Department of Psychology, University of California, San Diego, United States.
Brain Cogn. 2013 Jun;82(1):117-26. doi: 10.1016/j.bandc.2013.01.006. Epub 2013 Feb 28.
Previous studies have asked whether visual sensitivity and attentional processing in deaf signers are enhanced or altered as a result of their different sensory experiences during development, i.e., auditory deprivation and exposure to a visual language. In particular, deaf and hearing signers have been shown to exhibit a right visual field/left hemisphere advantage for motion processing, while hearing nonsigners do not. To examine whether this finding extends to other aspects of visual processing, we compared deaf signers and hearing nonsigners on motion, form, and brightness discrimination tasks. Secondly, to examine whether hemispheric lateralities are affected by attention, we employed a dual-task paradigm to measure form and motion thresholds under "full" vs. "poor" attention conditions. Deaf signers, but not hearing nonsigners, exhibited a right visual field advantage for motion processing. This effect was also seen for form processing and not for the brightness task. Moreover, no group differences were observed in attentional effects, and the motion and form visual field asymmetries were not modulated by attention, suggesting they occur at early levels of sensory processing. In sum, the results show that processing of motion and form, believed to be mediated by dorsal and ventral visual pathways, respectively, are left-hemisphere dominant in deaf signers.
先前的研究曾探讨过聋人手语使用者在其发育过程中因不同的感官体验（即听觉剥夺和接触视觉语言）而导致的视觉敏感性和注意力处理是否得到增强或改变。具体而言，已发现聋人手语使用者和听力非手语使用者在运动处理方面表现出右视野/左半球优势，而听力非手语使用者则没有。为了研究这一发现是否扩展到其他视觉处理方面，我们比较了聋人手语使用者和听力非手语使用者在运动、形状和亮度辨别任务上的表现。其次，为了研究半球侧化是否受注意力影响，我们采用了双重任务范式，在“充分”和“较差”注意力条件下测量形状和运动阈值。聋人手语使用者而非听力非手语使用者在运动处理方面表现出右视野优势。这种效应也出现在形状处理中，而不是亮度任务中。此外，在注意力效应方面没有观察到组间差异，并且运动和形状视野不对称不受注意力调节，这表明它们发生在感觉处理的早期水平。总之，研究结果表明，被认为分别由背侧和腹侧视觉通路介导的运动和形状处理在聋人手语使用者中是左半球优势的。
