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: 10371381
• 负责人: Kevin Richard Sitek
• 金额: $ 14.05万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 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/10371381
• 关键词: Acoustics; Adult; Anatomy; Animal Model; Auditory; Auditory area; Auditory system; Brain; Brain region; Categories; Cell Nucleus; Clinical; Cochlear Implants; Communication; Complex; Diffusion Magnetic Resonance Imaging; Dorsal; Ear; Electrophysiology (science); Environment; Foundations; Frequencies; Functional Magnetic Resonance Imaging; Future; Hearing problem; Human; Human Characteristics; Image; Imaging Techniques; Implant; Individual; Inferior Colliculus; Investigation; Learning; Location; Magnetic Resonance Imaging; Maps; Mediating; Mentors; Methodology; Methods; Midbrain structure; Participant; Pathway interactions; Pattern; Phase; Play; Process; Property; Protocols documentation; Research; Research Project Grants; Resolution; Role; Route; Scalp structure; Self-Help Devices; Sensorineural Hearing Loss; Sensory Disorders; Signal Transduction; Specificity; Speech; Speech Sound; Stimulus; Structure; System; Testing; Time; Tinnitus; Tissues; Training; auditory pathway; auditory processing; auditory thalamus; base; clinical application; clinically relevant; contrast imaging; hearing impairment; in vivo; in vivo imaging; magnetic field; neural implant; next generation; novel; programs; relating to nervous system; response; sound; theories; tractography; white matter

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.

项目概要 人类下丘（IC）在听觉处理中起着至关重要的作用。然而，解剖学和 IC 的丘系（初级）和非丘系细分在活人中的功能知之甚少 由于小型中脑结构的体内磁共振成像（MRI）的技术挑战 大脑深处。特别是，尽管听觉学习的自上而下和自下而上的理论占主导地位， 人类语音类别学习背后的神经系统尚不清楚。 MRI 采集的最新进展 为集中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所需的专业知识 使用 MRI 研究活人的皮层下听觉系统。 在这个项目中，我们将使用超高场 7T MRI 来量化亚组中的解剖中脑组织对比度 结构依赖方式。我们还将绘制整个 IC 细分领域的结构连接图 听觉系统。量化活人的特定解剖 MRI 对比和连接模式 中脑将使未来的临床应用能够用于研究听力障碍，例如感音神经性听力 损失和耳鸣。 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收集多个时间点的 7T 功能 MRI，以评估 IC 和听觉皮层对声音类别学习的贡献。我们的结果将阐明是否新颖 类别是通过皮质驱动的可塑性学习的（皮质代表早期阶段的分类特征 比 IC 相关的声学增强）或刺激特征增强（IC 和皮层具有相似的时间 可塑性课程）。 现有的探测听觉处理的方法，例如头皮记录的频率跟踪 响应（FFR），同时具有皮质下和皮质发生器，但它们在整个过程中的相对贡献 尚未对人类的听觉学习过程进行过研究。声音到类别学习的参与者 范式也将进行 FFR 录音。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示主要遵循听觉皮层或 IC 的特征表示，表明 每个生成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 技术来量化 人类下丘的基本特征，一个关键但研究不足的皮层下听觉 结构。我们使用的方法可以适用于研究整个宇宙中的其他小型深层结构 人类听觉系统，将增强我们对 IC 对耳鸣的贡献和最佳放置的理解 为感音神经性听力损失患者进行听觉脑植入。