Role of Sensory Experience in Parcellation of Sensory Neocortex

感觉体验在感觉新皮质分区中的作用

• 批准号: 0451018
• 负责人: Sarah Pallas
• 金额: --
• 依托单位: Georgia State University Research Foundation, Inc.
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0451018&HistoricalAwards=false
• 关键词: Role; Sensory; Experience; Parcellation; Neocortex

Project SummaryCerebral cortex in mammals is composed of multiple specialized subdivisions called "areas", but how they arise during either development or evolution is not known. An understanding of this process is important for our ability to understand how human cortex functions. The major hypothesis guiding this work is that sensory information received by a cortical area plays a significant role in defining its identity and organizing its circuitry. The function of a cortical area would thus be automatically designed for optimal processing of its inputs, even if inputs change over evolutionary time or as a response to injury. In contrast to a preprogrammed blueprint, this input-dependent organization would allow an optimal response to changes in sensory inputs. The continuing goal is to examine how developmental mechanisms could facilitate evolution of sensory cortex into its functionally specialized areas. Two paradigms will be used to investigate the role of sensory experience in cortical development in ferrets, using electrophysiological and neuroanatomical approaches. In one model, neonatal deafening produces errors in targeting such that visual thalamus innervates primary auditory cortex (AI). An investigation into the functional result of the deafness-induced rewiring is proposed here. In the other paradigm, immature retinal axons are encouraged to invade the auditory thalamus, providing visual input to A1 via the auditory pathway. Physiological study showed that as a result of the procedure, auditory cortex comes to resemble visual cortex in its mapping, response properties, and perceptual capability. Thus it appears that supplying AI with early visual input can nearly transform it into visual cortex from a functional standpoint. This apparently occurs through alterations in connectivity and in structure of a class of inhibitory cortical neurons. The objectives for this model are to continue to define the functional implications of the changes in connectivity and neuronal morphology believed to underlie cortical plasticity. This information will demonstrate what types of changes in circuitry would be sufficient for a sensory cortical area to acquire unique properties during evolution. The possibility that changing afferent activity and/or genetic identity can induce a new cortical area will be explored. The findings will be applied to models of developmental processes that act as a basis for brain evolution, and in particular models of how the number and specialization of sensory cortical areas increased during mammalian evolution.Broader Impact: Over 30% of Georgia State University students are African-American, facilitating recruitment of minority students into biological research. In addition to ongoing activities in undergraduate and graduate education, community outreach activities have and will include development of elementary and middle school lesson plans in brain development and evolution. These lessons will be adapted for use by teachers and in the NSF-funded "Bio-Bus" that travels to metro Atlanta area schools, providing hands-on biology lessons particularly for under-funded public schools with a majority African-American student population. In the context of the NSF Center for Behavioral Neuroscience, the P.I. will continue to recruit minority undergraduate students for summer research experiences with the goal of encouraging them toward graduate school. The PI has also worked to defend evolution education in Georgia through articles for the lay press, radio and TV, and through educational outreach and networking between K-12 and university faculty. See http://www.georgiascience/org.

哺乳动物的大脑皮层由多个专门的细分组成，称为“区域”，但它们如何在发育或进化过程中出现尚不清楚。 了解这一过程对于我们理解人类大脑皮层的功能非常重要。 指导这项工作的主要假设是，皮层区域接收的感觉信息在定义其身份和组织其电路中起着重要作用。 因此，皮层区域的功能会自动设计为最佳处理其输入，即使输入随着进化时间的推移或作为对损伤的反应而改变。 与预先编程的蓝图相反，这种依赖输入的组织将允许对感官输入的变化做出最佳反应。 持续的目标是研究发育机制如何促进感觉皮层进化到其功能专门化的领域。 两个范例将被用来调查的作用，在雪貂皮层发育的感觉经验，使用电生理学和神经解剖学的方法。 在一个模型中，新生儿耳聋产生错误的目标，使视觉丘脑支配初级听觉皮层（AI）。 在这里提出了一个调查的功能性结果的双折射引起的重新布线。 在另一个范例中，未成熟的视网膜轴突被鼓励侵入听觉丘脑，通过听觉通路向A1提供视觉输入。 生理学研究表明，作为该过程的结果，听觉皮层在其映射，反应特性和感知能力方面与视觉皮层相似。 因此，从功能的角度来看，为人工智能提供早期视觉输入几乎可以将其转化为视觉皮层。 这显然是通过一类抑制性皮层神经元的连接和结构的改变而发生的。 该模型的目标是继续定义被认为是皮层可塑性基础的连接和神经元形态学变化的功能意义。 这些信息将证明哪些类型的电路变化足以使感觉皮质区域在进化过程中获得独特的特性。 改变传入活动和/或遗传特性可以诱导一个新的皮质区的可能性将被探讨。 研究结果将被应用到模型的发展过程中，作为大脑进化的基础，特别是模型的数量和专业化的感觉皮层区域增加哺乳动物evolution.Broader影响：超过30%的格鲁吉亚州立大学的学生是非洲裔美国人，促进招聘少数民族学生进入生物研究。 除了正在进行的本科生和研究生教育活动外，社区外联活动已经并将包括制定小学和中学大脑发育和进化课程计划。 这些课程将被改编，供教师和国家科学基金会资助的“生物巴士”使用，该巴士前往亚特兰大大都会地区的学校，特别是为资金不足的公立学校提供动手生物课程，其中大多数是非裔美国学生。 在NSF行为神经科学中心的背景下，P.I.将继续招收少数民族本科生进行暑期研究，以鼓励他们进入研究生院。 PI还通过为非专业媒体、广播和电视撰写文章，并通过K-12和大学教师之间的教育推广和网络，努力捍卫格鲁吉亚的进化论教育。 参见http://www.georgiascience/org。