CEREBRAL ORGANIZATION FOLLOWING COCHLEAR IMPLANT

描述(申请人提供)：植入人工耳蜗后，听觉皮质在经过一段时间的剥夺后，在建立听觉信号处理的能力方面表现出显著的可塑性。我们的长期目标是了解和定义非初级听觉皮质在人工耳蜗术后建立听觉功能的能力。这一努力需要阐明在完整(听力)状态下非初级听觉皮质对基本听觉引导行为的重要贡献，以及对先天性耳聋受试者植入人工耳蜗后非初级听觉皮质的行为能力的评估。这项应用的第一个具体目标是确定非初级听觉皮质包含处理模式知觉和空间定位的专门区域。在完整的猫身上，我们将研究前听场和后听场(分别为AAF和PAF)对模式识别和听觉空间感知的贡献。随着降温，每个区域都将被可逆地去激活，我们预计能够分别将模式识别和空间定位功能双重分离到AAF和PAF皮质。这项研究的第二个目的是确定在发育早期(2个月大)植入人工耳蜗术的先天性耳聋(CD)猫是否可以建立听觉中介行为。我们将测试动物是否能够在目标1中检查的听觉辨别、检测和定位任务中获得高水平的表现。前两个目标的结果在目标3中被结合，其中我们将结合目标2中检查的CD猫和目标1中使用的可逆去激活技术来确定早期人工耳蜗术后是否建立了非初级听觉皮质的特征正常功能地形图。为了实现这一目标，我们将在执行上述一系列听觉任务的同时，可逆地去激活植入人工耳蜗猫的AAF和PAF皮质，并将结果与AIM 1中完整猫的结果进行比较。这些研究结果将直接适用于有关幼儿人工耳蜗术后功能结果的临床情况。

DESCRIPTION (provided by applicant): Following implantation of a cochlear prosthetic, auditory cortex exhibits a remarkable plasticity in its ability to establish auditory signal processing after a period of deprivation. Our long-term goal is to understand and define the capabilities of non-primary auditory cortex to establish auditory function following cochlear implant. This endeavor requires the elucidation of the essential contributions that non-primary auditory cortex makes to fundamental aurally-guided behaviors in the intact (hearing) condition, as well as an assessment of the behavioral capabilities of non-primary auditory cortex following cochlear implant in congenitally deaf subjects. The first specific aim of this application is to determine that non-primary auditory cortex contains specialized regions for the processing of pattern perception and spatial localization. In intact cats, we will examine the contributions that the anterior and posterior auditory fields (AAF and PAF, respectively) make to pattern recognition and the perception of auditory space. Each area will be reversibly deactivated with cooling and we expect to be able to doubly-dissociate pattern discrimination and spatial localization functions to AAF and PAF cortices, respectively. The second aim in the study is to determine if congenitally deaf (CD) cats with cochlear prosthetics implanted early in development (2 months of age) can establish aurally-mediated behaviors. We will test if the animals are able to attain high performance levels on the auditory discrimination, detection, and localization tasks examined in Aim 1. The results of the first two aims are brought together in Aim 3, where we will combine the CD cats with cochlear implants examined in Aim 2 with the reversible deactivation techniques used in Aim 1 to determine if the characteristic normal functional cartography of non-primary auditory cortex is established following early cochlear implantation. To accomplish this, we will reversibly deactivate AAF and PAF cortices in the CD cats with cochlear implants while performing the battery of auditory tasks described above, and compare the results with those from the intact cats in Aim 1. The results from these studies will be directly applicable to clinical situations concerning the functional outcomes of cochlear implants in young children.