fMRI Studies of the Visual System in Deaf Individuals

描述（由申请人提供）：虽然可塑性是人类神经系统的基本特性，但不同皮层区域可改变的特异性以及在何种情况下可改变尚不清楚。先天性耳聋和早期获得美国手语（ASL）提供了一个独特的机会，探索经验依赖的变化，由于改变感官体验。已经报道了这些人群运动处理的背侧视觉处理通路的功能解剖学变化，但缺乏腹侧通路的研究。聋人主要依靠视觉进行交流，与听力正常的人相比，聋人对面部线索的依赖程度不成比例。由于缺乏听觉线索，聋人必须从他人的面部获得情感和语言信息，并注意到美国手语特有的语言面部表情。行为数据表明，与听力非签名者相比，本地聋人和听力签名者具有面部处理优势，但这些影响的神经位点尚不清楚。本研究使用功能磁共振成像研究背侧和腹侧视觉通路功能的经验依赖性变化。聋人签名者，听力签名者和听力非签名者将被扫描，同时注意到空间位置或对象身份使用相同的刺激。定位任务将确定运动处理报告的功能重组是否推广到其他背侧通路功能，而对象任务，包括面部和非面部对象，将确定腹侧通路中是否发生类似重组，以及是否特定于面部或推广到其他对象类别。由于听觉剥夺和ASL获得的变化可能包括空间和物体感知/网络的可塑性，以及听觉皮层用于视觉处理的招募。

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.