Doctoral Dissertation Research: The striatum in the evolution of flexibile, learned vocal communication

博士论文研究：纹状体在灵活、学习性声音交流进化中的作用

• 批准号: 1341143
• 负责人: Chet Sherwood
• 金额: $ 1.21万
• 依托单位: George Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1341143&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; striatum; evolution

Despite numerous hypotheses concerning language evolution, the neurobiological origins of the human capacity to speak remain little understood. Studies suggest that the striatum, a subcortical structure forming complex connections with the cerebral cortex, may be important in the evolution of vocal learning - the capacity to modify vocalizations in response to social experience - which is necessary to acquire speech during development. The striatum also is a key site of expression of FOXP2, a gene that underwent positive selection in modern humans, and, in a mutated form, is responsible for a hereditary disorder affecting language production. To date, however, evidence indicating a role of the striatum in the evolution of speech and language mainly comes from experimental species, such as birds and mice, which are evolutionarily distant from humans. The aim of the current project by doctoral student Serena Bianchi (George Washington University), under the guidance of Dr. Chet Sherwood, is to identify neural features of the non-human primate striatum that may have been associated with the evolution of the capacity for vocal learning that characterizes human speech. To this end, this project uses non-invasive neuroimaging techniques, and post-mortem histological and molecular analyses, to examine the striatum of captive chimpanzees for which the use of learned, voluntarily controlled vocalizations produced to attract the attention of the experimenter (attention-getting vocalizations) has been documented. Specific aims include assessing whether the striatum of chimpanzees who produce attention-getting vocalizations differs from chimpanzees that do not exhibit this vocal phenotype in 1) morphology, and pattern of connections with motor and language-related regions of the cerebral cortex; and 2) neuronal plasticity and expression of proteins associated with synaptic functions and FOXP2. Investigating the neurobiology of vocal communication in an animal model evolutionarily close to humans may help identify precursors to speech production within a Darwinian framework of language origins as 'descent with modifications' of existing neural structures in the non-human primate brain. As part of this project, dissemination of knowledge about the evolution of the brain and language will be fostered through collaboration with the outreach program of the Smithsonian National Museum of Natural History, and the development of on-line resources and teaching materials. In addition, the histological collection created by this project will be made available to other researchers.

尽管有许多关于语言进化的假设，但人类说话能力的神经生物学起源仍然知之甚少。研究表明，纹状体是一种与大脑皮层形成复杂连接的皮质下结构，可能在声音学习的进化中发挥重要作用，即根据社会经验修改发声的能力，这是在发育过程中获得言语所必需的。纹状体也是 FOXP2 表达的关键位点，FOXP2 是一种在现代人类中经历正向选择的基因，并且以突变形式导致影响语言产生的遗传性疾病。然而，迄今为止，表明纹状体在言语和语言进化中发挥作用的证据主要来自实验物种，例如鸟类和小鼠，它们在进化上与人类相距甚远。博士生 Serena Bianchi（乔治华盛顿大学）当前项目的目的是在 Chet Sherwood 博士的指导下，确定非人类灵长类纹状体的神经特征，这些特征可能与能力的进化有关。声音学习是人类言语的特征。为此，该项目使用非侵入性神经影像技术以及死后组织学和分子分析来检查圈养黑猩猩的纹状体，其中使用习得的、自愿控制的发声来吸引实验者的注意（注意-获得发声）已被记录。具体目标包括评估发出引人注目的发声的黑猩猩的纹状体是否与不表现出这种发声表型的黑猩猩的不同之处在于：1）形态，以及与大脑皮层运动和语言相关区域的连接模式； 2) 神经元可塑性以及与突触功能和 FOXP2 相关的蛋白质的表达。在进化上与人类接近的动物模型中研究声音交流的神经生物学可能有助于在达尔文语言起源框架内识别言语产生的前兆，即非人类灵长类大脑中现有神经结构的“修改后的后代”。作为该项目的一部分，将通过与史密森国家自然历史博物馆的外展计划合作以及开发在线资源和教材来促进有关大脑和语言进化的知识传播。此外，该项目创建的组织学收藏将提供给其他研究人员。