Juxtacellular Characterization of V1 Neurons

V1 神经元的细胞旁特征

基本信息

批准号：
8122217
负责人：
MICHAEL J HAWKEN
金额：
$ 35.48万
依托单位：
NEW YORK UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-08-01 至 2013-07-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Understanding how the circuits of the cortex are organized and how they function is a central goal of neuroscience. We have been studying the primary visual cortex, V1, in order to understand its role in vision and also because V1 is one of the best understood regions of the cerebral cortex. On one hand we often have detailed knowledge of the receptive field properties of neurons determined from neuronal firing in V1, to an array of visual stimuli, obtained from extracellular recording. On the other hand from anatomical studies we know about the intricate neuronal architecture and patterns of synaptic connections both within V1 and between V1 and extrastriate cortex. Our proposal aims to bridge the gap between the structure of neurons in circuits in monkey primary visual cortex and their receptive field properties. We use a method called loose-patch juxtacellular recording to monitor extracellular action potentials, that enables us to functionally characterize the RF of the neurons, and then we label same neuron with a tracer molecule and subsequently recover and reconstruct the three dimensional dendritic and axonal arbors of the labeled neurons. Layer 4a, the main target of the magnocellular afferents from the lateral geniculate nucleus, provides input to layer 4b. Both layers have a variety of neurons with distinct morphologies. There is also a range of receptive field properties in the two layers. Our first aim is to characterize the excitatory neurons in layers 4ca and 4b. We will test the hypothesis that there are distinct functional characteristics that associate with distinct morphological types. Among the pyramidal neurons of layer 6 there are distinct classes of neurons based on their pattern of intra-cortical axonal arborization. The axonal patterns are linked to the (vi- and P-cell divisions of layer 4. We will use functional tests that allow us to determine whether labeled neurons are dominated by magnocellular or parvocellular input in addition to tuning for orientation, spatial frequency, temporal frequency and size. Our second aim is to test to what degree morphological classes have specific functional labels, how pathway specific information such as motion and color are retained within different cortical circuits and the extent to which summation and surround suppression are represented within the population of identified neurons. Inhibitory neurons are thought to play specific roles in determining the emergent properties of V1 receptive fields such as orientation, direction and size selectivity. The extent or degree of tuning among the excitatory and inhibitory populations is unknown. Our third aim is to characterize inhibitory neurons in the input and infragranular layers of cortex. There are numerous disorders that are a result of structure-function abnormalities in cortical circuits including, amblyopia, epilepsy and schizophrenia. Understanding how the normal circuits operate provides opportunities for understanding neuronal abnormalities.

描述（由申请人提供）：了解皮层回路的组织方式及其功能是神经科学的核心目标。我们一直在研究初级视觉皮层 V1，以便了解它在视觉中的作用，同时也因为 V1 是大脑皮层中最容易理解的区域之一。一方面，我们通常对神经元的感受野特性有详细的了解，这些特性是根据 V1 中的神经元放电确定的，以及从细胞外记录获得的一系列视觉刺激。另一方面，通过解剖学研究，我们了解了 V1 内部以及 V1 与纹外皮层之间复杂的神经元结构和突触连接模式。我们的建议旨在弥合猴子初级视觉皮层回路中神经元结构与其感受野特性之间的差距。我们使用一种称为松散贴片近细胞记录的方法来监测细胞外动作电位，这使我们能够在功能上表征神经元的 RF，然后我们用示踪分子标记相同的神经元，随后恢复和重建三维树突和轴突乔木标记的神经元。 4a 层是来自外侧膝状核的大细胞传入神经的主要目标，为 4b 层提供输入。两层都有各种具有不同形态的神经元。这两层中还存在一系列感受野属性。我们的首要目标是表征 4ca 层和 4b 层的兴奋性神经元。我们将检验以下假设：存在与不同形态类型相关的不同功能特征。在第 6 层的锥体神经元中，根据其皮质内轴突树枝化的模式，有不同的神经元类别。轴突模式与第 4 层的 vi 和 P 细胞分裂相关。我们将使用功能测试，除了调整方向、空间频率、时间之外，还可以确定标记的神经元是否由大细胞或细细胞输入主导。我们的第二个目标是测试形态类别在多大程度上具有特定的功能标签，运动和颜色等通路特定信息如何保留在不同的皮质回路中，以及求和和周围抑制在群体中的表示程度。已确定抑制性神经元被认为在确定 V1 感受野的新兴特性（例如方向、方向和大小选择性）方面发挥着特定作用。我们的第三个目标是表征抑制性神经元的特征。皮质输入层和颗粒下层的神经元皮质回路的结构功能异常导致许多疾病，包括弱视、癫痫和精神分裂症。了解正常回路如何运作为了解神经元异常提供了机会。