fMRI Studies of the Visual System in Deaf Individuals

描述(申请人提供)：尽管可塑性是人类神经系统的基本属性，但不同皮质区域可修改的特异性以及在什么情况下尚不清楚。先天性耳聋和早期习得美国手语(ASL)为探索由于感觉体验改变而导致的经验依赖性变化提供了独特的机会。关于这类人群运动加工的背侧视觉处理通路的功能解剖学变化已有报道，但缺乏对腹侧通路的研究。聋人手语者主要依靠视觉进行交流，与听力正常的人相比，他们对面部暗示的依赖程度不成比例。在缺乏听觉线索的情况下，聋人必须从别人的脸上获取情感和语言信息，并注意到ASL特有的语言面部表情。行为数据表明，与听力不好的人相比，聋人和听力正常的人具有面部加工优势，但这些影响的神经轨迹尚不清楚。这项研究使用功能磁共振成像来研究背侧和腹侧视觉通路功能的经验依赖性变化。聋人手语者、听力手语者和听力非手语者将在注意空间位置或物体识别时使用相同的刺激进行扫描。定位任务将确定运动处理的功能重组是否适用于其他背侧通路功能，而客体任务，包括面孔和非面孔对象，将决定腹侧通路是否发生类似的重组，以及它是特定于面孔还是概括到其他对象类别。听觉剥夺和ASL习得引起的改变可能包括空间和物体知觉/网络的可塑性，以及听觉皮质的重新招募以进行视觉处理。

DESCRIPTION (provided by applicant): Although plasticity is a fundamental property of the human nervous system, the specificity with which different cortical regions are modifiable, and under what circumstances, is not yet known. Congenital deafness and early acquisition of American Sign Language (ASL) provide a unique opportunity to explore experience-dependent changes due to altered sensory experience. Changes in the functional anatomy of the dorsal visual processing pathway have been reported for such populations for motion processing, but studies of the ventral pathway are lacking. Deaf signers rely predominantly on vision for communication, and are disproportionately dependent on facial cues compared to hearing individuals. Lacking auditory cues, the deaf must garner both affective and linguistic information from others' faces and attend to linguistic facial expressions unique to ASL. Behavioral data indicate a face processing advantage for native deaf and hearing signers, compared to hearing non-signers, yet the neural locus of these effects is unknown. This study uses fMRI to investigate experience-dependent changes in dorsal and ventral visual pathway functions. Deaf signers, hearing signers, and hearing non-signers will be scanned while attending to spatial location or object identity using identical stimuli. The location task will determine if functional reorganization reported for motion processing generalizes to other dorsal pathway functions, and the object task, including both faces and a non-face object, will determine whether analogous reorganization occurs in the ventral pathway, and if it is specific to faces or generalizes to other object categories. Changes due to auditory deprivation and ASL acquisition may include plasticity of the spatial and object perception/ networks, and recruitment of auditory cortex for visual processing.