Investigating human non-lemniscal inferior colliculus contributions to auditory learning with 7T MRI

使用 7T MRI 研究人类非丘系下丘对听觉学习的贡献

• 批准号: 10928960
• 负责人: Kevin Richard Sitek
• 金额: $ 13.41万
• 依托单位: NORTHWESTERN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-16 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10928960
• 关键词: Investigating; human; non; lemniscal; inferior

PROJECT SUMMARY Human inferior colliculus (IC) plays a critical role in auditory processing. However, the anatomy and function of the lemniscal (primary) and non-lemniscal subdivisions of IC in living humans are poorly understood due to the technical challenges of in vivo magnetic resonance imaging (MRI) of the small midbrain structures deep within the brain. In particular, despite predominant top-down and bottom-up theories of auditory learning, the neural systems underlying human speech category learning is unknown. Recent advances in MRI acquisition open the door for focused investigations into the anatomy and functional processing of human auditory midbrain. My research environment and mentor team will allow me to gain the expertise necessary to independently investigate the subcortical auditory system in living humans using MRI. In this project, we will use ultra-high field 7T MRI to quantify anatomical midbrain tissue contrast in a sub- structure dependent manner. We will also map the structural connections from each IC subdivision throughout the auditory system. Quantifying the specific anatomical MRI contrasts and connectivity patterns in living human midbrain will enable future clinical applications for investigating hearing disorders such as sensorineural hearing loss and tinnitus. A possible functional role for non-lemniscal IC is in learning novel speech sound categories. We will collect 7T functional MRI at multiple timepoints during a sound-to-category learning program to assess the contribution of IC and auditory cortex to sound category learning. Our results will elucidate whether novel categories are learned via cortically driven plasticity (cortex represents categorical features at an earlier stage than IC’s relevant acoustic enhancement) or stimulus feature enhancement (IC and cortex have similar time courses of plasticity). Existing methods for probing auditory processing, such as the scalp-recorded frequency following response (FFR), have both subcortical and cortical generators, but their relative contributions throughout the auditory learning process have not been investigated in humans. Participants in our sound-to-category learning paradigm will also undergo FFR recordings. Using representational similarity analysis, we will assess whether sound category feature representation in FFRs primarily follows that of auditory cortex or that of IC, suggesting the relative contribution of each generator at each phase of sound-to-category learning. This project implements state-of-the-art anatomical and functional 7T MRI techniques to quantify foundational characteristics of the human inferior colliculus, a key but poorly investigated subcortical auditory structure. The methods we utilized can be adapted to investigate other small, deep structures throughout the human auditory system and will enhance our understanding of IC contributions to tinnitus and optimal placement of auditory brain implants for individuals with sensorineural hearing loss.

项目摘要 人类下丘（IC）在听觉信息处理中起着重要作用。然而，解剖学和 在活体人类中，IC的丘系（初级）和非丘系亚部的功能知之甚少 由于小中脑结构的体内磁共振成像（MRI）的技术挑战 在大脑深处特别是，尽管听觉学习的理论主要是自上而下和自下而上的， 人类语音类别学习的神经系统是未知的。磁共振成像采集的最新进展 为深入研究人类听觉中脑的解剖学和功能处理打开了大门。 我的研究环境和导师团队将使我获得独立工作所需的专业知识。 用核磁共振成像研究人类皮层下听觉系统。 在这个项目中，我们将使用超高场7T MRI来量化解剖中脑组织对比度， 结构依赖方式。我们还将映射整个IC细分的结构连接 听觉系统量化活体人体特定解剖MRI对比度和连接模式 中脑将使未来的临床应用研究听力障碍，如感觉神经性听力 丧失和耳鸣。 非丘系IC的一个可能的功能作用是学习新的语音类别。我们将 在声音到类别学习计划期间的多个时间点收集7T功能MRI，以评估 IC和听觉皮层对声音类别学习的贡献。我们的研究结果将阐明是否新颖 类别是通过皮层驱动的可塑性（皮层代表早期阶段的类别特征）来学习的 比IC的相关声学增强）或刺激特征增强（IC和皮层具有相似的时间 可塑性）。 探测听觉处理的现有方法，例如以下头皮记录的频率 反应（FFR），有皮质下和皮质发生器，但它们在整个过程中的相对贡献 听觉学习过程尚未在人类中进行过研究。我们的声音到类别学习的参与者 paradigm还将进行FFR记录。使用代表性相似性分析，我们将评估是否 FFR中的声音类别特征表征主要遵循听觉皮层或IC的表征，这表明 每个发生器在声音到类别学习的每个阶段的相对贡献。 该项目采用最先进的解剖和功能7T MRI技术， 人类下丘的基本特征，一个关键的，但研究不足的皮质下听觉 结构我们使用的方法可以适用于研究整个地球上其他小而深的结构。 人的听觉系统，并将提高我们对IC的贡献耳鸣和最佳安置的理解 听觉大脑植入物，用于感音神经性听力损失患者。