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Date of Award
Doctor of Philosophy (PhD)
The visual cortex is a densely-interconnected network of neurons, which receives sensory input from the early visual pathway, and represents information about the visual world in the resulting spatiotemporal activity patterns. These patterns are mediated by cortical interactions that span multiple spatial scales (i.e., neuron-neuron, neuron-population, and population-population). Such interactions are a fundamental property of cortical function, and capture the contribution of the cortex to sensory coding. Yet these interactions are only beginning to be understood, in part because of the challenge of recording ongoing and visually-evoked activity across multiple spatial scales in individual studies. In this thesis, we present the results of such a study. Using the ex vivo turtle eye-attached whole-brain preparation, we simultaneously recorded the membrane potentials from pairs of cortical pyramidal neurons, as well as the nearby local field potential (LFP). In a parallel set of experiments, we recorded the LFP from multiple locations using a microelectrode array. To identify relevant cortical properties, we supplemented our experimental approach with network simulations. Our results quantify cortical interactions using a variety of coordination measures, and suggest that ongoing cortical activity, synaptic clustering, synaptic adaptation, and emergent network phenomena fundamentally shape the distribution and dynamics of coordination levels. Together, these results contribute to a clearer picture of cortical visual processing, and the roles of specific anatomical and emergent cortical properties in network function.
Chair and Committee
Anders Carlsson, Jim Miller, Woodrow Shew, Larry Snyder
Wright, Nathaniel Caleb, "Ongoing and Visually-Evoked Cortical Activity Measured Across Multiple Spatial Scales" (2016). Arts & Sciences Electronic Theses and Dissertations. 1014.
Available for download on Monday, December 21, 2020