HUMAN MIDDLE LATENCY AUDITORY EVOKED POTENTIALS

中潜伏期听觉诱发电位(MAEP，潜伏期10-70毫秒) 提供与以下各项相关的电活动的直接测量 人类声音的短潜伏期丘脑和大脑皮层分析。然而， 尽管临床应用越来越多，但人们对它们的大部分了解很少 基本属性。例如，大脑皮层和皮质下 涉及MAEP生成的结构仍然存在争议，而且它是 不确定它们是如何组织的：它们是否有主位和/或空间位 在许多物种中，组织喜欢听觉结构？ 我们将在五个实验中解决这些基本问题。两种新技术 将被纳入所有研究中。首先，我们会记录详细的头皮 32个电极的形貌和提取拉普拉斯MAEP(LAP-MAEP) 在时间上的地点。LAP-MAEP提高MAEP对焦点的分辨率 听觉皮质中的发电机。第二，我们将关联MAEP分布 通过测量候选MAEP生成器的相对方向 直接从高分辨率核磁共振扫描。我们将使用这些改进后的 研究MAEP生成器的组织以处理 强度(实验I)、频率(实验II)和空间位置 (实验III)听觉信号。 关于MAEP生成器的假设将在两个实验中得到进一步验证 充分利用我们分布广泛的临床人群。在……里面 实验四，我们将在有局灶性病变的患者组中记录MAEP 候选MAEP生成器，包括上位时间平面和 听觉皮质、额叶背外侧、顶下叶、 丘脑后部和基底节。在实验五中，我们将比较 手术患者头皮和皮质表面的MAEP 开颅手术。在正常受试者和患者身上的实验形成了一个 全面的序列，将提供更好的理解 对人脑中声音的短时分析，并增强 MAEP在神经外科和神经外科中的临床应用。

Middle latency auditory evoked potential (MAEPs, latencies 10-70 msec) provide a direct measure of the electrical activity associated with the short-latency thalamic and cortical analysis of sounds in humans. However, despite increasing clinical use little is known about their most fundamental properties. For example, the cortical and subcortical structures involved in MAEP generation remain in dispute, and it is uncertain how they are organized: do they have tonotopic and/or spatiotopic organizations like auditory structures in many species? We will address these basic issues in five experiments. Two new techniques will be incorporated in all studies. First, we will record detailed scalp topographies from 32 electrodes and extract Laplacean MAEPs (LAP-MAEPs) over temporal sites. LAP-MAEPs enhance the resolution of MAEPs to focal generators in auditory cortex. Second, we will correlate MAEP distributions with the relative orientations of candidate MAEP generators measured directly from high-resolution MRI scans. We will use these improved techniques to study the organization of MAEP generators for processing the intensity (Experiment I), frequency (Experiment II), and spatial position (Experiment III) of auditory signals. Hypotheses about MAEP generators will be further tested in two experiments that take advantage of our well-delineated clinical populations. In Experiment IV, we will record MAEPs in patient groups with focal lesions of candidate MAEP generators, including the superior temporal plane and auditory cortex, dorsolateral frontal cortex, inferior parietal lobe, the posterior thalamus and basal ganglia. In Experiment V, we will compare MAEPs from the scalp and cortical surface in patient undergoing craniotomies. The experiments in normal subjects and patients form a comprehensive sequence that will provide a better understanding of the shortlatency analysis of sounds in the human brain, and enhance the clinical utility of MAEPs in neurological and neurosurgical applications.