Functional Organization of Primary Auditory Cortex

描述（由申请人提供）：本实验的长期目标是确定复杂声音的皮层感受野转换和表征的基本处理原则和策略。我们将对比成年猫的两个主要听觉场，Al和AAF的组织，并具体参考功能域和层流组织。一个主要的前提是，人工智能和AAF在很大程度上接受独立的丘脑和皮层输入，并且具有可能构成任务特定处理流的特定功能差异。输入在来源位置和功能属性上有何不同？丘脑输入对感受野（RF）多样性的产生有何贡献？皮层输入层的功能特征是如何在输出层中转换的？在电生理和神经解剖学的联合实验中，将研究功能特性的异质空间分布与这些主要领域的连接模式之间的相互关系。通过将功能特性和皮层连通性联系起来，可以评估简单和复杂声音的皮层表征和转换特征的总体原则。第一个目标是为简单和复杂的声音定义ai和AAF的层特定功能组织。我们认为，Illb/IV层的单个神经元与其他层的细胞在RF属性上存在系统性差异。rf将通过传统刺激以及反向相关方法获得，该方法可以创建双耳光谱-时间接受野。我们还将比较麻醉猫的Al和AAF以及清醒松鼠猴的AI中RF特性的层特异性变化，以解决清醒动物的比较问题和RF组织。第二个目的是通过同时记录猫内侧膝状体和AI/AAF的功能连接神经元对，直接比较丘脑源和皮层靶点的rf。假设丘脑输入特性近似于其皮层目标的某些射频特性，但许多皮质射频的构建实质上是由皮质的贡献决定的。最后，我们将把丘脑和皮质内连接与Al和AAF的功能亚区联系起来。斑驳的丘脑和皮质投射与斑驳的皮层组织在光谱、时间和双耳特性上的关系是主要的问题。将逆行示踪剂注射到cat AI/AAF生理定义的功能区，并相对于功能图进行评估。这些研究将建立初级皮质场信号处理的功能和结构框架。了解这些原理对于理解听觉皮层中的信息流、正常听觉处理和感知学习的回路以及它们对听觉障碍的贡献至关重要。

DESCRIPTION (provided by applicant): The long-term goal of the proposed experiments is to identify the fundamental processing principles and strategies that underlie the cortical receptive field transformations and representations of complex sounds. We will contrast the organization of two primary auditory fields, Al and AAF, in adult cat with specific reference to functional domains and laminar organization. A main premise is that Al and AAF receive largely independent thalamic and cortical inputs and have specific functional differences that may constitute task specific processing streams. How do the inputs differ in source location and functional properties; what do the thalamic inputs contribute to the generation of receptive field (RF) diversity; and how are the functional characteristics at the cortical input level transformed in the output layers? The interrelations between heterogeneous spatial distributions of functional properties and the connection patterns of these primary fields will be studied in joint electrophysiological and neuroanatomical experiments. By relating the functional properties and cortical connectivity, global principles underlying the characteristics of cortical representations and transformations can be assessed for simple and complex sounds. . The first aim is to define layer-specific functional organizations of Al and AAF for simple and complex sounds. We think that single neurons in layers Illb/IV will show systematic differences in RF attributes from cells in other layers. RFs will be obtained with traditional stimuli as well as with a reverse-correlation method that creates binaural spectro-temporal receptive fields. We will also compare the lamina-specific changes in RF properties in Al and AAF of the anesthetized cat and in AI of the awake squirrel monkey to address comparative questions and RF organization in conscious animals. The second aim is to compare directly the RFs of thalamic sources and cortical targets by simultaneous recording of functionally connected neuron pairs in cat medial geniculate body and AI/AAF. It is hypothesized that thalamic input properties approximate some RF properties of their cortical targets but that construction of many cortical RFs is substantially shaped by corticocortical contributions. Finally, we will relate thalamic and intracortical connections to functional sub-regions of Al and AAF. How patchy thalamic and corticocortical projections are related to the patchy cortical organizations found for spectral, temporal and binaural properties is the main question. Labeling from retrograde tracers injected into physiologically defined functional zones in cat AI/AAF will be assessed relative to functional maps. These studies will establish a functional and structural framework of signal processing in primary cortical fields. Insight into these principles is crucial for understanding the flow of information in auditory cortex, the circuits for normal auditory processing and perceptual learning, and their contributions to auditory disorders.