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EVOLUTION OF HEMISPHERIC ASYMMETRIES IN PERCEPTION

感知中半球不对称的演变

基本信息

批准号：
6538931
负责人：
MICHAEL S GAZZANIGA
金额：
$ 19.53万
依托单位：
DARTMOUTH COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-06-01 至 2004-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6538931
关键词：
brain interhemispheric activity cerebral dominance clinical research evolution form /pattern perception human subject language development neural information processing sensory discrimination sequential perception space perception split brain tachistoscope temporal lobe /cortex time perception visual fields visual perception visual stimulus

项目摘要

It is commonly noted that the left hemisphere is specialized for language and related cognitive processes while the right hemisphere is specialized for visuospatial processes. In this proposal, we investigate the idea that specialization of function has an associated cost. As each hemisphere becomes increasingly specialized for particular functions, we hypothesize that cortical regions are co-opted for these burgeoning functions. Since these co-opted cortical regions were previously performing some other function, that function will necessarily be adversely affected by the loss of cortex devoted to it. We hypothesize that this cost will be in higher-level perceptual functions, because lower-level perceptual functions are required by both hemispheres, and should be bilaterally represented. We hypothesize that the costs associated with hemispheric specialization are predictable. It has been hypothesized that the development of language in the left hemisphere is predicated on its relative superiority for temporal and sequential processing. We argue that this asymmetry "snowballed" over the course of human evolution, resulting in increasing specialization for timing and sequencing in the left hemisphere. This, in turn, resulted in a loss of visuospatial grain in the left hemisphere as tissue previously devoted to this function was co-opted for language. Relieved of the necessity of making such discriminations, we hypothesize that cortical resources previously dedicated to temporal processing in the right hemisphere were co-opted for fine-grained perceptual processing, effectively trading off temporal for spatial resolution. We propose to investigate the pattern of hemispheric specializations for perceptual abilities and their associated processing costs. Callosotomy ("split-brain") patients provide a unique opportunity to investigate the perceptual processes of each hemisphere in isolation. Although the notion of hemispheric specialization is not a new one, the idea that specialization has associated costs has implications for theories of brain function and for evolutionary theories of brain development.

人们通常注意到，左脑专门负责语言和相关的认知过程，而右脑专门负责视觉空间过程。在这项提案中，我们调查了职能专业化有相关成本的想法。随着每个半球变得越来越专用于特定的功能，我们假设大脑皮层区域被用于这些新兴的功能。由于这些增选的皮质区域以前执行一些其他功能，该功能必然会因专用于该功能的皮质的丧失而受到不利影响。我们假设这一代价将出现在较高级别的知觉功能中，因为较低级别的知觉功能是两个半球所需要的，应该以双边方式表示。我们假设，与半球专业化相关的成本是可以预测的。有人假设，左脑语言的发展是基于其在时间和顺序加工方面的相对优势。我们认为，这种不对称性在人类进化过程中“滚雪球”，导致左脑对时间和序列的专业化程度越来越高。这反过来又导致了左脑视觉空间颗粒的丧失，因为之前专门用于这一功能的组织被用于语言。排除了做出这种区分的必要性，我们假设，之前专门用于右脑时间处理的皮质资源被用于细粒度的感知处理，有效地权衡了时间和空间分辨率。我们建议研究知觉能力的半球特化模式及其相关的加工成本。骨痂切开术(“裂脑”)患者提供了一个独特的机会，孤立地研究每个半球的知觉过程。尽管大脑半球专业化的概念并不是一个新概念，但专业化与成本相关的想法对大脑功能理论和大脑发育进化理论都有影响。