Kahrimanovic Mirela, Bergmann Tiest Wouter M, Kappers Astrid M L
Physics of Man, Universiteit Utrecht, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
Exp Brain Res. 2009 Apr;194(2):287-97. doi: 10.1007/s00221-008-1697-x. Epub 2009 Jan 21.
The influence of temporal and spatial context during haptic roughness perception was investigated in two experiments. Subjects examined embossed dot patterns of varying average dot distance. A two-alternative forced-choice procedure was used to measure discrimination thresholds and biases. In Experiment 1, subjects had to discriminate between two stimuli that were presented simultaneously to adjacent fingers, after adaptation of one of these fingers. The results showed that adaptation to a rough surface decreased the perceived roughness of a surface subsequently scanned with the adapted finger, whereas adaptation to a smooth surface increased the perceived roughness (i.e. contrast after effect). In Experiment 2, subjects discriminated between subsequent test stimuli, while the adjacent finger was stimulated simultaneously. The results showed that perceived roughness of the test stimulus shifted towards the roughness of the adjacent stimulus (i.e. assimilation effect). These contextual effects are explained by structures of cortical receptive fields. Analogies with comparable effects in the visual system are discussed.
在两项实验中研究了触觉粗糙度感知过程中时间和空间背景的影响。受试者检查了平均点距不同的压纹点图案。采用二选一强制选择程序来测量辨别阈值和偏差。在实验1中，在其中一根手指适应后，受试者必须辨别同时呈现给相邻手指的两种刺激。结果表明，对粗糙表面的适应会降低随后用适应手指扫描的表面的感知粗糙度，而对光滑表面的适应会增加感知粗糙度（即对比后效应）。在实验2中，受试者辨别后续的测试刺激，同时相邻手指受到刺激。结果表明，测试刺激的感知粗糙度向相邻刺激的粗糙度偏移（即同化效应）。这些背景效应由皮质感受野的结构来解释。文中还讨论了与视觉系统中类似效应的类比。
