Collignon Olivier, Lassonde Maryse, Lepore Franco, Bastien Danielle, Veraart Claude
Neural Rehabilitation Engineering Laboratory, Université Catholique de Louvain, Brussels, Belgium.
Cereb Cortex. 2007 Feb;17(2):457-65. doi: 10.1093/cercor/bhj162. Epub 2006 Mar 31.
Early blind (EB) individuals can recognize bidimensional shapes using a prosthesis substituting vision with audition (PSVA) and activate right dorsal extrastriate visual cortex during the execution of this task. The present study used repetitive transcranial magnetic stimulation (rTMS) to further examine the functional role of this structure in the successful use of the PSVA. Moreover, we investigated which auditory parameter used in the prosthesis (pitch, intensity, or spatial location) might contribute to this occipital activation. Results revealed that rTMS applied to right dorsal extrastriate cortex in EB subjects interferes with both the PSVA use and the auditory spatial location task but not with pitch and intensity discriminations. By contrast, rTMS targeting the same cortical areas in sighted subjects did not affect performance on any auditory tasks. Early visual deprivation thus leads to functional cerebral cross-modal reorganization in the processing of auditory information and auditory-to-visual sensory substitution. The findings also point to the specific involvement of the dorsal visual stream for auditory spatial processing in blind subjects. Moreover, this suggests that sensory substitution prostheses can be developed using these additional neural resources to perform tasks that partially compensate for the loss of vision.
早期失明（EB）个体可以使用一种用听觉替代视觉的假体（PSVA）来识别二维形状，并且在执行该任务时激活右侧背侧纹外视觉皮层。本研究使用重复经颅磁刺激（rTMS）进一步检查该结构在成功使用PSVA中的功能作用。此外，我们研究了假体中使用的哪些听觉参数（音高、强度或空间位置）可能导致这种枕叶激活。结果显示，对EB受试者右侧背侧纹外皮层施加rTMS会干扰PSVA的使用和听觉空间定位任务，但不会干扰音高和强度辨别。相比之下，对视力正常的受试者相同皮层区域进行rTMS并不影响任何听觉任务的表现。因此，早期视觉剥夺会导致在听觉信息处理和听觉到视觉的感觉替代过程中功能性脑跨模态重组。研究结果还表明，背侧视觉通路在盲人的听觉空间处理中具有特定作用。此外，这表明可以利用这些额外的神经资源开发感觉替代假体，以执行部分补偿视力丧失的任务。
