Department of Psychology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Neuropsychologia. 2019 Oct;133:107154. doi: 10.1016/j.neuropsychologia.2019.107154. Epub 2019 Aug 6.
Research has shown that damage to either the left or right hemisphere can lead to deficits in visuoconstructional skills including drawing and figure copying. Nevertheless, research would suggest that the nature of the deficits arising from left and right brain injury are distinct in nature if not severity, with the right hemisphere, and parietal cortex specifically, seen as critical for obtaining accurate spatial relations and the left hemisphere important for effective organisation (i.e., executive function). Much of this work on drawing and figure copying following brain damage has rested on qualitative assessments or crude marking scales with descriptive anchors for what constitutes good or poor performance. We employed quantitative analyses of drawings developed to assess accuracy in novice and expert artists. We analyzed drawings of a cube and a star in 50 patients (23, left brain damaged: LBD; 27 right brain damaged: RBD) who had suffered strokes. Our analysis was sensitive to the presence of neglect on the cube (i.e., missing left sided details) with voxel-wise lesion symptom mapping (VLSM) highlighting involvement of expected brain regions (superior temporal and supramarginal gyri). With left-sided omissions removed from analyses, we failed to find any difference between LBD and RBD patients. While the presence of left neglect appeared to exaggerate errors, this was only significant for errors of scale and proportion for the star drawing. VLSM of the distinct error domains demonstrated white matter involvement (and a minor contribution from the right insula) with respect to scale errors of the cube only. Finally, blinded judgements of hemisphere of lesion based on qualitative assessment of the drawings were no better than chance. These results suggest that figure copying is a complex task relying on large scale neural networks involving both hemispheres. Clearly, models of visuoconstructional capacity that emphasise right hemisphere dominance are not entirely accurate.
研究表明，左半球或右半球的损伤都会导致视空间建构技能的缺陷，包括绘画和图形临摹。然而，如果不考虑严重程度，研究表明，左脑和右脑损伤引起的缺陷性质是不同的，右脑，特别是顶叶皮层，被认为对获得准确的空间关系至关重要，而左半球对有效组织（即执行功能）很重要。脑损伤后关于绘画和图形临摹的大部分研究都依赖于定性评估或粗略的标记量表，用描述性锚点来表示良好或较差的表现。我们采用了为评估新手和专家艺术家的准确性而开发的定量分析方法来分析绘画。我们分析了 50 名中风患者（23 名左脑损伤：LBD；27 名右脑损伤：RBD）的立方体和五角星的绘画。我们的分析对立方体贴图上的忽视（即左侧细节缺失）很敏感，体素病变症状映射（VLSM）突出了预期大脑区域（颞上回和缘上回）的参与。从分析中去除左侧遗漏后，我们发现 LBD 和 RBD 患者之间没有任何差异。虽然左侧忽视的存在似乎会夸大错误，但这仅对五角星的比例和大小错误有显著影响。不同错误域的 VLSM 显示了白质的参与（以及右岛叶的少量贡献），仅与立方体的比例错误有关。最后，基于对绘图的定性评估，对病变半球进行的盲法判断并不比随机猜测好。这些结果表明，图形临摹是一项复杂的任务，依赖于涉及两个半球的大规模神经网络。显然，强调右脑优势的视空间建构能力模型并不完全准确。
