Laboratory of Clinical Biochemistry and Molecular Biology, Department of Surgery, Medical, Molecular Pathology, and Critical Care, University of Pisa, Pisa, Italy.
Laboratory of Clinical Biochemistry and Molecular Biology, Department of Surgery, Medical, Molecular Pathology, and Critical Care, University of Pisa, Pisa, Italy; MRI Lab, Fondazione "G. Monasterio" Regione Toscana/C.N.R., Pisa, Italy.
Neuropsychologia. 2015 Feb;68:59-70. doi: 10.1016/j.neuropsychologia.2015.01.004. Epub 2015 Jan 6.
Although vision offers distinctive information to space representation, individuals who lack vision since birth often show perceptual and representational skills comparable to those found in sighted individuals. However, congenitally blind individuals may result in impaired spatial analysis, when engaging in 'visual' spatial features (e.g., perspective or angle representation) or complex spatial mental abilities. In the present study, we measured behavioral and brain responses using functional magnetic resonance imaging in sighted and congenitally blind individuals during spatial imagery based on a modified version of the mental clock task (e.g., angle discrimination) and a simple recognition control condition, as conveyed across distinct sensory modalities: visual (sighted individuals only), tactile and auditory. Blind individuals were significantly less accurate during the auditory task, but comparable-to-sighted during the tactile task. As expected, both groups showed common neural activations in intraparietal and superior parietal regions across visual and non-visual spatial perception and imagery conditions, indicating the more abstract, sensory independent functional organization of these cortical areas, a property that we named supramodality. At the same time, however, comparisons in brain responses and functional connectivity patterns across experimental conditions demonstrated also a functional lateralization, in a way that correlated with the distinct behavioral performance in blind and sighted individuals. Specifically, blind individuals relied more on right parietal regions, mainly in the tactile and less in the auditory spatial processing. In sighted, spatial representation across modalities relied more on left parietal regions. In conclusions, intraparietal and superior parietal regions subserve supramodal spatial representations in sighted and congenitally blind individuals. Differences in their recruitment across non-visual spatial processing in sighted and blind individuals may be related to distinctive behavioral performance and/or mental strategies adopted when they deal with the same spatial representation as conveyed through different sensory modalities.
尽管视觉为空间表示提供了独特的信息，但从出生就失明的个体通常表现出与视力正常个体相当的知觉和表示技能。然而，先天性失明个体在从事“视觉”空间特征（例如，透视或角度表示）或复杂的空间心理能力时，可能会导致空间分析受损。在本研究中，我们使用功能磁共振成像测量了视力正常和先天性失明个体在基于心理时钟任务（例如，角度辨别）的空间想象以及简单识别控制条件下的行为和大脑反应，这些任务通过不同的感觉模态传达：视觉（仅视力正常个体）、触觉和听觉。在听觉任务中，失明个体的准确性明显较低，但在触觉任务中与视力正常个体相当。正如预期的那样，两组在顶内和顶叶上区都表现出共同的神经激活，这些区域跨越了视觉和非视觉的空间感知和想象条件，表明这些皮质区域具有更抽象、感觉独立的功能组织，我们称之为超模式。然而，同时，对大脑反应和功能连接模式的比较也表明了功能的偏侧化，这种偏侧化与失明和视力正常个体的不同行为表现相关。具体来说，失明个体更多地依赖于右侧顶叶区域，主要是在触觉中，而在听觉空间处理中较少。在视力正常个体中，跨模态的空间表示更多地依赖于左侧顶叶区域。总之，顶内和顶叶上区为视力正常和先天性失明个体提供了超模式的空间表示。在视力正常和失明个体中，非视觉空间处理过程中对它们的招募存在差异，这可能与他们在处理通过不同感觉模态传达的相同空间表示时所采用的独特行为表现和/或心理策略有关。
