Thomas Richard, Forde Emer
Institute of Cognitive Neuroscience, University College London, London, UK.
Neuropsychologia. 2006;44(6):982-6. doi: 10.1016/j.neuropsychologia.2005.09.005. Epub 2005 Oct 25.
We report a study on a patient (DW) with integrative visual agnosia and a category-specific recognition impairment for living things. We assessed DW's local and global processing and tested if his integrative agnosia could have led directly to his category-specific impairment. The main findings were: (i) DW was faster at identifying local compared to global letters. (ii) DW showed no local-to-global (or global-to-local) interference effects in selective attention tasks. (iii) DW showed a congruency effect in a divided attention task, suggesting that, when his attention was cued to both levels, he could process information simultaneously and integrate local and global information. (iv) Controls were poorer at naming nonliving compared to living things when presented with silhouettes. These data suggest that local and global information are differentially weighted in the visual recognition of living and nonliving things, and that an impairment in processing the overall shape of an object can lead to a category-specific deficit for living things. Crucially, this implies that category-specific impairments do not necessarily reflect damage to the semantic system, and models of semantic memory based on this assumption need to be revised.
我们报告了一项针对患有整合性视觉失认症且对生物存在类别特异性识别障碍的患者（DW）的研究。我们评估了DW的局部和整体加工能力，并测试了他的整合性失认症是否可能直接导致了他的类别特异性障碍。主要研究结果如下：（i）与识别整体字母相比，DW识别局部字母的速度更快。（ii）在选择性注意任务中，DW未表现出局部到整体（或整体到局部）的干扰效应。（iii）在分心任务中，DW表现出一致性效应，这表明，当他的注意力同时指向两个水平时，他能够同时处理信息并整合局部和整体信息。（iv）当呈现轮廓时，对照组在命名无生命物体方面比命名有生命物体表现更差。这些数据表明，在对有生命和无生命物体的视觉识别中，局部和整体信息的权重不同，并且处理物体整体形状的损伤可能导致对生物的类别特异性缺陷。至关重要的是，这意味着类别特异性障碍不一定反映语义系统的损伤，基于这一假设的语义记忆模型需要修订。
