Barton Jason J S, Malcolm George L, Hefter Rebecca L
Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston Massachusetts, USA.
J Neuroophthalmol. 2007 Dec;27(4):268-74. doi: 10.1097/WNO.0b013e31815b9b85.
Spatial analysis may be subdivided into between-object and within-object spatial coding. We investigated the contribution of various visual cues to grouping processes that might determine whether single or multiple objects were perceived and therefore which type of spatial coding would be used for a stimulus.
We asked three patients to make shape judgments with a series of displays showing triangular arrangements, moving from more implicit triangles defined by separate objects at the apices (between-object spatial coding) to more explicit triangles with line edges or surface texture (within-object spatial coding).
In two patients with prosopagnosia, within-object spatial judgments were impaired, whereas between-object spatial judgments were normal. In a patient with Bálint syndrome, the reverse pattern was obtained. Surface texture but not outline closure led to mandatory within-object coding in the prosopagnosic patients, whereas outline or surface texture was sufficient to support intact within-object spatial judgments in the patient with Bálint syndrome. Illusory contours were ineffective in promoting within-object coding in either condition.
These findings support the existence of parallel representations of space for within-object and between-object processing and reveal the efficacy of different cues in determining which representation is potentially accessible.
空间分析可细分为物体间和物体内空间编码。我们研究了各种视觉线索对分组过程的贡献，这些分组过程可能决定是感知单个物体还是多个物体，从而决定对刺激使用哪种空间编码类型。
我们让三名患者对一系列显示三角形排列的图像进行形状判断，从由顶点处单独物体定义的更隐含三角形（物体间空间编码）到具有线条边缘或表面纹理的更明确三角形（物体内空间编码）。
在两名面孔失认症患者中，物体内空间判断受损，而物体间空间判断正常。在一名患有巴林特综合征的患者中，得到了相反的模式。表面纹理而非轮廓闭合导致面孔失认症患者进行强制性物体内编码，而轮廓或表面纹理足以支持巴林特综合征患者完整的物体内空间判断。在两种情况下，虚幻轮廓在促进物体内编码方面均无效。
这些发现支持物体内和物体间处理存在空间的并行表征，并揭示了不同线索在确定哪些表征可能可用方面的功效。
