Anatomical/functional parcellation of human auditory cortex with 7T MRI

描述（由申请人提供）：尽管在过去几十年中科学进步迅速，但人类听觉系统的功能结构仍然难以捉摸。识别人类听觉皮层（AC）子区域的困难导致了对声音处理的基本理论分歧。与此同时，许多人经历注意力和听觉处理困难，严重妨碍了他们的日常功能。因此，阐明人类听觉系统的功能结构具有科学和公共卫生意义。 在以前的动物模型中，AC场的边界，对不同的声音特征敏感的子区域，已经基于音调定位（或耳蜗定位）梯度的反转来识别。不幸的是，在人类中，相应的AC场边界一直难以在体内勾勒。在比较的视觉皮层子字段，其中许多几乎可以常规确定使用功能性磁共振成像（fMRI）定位任务，推定的AC子区域是非常小的。因此，当使用常规成像分辨率（3-6 mm各向同性体素）时，AC场边界容易模糊。这项研究计划利用超高场（7 T）功能磁共振成像技术的最新进展，以更高的分辨率和精度比以前实现的人类AC领域。先前的功能磁共振成像研究已经复杂的因素，偏差测量的血氧水平依赖（BOLD）信号远离原来的网站的神经元活动。这种混淆的一个重要来源是皮质表面附近的大引流血管。我们应用了一种新的基于层流表面的fMRI分析方法，以避免软脑膜血管的偏差，结合基于表面的解剖配准方法，将改善受试者间的分析（目标1）。此外，我们将使用髓鞘加权解剖MRI（目的2）描绘AC核心区域的边界。目标1和目标2的结果将结合起来，以创建人类AC的概率模型。 在这个提议中，我们将采用一种新的基于层状表面的功能磁共振成像分析方法，以比以前更高的分辨率和准确性来研究人类听觉皮层的功能解剖。这将有助于实现对人类大脑中声音处理的更高级的系统级理解。虽然参与者将是健康的受试者，但结果可能有助于推进与听觉感知缺陷相关的各种疾病的研究。

DESCRIPTION (provided by applicant): Despite the rapid scientific progress during the past decades, the functional architecture of human auditory system still remains elusive. The difficulty of identifying human auditory cortex (AC) subregions has contributed to fundamental theoretical disagreements on sound processing. At the same time, numerous individuals experience attention and auditory processing difficulties that significantly hamper their everyday function. Elucidating human auditory system functional architecture has, thus, both scientific and public health significance. In previous animal models, boundaries of AC fields, subregions sensitive to distinct sound features, have been identified based on reversals of tonotopic (or cochleotopic) gradients. Unfortunately, in humans, the corresponding AC-field boundaries have been difficult to outline in vivo. In comparison to visual cortex subfields, many of which can be almost routinely identified using functional MRI (fMRI) localizer tasks, the putative AC subregions are very small. The AC field boundaries are, thus, easily blurred when conventional imaging resolutions (3-6 mm isotropic voxels) are being utilized. This research program utilizes recent advances in ultra-high field (7T) fMRI techniques to localize human AC fields at higher resolution and accuracy than previously achieved. Previous fMRI studies have been complicated by factors that bias the measured blood-oxygen level dependent (BOLD) signal away from the original site of the neuronal activity. A significant source for such confounds are the large draining vessels near the cortical surface. We apply a novel laminar surface-based fMRI analysis method to avoid biases from pial vessels, combined with surface-based anatomical registration methods that will improve inter-subject analyses (Aim 1). Further, we will delineate the boundaries of AC core region using myelin-weighted anatomical MRI (Aim 2). The results of Aims 1 and 2 will be combined to create a probabilistic model of human AC. In this proposal, we will apply a novel laminar surface-based fMRI analysis method to investigate the functional anatomy of human auditory cortex at considerably higher resolution and accuracy than previously possible. This will help achieve a more advanced system-level understanding of sound processing in the human brain. Although the participants will be healthy subjects, the results will likely help advance studies on a variety of disorders associated with deficits in auditory perception.