The Size of a Cortical Representation

皮质表征的大小

• 批准号: 7740141
• 负责人: RON D FROSTIG
• 金额: $ 33.13万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-12-15 至 2012-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7740141
• 关键词: Accounting; Action Potentials; Address; Adult; Animal Model; Animals; Area; Auditory; Auditory area; Brain; Data; Electrodes; Epithelium; Event; Face; Figs - dietary; Flowers; Functional Imaging; Histology; Human; Image; Lead; Location; Maps; Measures; Metaphor; Modality; Neurons; Principal Investigator; Rattus; Reliance; Research; Resolution; Sensory; Signal Transduction; Somatosensory Cortex; Staining method; Stains; Stimulus; Structure-Activity Relationship; Synaptic Potentials; Testing; Vibrissae; Visual; Water; area striata; barrel cortex; base; cytochrome c oxidase; experience; hemodynamics; imaging modality; interest; optical imaging; programs; research study; response; sensory cortex; somatosensory; tool

DESCRIPTION (provided by applicant): Our research interests focus on the topographical mapping of sensory epithelia in sensory cortex and their plasticity. We are particularly interested in delineating the spatial extent of cortical activation (e.g., the spatial spread of all the responding neurons) to small (point) stimulation because it is fundamental to our understanding of cortical maps. Functional imaging methods are advantageous for characterizing the spatial extent because of their ability to provide quick, high spatial resolution assessment of activity from large cortical regions. However, one limitation of most of the functional imaging methods is that they rely on hemodynamic events that follow brain activation and therefore provide only an indirect means for assessing the spatial extent of the underlying neuronal evoked activation and thus imagers lack the means to assess the spread of neuronal activation using imaging. Because there is no direct way to verify the spatial extent of the underlying neuronal activation area in humans, imagers typically apply conservative thresholds for analysis that typically emphasize peak, or near peak activation areas. Such practice, however, may lead to a biased and possibly distorted view of cortical function because it may underestimate the real size of cortical activation. To address these issues, it is proposed to directly relate the spread of neuronal activation to the spread imaged by functional imaging of the same cortical area with the same stimulation. The point stimulation is either a whisker or a pure tone, and the spread of cortical activation is imaged by intrinsic signal optical imaging in the adult rat somatosensory and auditory cortex, respectively. Imaging results will be directly compared to post-imaging neuronal recording using electrode arrays within the imaged cortex. Imaging and neuronal results, in turn, will also be superimposed on the anatomical maps of the same areas to highlight cortical structure-function relationship related to the spread of activity. Because functional imaging methods can detect both suprathreshold (action potentials) and subthreshold (local field potentials), the spread of both types of neuronal activations will be recorded and compared with imaging results. Once the rules of mapping neuronal spread to imaging spread are quantified, it will enable unbiased, direct, imaging-based description of the entire somatosensory and auditory cortices using such rules.

描述（由申请人提供）：我们的研究兴趣集中在感觉皮层中感觉上皮的地形图及其可塑性。我们对描述皮质激活的空间范围（例如，所有响应神经元的空间扩散）对小（点）刺激的空间范围特别感兴趣，因为这对于我们对皮质图的理解至关重要。功能成像方法对于表征空间范围而具有优势，因为它们能够对大型皮质区域的活动进行快速，高空间分辨率评估。但是，大多数功能成像方法的一个局限性是它们依赖于遵循大脑激活的血液动力学事件，因此仅提供了一种间接手段来评估潜在神经元诱发的激活的空间范围，因此成像器缺乏使用成像评估神经元激活传播的手段。由于没有直接的方法可以验证人类基础神经元激活区域的空间范围，因此成像器通常将保守的阈值应用于通常强调峰值或接近峰值激活区域的分析。但是，这种做法可能导致皮质功能的偏见且可能扭曲的视图，因为它可能低估了皮质激活的实际规模。为了解决这些问题，建议将神经元激活的传播与具有相同刺激的同一皮质区域的功能成像成像所成像的扩散。点刺激是晶须或纯音，皮质激活的扩散是由成年大鼠体感和听觉皮层的固有信号光学成像成像的。成像结果将直接与使用成像皮层内的电极阵列进行后成像神经元记录进行比较。成像和神经元结果反过来也将叠加在同一区域的解剖图上，以突出与活动扩散有关的皮质结构 - 功能关系。由于功能成像方法可以检测到上牙（行动电位）和亚阈值（局部田间电位），因此将记录两种类型的神经元激活的传播，并将其与成像结果进行比较。一旦量化神经元扩散到成像传播的规则，它将使用此类规则实现对整个体感和听觉皮层的无偏，直接，基于成像的描述。