Egocentric and Allocentric Spatial Coding in Cortex

项目摘要/摘要 这一新拨款中提出的项目解决了大脑皮层区域的空间编码特性。 空间位置的表征对于广泛的认知功能很重要，包括 目标导向导航的规划。这项资助提出了具体的实验来测试建模预测 关于存在以自我为中心的边界表示和与 大脑皮层结构中异地中心性空间表征的形成。 具体目标#1：记录脾后皮质和内嗅皮层的神经放电活动将测试 以自我为中心的大脑皮层区域必须编码环境边界位置的假设 坐标。这一预测源于边界的分心表示的形成模型。 它们需要来自以自我为中心、以视图为中心的环境边界编码的输入。实验将会 扩展这个实验室的初步数据，显示脾后皮质边界的自我中心编码。模型 显示了自我中心边界单元可以与头部方向输入相结合来编码异心边界 位置，它可以驱动空间位置的编码。进一步的实验将测试环境的影响 在内嗅皮质和精索后皮质的放电活动的界限，包括测试 操纵环境的形状，插入新的边界和不同的奖励位置， 在黑暗中记录，并按头部方向测试自我中心编码和分配中心编码的共存 细胞。这种对模型预测的实验测试将为建立我们的 理解认知加工的空间编码。 具体目标#2：记录脾后皮质和内嗅皮层的神经放电活动将测试 补充性假设认为，对跑步速度的编码也在生成 空间位置，以及跑步速度的编码在不同的时间进程中如何变化，以及可能取决于 来自边界的感官输入。实验将包括分析不同情况下的运行速度编码 内嗅皮层和脾后皮质的空间尺度从1秒到多分钟不等。时间 课程还将在实验中进行分析，以探索在以下情况下跑步速度表示的变化 障碍特征被黑暗遮挡住了。这一目标还包括以切片的形式记录整个细胞贴片 分析与电路动力学相关的本征尖峰活动的时间进程，以编码速度和 地点。最后，对内侧隔区特定神经元群体的光遗传失活将测试如何 输入调节内侧内嗅觉皮质神经元对空间位置和速度的编码。这些 实验将有助于我们理解构成形成的皮层回路的动力学。 对大脑皮层认知加工的许多方面都很重要的同心空间表征，包括 规划目标导向的行为。

PROJECT SUMMARY/ABSTRACT The projects proposed in this new grant address the properties of spatial coding in cortical regions. Representations of spatial location are important for a broad range of cognitive functions, including the planning of goal-directed navigation. This grant proposes specific experiments to test modeling predictions about the existence of egocentric representations of boundaries and coding of running speed relevant to the formation of allocentric spatial representations in cortical structures. Specific Aim #1: Recordings of the neural spiking activity in retrosplenial cortex and entorhinal cortex will test the hypothesis that cortical regions must code the position of environmental boundaries in egocentric coordinates. This prediction arose from models of the formation of allocentric representations of boundaries which require input from an egocentric, view-centered coding of environmental boundaries. Experiments will extend preliminary data from this lab showing egocentric coding of boundaries in retrosplenial cortex. Models show that egocentric boundary cells could be combined with head direction input to code allocentric boundary position, which can drive coding of spatial location. Further experiments will test the influence of environmental boundaries on spiking activity in the entorhinal cortex and retrospenial cortex, including testing the influence of manipulations of the shape of the environment, the insertion of new boundaries and different reward locations, recordings in darkness, and testing coexistence of egocentric coding with allocentric coding by head direction cells. This experimental testing of the predictions from models will provide an important link for building our understanding of the coding of space for cognitive processing. Specific Aim #2: Recordings of neural spiking activity in retrosplenial cortex and entorhinal cortex will test the complementary hypothesis that coding of running speed also plays a role in generation of representations of spatial location, and how the coding of running speed varies over different time courses and may depend on sensory input from boundaries. Experiments will include analysis of the coding of running speed at different spatial scales in entorhinal cortex and retrosplenial cortex ranging from one second to many minutes. The time course will also be analyzed in experiments exploring the change in running speed representations when barrier features are obscured by darkness. This aim also includes whole cell patch recording in slices to analyze the time course of intrinsic spiking activity relevant to the circuit dynamics for coding of speed and location. Finally, optogenetic inactivation of specific populations of neurons in medial septum will test how inputs regulate the coding of spatial location and speed by neurons in the medial entorhinal cortex. These experiments will contribute to our understanding of the dynamics of cortical circuits that underlie the formation of allocentric spatial representations important to many aspects of cortical cognitive processing, including the planning of goal-directed behavior.