Penhune Virginia B, Cismaru Roxana, Dorsaint-Pierre Raquel, Petitto Laura Ann, Zatorre Robert J
Concordia University, Department of Psychology, Montreal, Quebec, Canada.
Neuroimage. 2003 Oct;20(2):1215-25. doi: 10.1016/S1053-8119(03)00373-2.
The study of congenitally deaf individuals provides a unique opportunity to understand the organization and potential for reorganization of human auditory cortex. We used magnetic resonance imaging (MRI) to examine the structural organization of two auditory cortical regions, Heschl's gyrus (HG) and the planum temporale (PT), in deaf and hearing subjects. The results show preservation of cortical volume in HG and PT of deaf subjects deprived of auditory input since birth. Measurements of grey and white matter, as well as the location and extent of these regions in the deaf showed complete overlap both with matched controls and with previous samples of hearing subjects. The results of the manual volume measures were supported by findings from voxel-based morphometry analyses that showed increased grey-matter density in the left motor hand area of the deaf, but no differences between the groups in any auditory cortical region. This increased cortical density in motor cortex may be related to more active use of the dominant hand in signed languages. Most importantly, expected interhemispheric asymmetries in HG and PT thought to be related to auditory language processing were preserved in these deaf subjects. These findings suggest a strong genetic component in the development and maintenance of auditory cortical asymmetries that does not depend on auditory language experience. Preservation of cortical volume in the deaf suggests plasticity in the input and output of auditory cortex that could include language-specific or more general-purpose information from other sensory modalities.
对先天性失聪个体的研究为理解人类听觉皮层的组织及重组潜力提供了独特契机。我们使用磁共振成像（MRI）来检查失聪和听力正常受试者的两个听觉皮层区域，即颞横回（HG）和颞平面（PT）的结构组织。结果显示，自出生起就丧失听觉输入的失聪受试者的HG和PT区域的皮层体积得以保留。对失聪者灰质和白质的测量，以及这些区域的位置和范围，显示与匹配的对照组以及先前听力正常受试者的样本完全重叠。手动体积测量结果得到基于体素的形态学分析结果的支持，该分析表明失聪者左运动手区的灰质密度增加，但两组在任何听觉皮层区域均无差异。运动皮层中这种增加的皮层密度可能与在手语中更多地主动使用优势手有关。最重要的是，这些失聪受试者保留了HG和PT中被认为与听觉语言处理相关的预期半球间不对称性。这些发现表明，听觉皮层不对称性的发展和维持存在强大的遗传成分，且不依赖于听觉语言经验。失聪者皮层体积的保留表明听觉皮层的输入和输出具有可塑性，这可能包括来自其他感觉模态的特定语言或更通用的信息。
