Mira Institute for Biomedical Technology and Technical Medicine, Biomedical Signals and Systems, University of Twente, Zuidhorst Room ZH211, Drienerlolaan 5, Postbus 217, Enschede, The Netherlands,
Exp Brain Res. 2014 Feb;232(2):597-607. doi: 10.1007/s00221-013-3768-x. Epub 2013 Dec 12.
Few experimental data are available about the influence of stimulus intensity on localization of cutaneous stimuli. The localization behavior of an individual as function of the veridical stimulus sites can be represented in the form of a perceptual map. It is unknown how the intensity of cutaneous stimuli influences these perceptual maps. We investigated the effect of stimulus intensity on trial-to-trial localization variability and on perceptual maps. We applied non-painful electrocutaneous stimuli of three different intensities through seven surface electrodes on the lower arm of healthy participants. They localized the stimuli on a tablet monitor mounted directly above their arm, on which a photograph of this arm was presented. The length of the arm over which the stimuli were localized was contracted when compared to the real electrode positions. This length increased toward veridical with increasing stimulus intensity. The trial-to-trial variance of the localizations dropped significantly with increasing intensity. Furthermore, localization biases of individual stimulus positions were shown to decrease with increasing stimulus intensity. We conclude that tactile stimuli are localized closer to veridical with increasing intensity in two respects: the localizations become more consistent and more accurate.
关于刺激强度对皮肤刺激定位的影响，目前仅有少量实验数据。个体的定位行为作为真实刺激部位的函数，可以用感知图的形式表示。目前还不清楚皮肤刺激的强度如何影响这些感知图。我们研究了刺激强度对试验间定位变异性和感知图的影响。我们通过七个表面电极在手臂下部施加三种不同强度的非疼痛电皮肤刺激，参与者在直接置于手臂上方的平板电脑监视器上定位刺激，手臂的照片显示在监视器上。与真实电极位置相比，被定位的刺激区域的手臂长度被缩短。随着刺激强度的增加，这个长度向真实电极位置靠拢。随着强度的增加，定位的试验间变异性显著下降。此外，随着刺激强度的增加，个体刺激位置的定位偏差也显示出减小的趋势。我们得出结论，从两个方面来看，随着刺激强度的增加，触觉刺激的定位会更接近真实：定位变得更加一致和准确。
