Bellan Valeria, Gilpin Helen R, Stanton Tasha R, Dagsdóttir Lilja K, Gallace Alberto, Lorimer Moseley G
Body in Mind Research Group - The Sansom Institute for Health Research Adelaide, University of South Australia, GPO Box 2471, Adelaide, 5001, Australia.
PainAdelaide, Adelaide, Australia.
Exp Brain Res. 2017 Feb;235(2):447-455. doi: 10.1007/s00221-016-4782-6. Epub 2016 Oct 24.
When vision and proprioception are rendered incongruent during a hand localisation task, vision is initially weighted more than proprioception in determining location, and proprioception gains more weighting over time. However, it is not known whether, under these incongruency conditions, particular areas of space are also weighted more heavily than others, nor whether explicit knowledge of the sensory incongruence (i.e. disconfirming the perceived location of the hand) modulates the effect. Here, we hypothesised that both non-informative inputs coming from one side of space and explicit knowledge of sensory incongruence would modulate perceived location of the limb. Specifically, we expected spatial weighting to shift hand localisation towards the weighted area of space, and we expected greater weighting of proprioceptive input once perceived location was demonstrated to be inaccurate. We manipulated spatial weighting using an established auditory cueing paradigm (Experiment 1, n = 18) and sensory incongruence using the 'disappearing hand trick' (Experiment 2, n = 9). Our first hypothesis was not supported-spatial weighting did not modulate hand localisation. Our second hypothesis was only partially supported-disconfirmation of hand position did lead to more accurate localisations, even if participants were still unaware of their hand position. This raised the possibility that rather than disconfirmation, a simple movement of the hand in view could update the sensory-motor system, by immediately increasing the weighting of proprioceptive input relative to visual input. This third hypothesis was then confirmed (Experiment 3, n = 9). These results suggest that hand localisation is robust in the face of differential weighting of space, but open to modulation in a modality-specific manner, when one sense (vision) is rendered inaccurate.
在手定位任务中，当视觉和本体感觉呈现不一致时，在确定位置方面，视觉最初比本体感觉的权重更大，且随着时间推移本体感觉的权重会增加。然而，尚不清楚在这些不一致的条件下，空间的特定区域是否也比其他区域的权重更大，也不清楚对感觉不一致的明确认知（即否定手部的感知位置）是否会调节这种效应。在此，我们假设来自空间一侧的非信息性输入以及对感觉不一致的明确认知都会调节肢体的感知位置。具体而言，我们预期空间权重会使手的定位向空间的加权区域偏移，并且一旦证明感知位置不准确，我们预期本体感觉输入的权重会更大。我们使用既定的听觉提示范式来操纵空间权重（实验1，n = 18），并使用“消失的手技巧”来操纵感觉不一致（实验2，n = 9）。我们的第一个假设未得到支持——空间权重并未调节手的定位。我们的第二个假设仅得到部分支持——对手部位置的否定确实导致了更准确的定位，即使参与者仍然不知道他们手部的位置。这就提出了一种可能性，即不是否定，而是手部在视野中的简单移动可以通过立即增加本体感觉输入相对于视觉输入的权重来更新感觉运动系统。然后这第三个假设得到了证实（实验3，n = 9）。这些结果表明，面对空间的差异加权时，手的定位是稳健的，但当一种感觉（视觉）变得不准确时，它会以特定模态的方式接受调节。
