CRCNS: Collaborative Research: How is Information Coded in Turtle Visual Cortex?

EIA-0218186 Ghosh，比霍伊·克华盛顿大学CRCNS：合作研究：信息是如何在海龟的视觉皮质中编码的？视觉刺激在淡水海龟的视觉皮质中唤起一种传播的活动波。初步研究表明，有关刺激在视觉空间的位置的信息编码在这些波的时空动态中。实际上，可能有一张视觉空间的地图来反映视觉皮质的动态。这一假设正在三个实验室的合作努力中得到验证。圣安东尼奥的大卫·森斯曼正在使用电压敏感染料方法记录视网膜上35个点的光斑所产生的波。这些研究将根据35个位点的刺激重复呈现来表征地图的特征。芝加哥的菲利普·乌林斯基正在开发海龟视觉路径的大规模模型。正在构建单个视网膜神经节细胞的模型，该模型结合了经典的基于过滤器的神经节细胞建模方法和神经节细胞的隔室模型。他们正被用来构建与这35个基因座匹配的35个模型视网膜斑块。目前正在对海龟外侧膝状复合体中神经元的生物物理学进行生理学研究。它们被用来建立外侧膝状体复合体的模型，这是模拟视网膜-膝状体-皮质通路的最后一步。圣路易斯的比霍伊·戈什正在开发精细的估计技术，这种技术允许根据皮质波的动力学来估计视觉刺激的位置。这项工作提供了所需的数学框架，以表征潜在的视觉空间图到波的动态。这项工作意义重大，因为它表征了一种在视觉皮质中编码信息的新方法，这种方法可能适用于哺乳动物和海龟的高级皮质区域。

EIA-0218186Ghosh, Bijoy KWashington UniversityCRCNS: Collaborative Research : How is Information Coded in Turtle Visual Cortex ?Visual stimuli evoke a propagating wave of activity in the visual cortex of freshwater turtles. Preliminary work suggested that information about the position of stimuli in visual space is coded in the spatiotemporal dynamics of these waves. Effectively, there may be a map of visual space to the dynamics of the visual cortex. This hypothesis is being examined in a collaborative effort involving three laboratories. David Senseman in San Antonio is using voltage sensitive dye methods to record the waves produced by presenting spots of light at 35 spots on the retina. These studies will characterize the features of the map based on repeated presentations of stimuli at 35 loci. Philip Ulinski in Chicago is developing a large-scale model of the visual pathway of turtles. Models of individual retinal ganglion cells that combine both classic filter-based approaches to modeling ganglion cells, with compartmental modeling of ganglion cells are being constructed. They are being used to construct 35 patches of a model retina that match the 35 loci. Physiological studies of the biophysics of neurons in the lateral geniculate complex of turtles are being carried out. They are used to develop a model of the lateral geniculate complex, which is the last step in modeling the retino-geniculate-cortical pathway. Bijoy Ghosh in St. Louis is developing refined estimation techniques that allow the position of a visual stimulus to be estimated from the dynamics of the cortical waves. This work is providing the mathematical framework needed to characterize a potential map of visual space to the dynamics of the wave. This work is significant because it is characterizing a novel method of coding information in visual cortex that may apply to higher order cortical areas in mammals, as well as turtles.