Visual and Auditory Processing Streams in the Cerebral Cortex

描述(申请人提供)：长期以来，视觉一直是健康和疾病中的一个模型系统，用于在大脑皮层水平上分析感知和认知系统。近年来，在对听觉认知所涉及的高级皮质区域的理解方面也取得了很大进展。然而，关于听觉处理流的知识仍然远远落后于视觉。我们建议使用单单位和多单位电生理学来研究非人类灵长类动物恒河猴的沿颞上回(STG)和沟(STS)的皮质区域，猕猴的皮质组织与人类相似。我们的分析是基于这样的假设，即视觉和听觉系统中都存在至少两个专门的加工流，一个是用于识别物体的前腹加工流，一个是用于空间分析的后背加工流。因此，我们预测，初级听觉皮质(A1)吻侧和外侧的前上颞区(AST)对听觉对象的选择性与空间位置无关(特定目标1)，而A1尾部的后上颞区(PST)无论听觉对象类型(特定目标2)如何，对空间位置的选择性都增强(特定目标2)。我们将专注于物种特定交流呼叫的处理，并将测试上颞叶(ST)皮质中的神经元是否能够形成音调和呼叫者身份的不变性。在第三个特定目标中，我们将使用解剖学示踪剂，注射到生理特征区域，以揭示从听觉、视觉和多感官区域到AST和PST的输入连接。我们的研究使用在行为任务中训练的警觉猴子，将有助于理解跨感觉系统的感知和认知的统一原则。它们将进一步加深我们对中风或阿尔茨海默病导致的人类认知缺陷的理解，这些缺陷会导致视觉和听觉失认以及空间定向丧失。这些研究也与阅读障碍和自闭症等障碍有关，这些障碍包括阅读理解或社交能力方面的问题。听觉处理缺陷是两者的共同症状，澄清听觉皮质交流的神经机制是找到治疗方法的主要先决条件。最后，了解颞叶皮质与额叶皮质的大量联系将为更高级别的精神障碍提供重要线索，例如精神分裂症，这种疾病通常以幻听为特征。

DESCRIPTION (provided by applicant): Vision has long served as a model system in health and disease for the analysis of perceptual and cognitive systems at the level of the cerebral cortex. Great progress has also been made in recent years regarding an understanding of higher cortical areas involved in auditory cognition. However, knowledge about auditory processing streams still lags far behind that in vision. We propose to use single-and multi-unit electrophysiology to study cortical areas along the superior temporal gyrus (STG) and sulcus (STS) in a nonhuman primate, the rhesus macaque, whose cortical organization is similar to that of humans. Our analysis is based on the hypothesis that at least 2 specialized processing streams exist both in the visual and auditory system, an antero-ventral stream for the identification of objects, and a postero-dorsal stream for the analysis of space. Thus we predict that anterior superior temporal areas (AST) rostral and lateral to primary auditory cortex (A1) show enhanced selectivity for auditory objects regardless of spatial location (Specific Aim 1), whereas posterior superior temporal areas (PST) caudal to A1 show enhanced selectivity for location in space regardless of auditory object type (Specific Aim 2). We will focus on the processing of species-specific communication calls and will test whether neurons in the superior temporal (ST) cortex can form invariances for pitch and caller identity. In a third Specific Aim, we will use anatomical tracers, injected into physiologically characterized regions, to uncover the input connections to AST and PST from auditory, visual, and multisensory areas. Our studies, using alert monkeys trained in a behavioral task, will contribute to the understanding of unified principles of perception and cognition across sensory systems. They will further our understanding of deficits in human cognition from stroke or Alzheimer's disease, which result in visual and auditory agnosia as well as loss of spatial orientation. The studies are also relevant for disorders such as dyslexia and autism, which include problems in reading comprehension or a person's ability for social communication. Auditory processing deficits are a common symptom in both, and clarification of the neural mechanisms for auditory cortical communication is a major prerequisite for finding a cure. Finally, understanding temporal cortex with its massive connections to frontal cortex will yield important clues about higher mental disorders, such as schizophrenia, which are often characterized by auditory hallucinations.