CORTICAL REPRESENTATION OF AUDITORY SPACE

临床和动物研究表明，听觉损伤 皮层的损伤会导致声音定位能力的缺陷。 从生理学角度解释这些观察结果的努力 无法识别声音位置的皮层表征， 和当前的观点， 大脑皮层的听觉通路与简单的听觉通路不一致 听觉空间的映射 中脑的结构，上级 丘，确实包含这样的地图，其中的位置，一个声音， 源由单个焦点的位置表示， 最大限度地激活神经元，令人困惑的是，类似的地图 在大脑皮层中还没有被描述过。 一种可能是 上级丘的听觉地图是 感觉运动整合发生在丘， 因此是该结构所独有的。 在大脑皮层， 声音可以由以下特征模式来表示： 包括多个活性区域而不是单个病灶的激活 的活动。 另一种可能是听觉空间 但之前的研究都集中在 在大脑皮层的错误区域或者使用了不恰当的 刺激。 拟议的实验将使用宽带刺激 在自由声场中呈现，以表征 与特定位置相关的皮层活动。 特别 将注意力放在大量未开发的非音调拓扑 区域，包括第二听觉区域（A2），其呈现为 先验地是最有可能包含空间 表示. 这些实验的结果将表明 听觉空间在大脑皮层中是否由一对一的 一张空间地图，或者其他一些更分散的模式， 活动 听觉皮质是颞叶的关键组成部分，它 它本身就是许多交流过程的皮层基底。 对听觉皮层功能组织的理解 可能导致诊断程序的发展， 颞叶病理学评估。 听觉空间 在这个意义上，代表性特别重要，因为来源 位置是声音的少数几个基本特征之一， 显然没有双边代表。 在更广泛的范围内， 建议的研究将有助于基本了解 皮质功能是必不可少的发展 对脑损伤和疾病的适当治疗反应。

Clinical and animal studies indicate that lesions of the auditory cortex can result in deficits in the ability to localize a sound. Efforts to account for these observations in physiological terms have failed to identify a cortical representation of sound location, and the current view of the tonotopically organized primary auditory pathway to the cortex is inconsistent with a simple one- to-one map of auditory space. A midbrain structure, the superior colliculus, does contain such map in which the location of a sound source is represented by the position of a single focus of maximally activated neurons, and it is puzzling that a similar map has not been described in the cortex. One possibility is that the auditory map in the superior colliculus is a product of the sensorimotor integration which takes place in the colliculus and, thus, is unique to that structure. In the cortex, the location of a sound might be represented by characteristic patterns of activation comprising multiple active areas rather than single foci of activity. An alternative possibility is that auditory space is mapped in the cortex, but previous efforts to find it have focused on the wrong areas of the cortex or have used inappropriate stimuli. The proposed experiments will use broad band stimuli presented in a free sound field to characterize the patterns of cortical activity associated with specific locations. Particular attention will be given to the largely-unexplored non-tonotopic areas, including the second auditory area (A2), which appear a priori to be the most likely areas to contain a spatial representation. Results of these experiments will indicate whether auditory space is represented in the cortex by a one-to- one map of space or by some other, more distributed, pattern of activity. The auditory cortex is a key element of the temporal lobe, which is itself the cortical substrate for many communicative processes. An understanding of functional organization in the auditory cortex could lead to the development of diagnostic procedures for evaluation of temporal lobe pathology. Auditory spatial representation is particularly relevant in that sense, since source location is one of the few basic features of a sound which apparently is not represented bilaterally. On a broader scale, the proposed research will contribute to the basic understanding of cortical function which is essential for the development of appropriate therapeutic responses to brain injury and disease.