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Adaptation to Unilateral Hearing Loss in Humans: Cortical and Perceptual Effects

对人类单侧听力损失的适应：皮质和知觉影响

基本信息

批准号：
7334714
负责人：
PETER C GORDON
金额：
$ 17.84万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-01-01 至 2010-12-31
项目状态：
已结题

项目摘要

The goal of this project is to increase understanding of adaptation in human auditory cortex after peripheral hearing loss in adults. Two types of cortical adaptation have been studied for hearing: expansion of cortical representation for the frequency that is at the edge of a sharply-sloping hearing loss and a reduction in the usual pattern of cortical lateralization (more contralateralthan ipsilateral activity) in cases of unilateral deafness. We have used functional magnetic resonance imaging (fMRI) and psychoacoustictasks to investigate the relationship between cortical adaptation and perceptual ability in two individuals with a sloping hearing loss in one ear and normal hearing in the other ear. Both individuals showed reduced lateralization of activity in auditory cortex in response to sounds heard in their normal ear as compared to their impaired ear. Reduced lateralization after stimulation of the normal ear was attributable to an increase in ipsilateral cortical activation and was observed both at frequencies where hearing was absent in the impaired ear and also where it was fully preserved as indicated by audiometric criteria. Evidence of perceptual changes in the patients that we studied was found in two binaural listening tasks where a signal was presented in one ear and a distractor sound in the other. Performance on signals presented to the impaired ear was more susceptible to interference from the normal ear than vice versa even at frequencies where audiometric sensitivity in the two ears was equivalent. Together, the fMRI results and psychoacoustic results provide a compelling parallel between cortical adaptation and perceptual function in adult humans. This project uses fMRI to determine further the nature and extent of long-term neural adaptation in individuals with unilateral hearing impairment, and psychoacoustic experiments to determine the nature of the perceptual changes that are associatedwith corticaladaptation. Increased understanding of long-term cortical adaptation to sensory loss has the potential to provide insight into how processes of learning are constrained both by patterns of neural connectivity created during development and by the limitations on neural growth in mature animals. Increased understanding of cortical adaptation also has the potential to shed light on how higher-level neural processes influence the benefits and limitations of interventions that restore (or partially restore) lost sensory input.

这个项目的目标是增加对人类听觉皮层在外周神经损伤后的适应性的理解。成人听力损失两种类型的皮层适应已被研究的听力：皮层的扩张，表示处于急剧倾斜听力损失边缘的频率和听力损失的降低单侧皮质偏侧的常见模式（对侧活动多于同侧活动）耳聋我们使用功能性磁共振成像（fMRI）和心理声学任务，研究两个患有脑卒中的个体的皮层适应和知觉能力之间的关系。一只耳朵听力下降，另一只耳朵听力正常。两个人都表现出减少听觉皮层对正常耳朵听到的声音的反应的偏侧化，受损的耳朵刺激正常耳后偏侧化减少归因于在同侧皮层激活，并观察到在听力缺席的频率，受损的耳朵，以及听力标准所示的完全保存的耳朵。的证据我们研究的患者的感知变化是在两个双耳听力任务中发现的，在一只耳朵中呈现，在另一只耳朵中呈现干扰音。信号性能提交给受损耳朵更容易受到干扰，从正常耳朵比反之亦然，即使在频率其中两只耳朵的听力灵敏度相等。总之，功能磁共振成像结果和心理声学的结果提供了一个令人信服的平行皮质适应和知觉功能，成年人该项目使用功能磁共振成像来进一步确定长期神经功能障碍的性质和程度。单侧听力障碍患者的适应性，以及心理声学实验，以确定 the nature性质of the perceptual知觉changes变化that are associated关联with corticaladaptation适应. 增加对感觉丧失的长期皮层适应的理解有可能提供洞察力学习过程是如何受到神经连接模式的限制，发育和成熟动物神经生长的限制。增加对皮质的了解适应也有可能揭示更高层次的神经过程如何影响这些好处以及恢复（或部分恢复）失去的感觉输入的干预措施的局限性。