Neuropsychological evidence of an integrated visuotactile representation of peripersonal space in humans
Neuropsychological evidence of an integrated visuotactile representation of peripersonal space in humans
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DOI：
10.1162/089892998562988
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发表时间：
1998-09-01
影响因子：
3.2
通讯作者：
Zeloni, G
中科院分区：
文献类型：
--
作者：
Làdavas, E;di Pellegrino, G;Zeloni, G
目前对灭绝的解释表明，这种疾病是由于同侧和对侧空间表征之间的不平衡竞争造成的。本研究解决的问题是，一种感觉模态（即触觉）中左右空间表征之间的竞争是否可以通过激活与受损表征（即视觉）功能相关的不同模态中完整的空间表征来减少或加剧。这一假设在 10 名右半球受损的患者身上得到了检验，这些患者均遭受了可靠的触觉消退。我们发现，患者同侧手（即视觉周围空间）附近出现的视觉刺激会抑制对侧手上传递的触觉刺激（跨模态视觉触觉消退），其程度与同侧触觉刺激（单模态触觉消退）相同。研究还发现，对侧手附近出现的视觉刺激可以改善对同一只手施加的触觉刺激的检测。与此形成鲜明对比的是，当视觉刺激远离患者手部周围的空间（即个人外空间）时，观察到视觉对触觉感知的调节作用较小。这项研究清楚地证明了以人类手部为中心的视觉周围空间的存在及其对触觉感知的调节作用。这些发现是通过参考猕猴前运动皮层和顶叶皮层中双峰神经元的活动来解释的，这些神经元在手上具有触觉感受域，并且在紧邻触觉域的空间中具有相应的视觉感受域。
Current interpretations of extinction suggest that the disorder is due to an unbalanced competition between ipsilesional and contralesional representations of space.The question addressed in this study is whether the competition between left and right representations of space in one sensory modality (i.e., touch) can be reduced or exacerbated by the activation of an intact spatial representation in a different modality that is functionally linked to the damaged representation (i.e., vision). This hypothesis was tested in 10 right-hemisphere lesioned patients who suffered from reliable tactile extinction. We found that a visual stimulus presented near the patient's ipsilesional hand (i.e., visual peripersonal space) inhibited the processing of a tactile stimulus delivered on the contralesional hand (cross-modal visuotactile extinction) to the same extent as did an ipsilesional tactile stimulation (unimodal tactile extinction). It was also found that a visual stimulus presented near the contralesional hand improved the detection of a tactile stimulus applied to the same hand. In striking contrast, less modulatory effects of vision on touch perception were observed when a visual stimulus was presented far from the space immediately around the patient's hand (i.e., extrapersonal space).This study clearly demonstrates the existence of a visual peripersonal space centered on the hand in humans and its modulatory effects on tactile perception. These findings are explained by referring to the activity of bimodal neurons in premotor and parietal cortex of macaque, which have tactile receptive fields on the hand and corresponding visual receptive fields in the space immediately adjacent to the tactile fields.