, older adults perceived their hand as closer to their body than younger adults did, and showed a less stable representation of this in-depth hand position. This proprioceptive bias towards the body did not correlate with the strength of the illusion. Our results indicate that the integration of visual and tactile cues is largely preserved in advanced age when used to update limb position, whereas proprioception worsens with age. This may be linked to two different pathways that underlie changes in body representations over the life span.
身体的内部表示是通过多感觉线索的整合而出现的。随着年龄的增长，感觉信号的传递和整合多感觉信息的能力会显著下降。然而，基于多感觉整合的身体表示的年龄相关性变化的实证证据很少。在这里，我们使用了一种基于多感觉整合的身体表示评估的标准范式，即橡胶手错觉，并比较了年轻和年长成年人在整合视觉、触觉和本体感觉线索时触发的本体感觉漂移和感知身体所有权变化的程度。为了说明错觉的时间稳定性方面可能存在的年龄相关差异，在五个不同的时间点测量了本体感觉漂移。我们的结果表明，年长成年人与年轻成年人一样，使用同步的视触线索来更新自己的手的位置和对人造手的所有权感。独立于视触同步，年长成年人感知到他们的手比年轻成年人更接近他们的身体，并且对这种深入的手部位置的表示不太稳定。这种对身体的本体感觉偏差与错觉的强度无关。我们的结果表明，当用于更新肢体位置时，视觉和触觉线索的整合在高龄时基本保持不变，而本体感觉会随着年龄的增长而恶化。这可能与贯穿整个生命周期的身体表示变化的两种不同途径有关。
