The Role of LFP Spatial Structure in the Hippocampus

University Of California Berkeley, Berkeley CA

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Abstract

DESCRIPTION (provided by applicant): The long-term objective of this work is to understand how the activity of neurons is coordinated within the hippocampus, a brain region involved in the storage of memories. One manifestation of this coordination is the local field potential (LFP), the summed electrical activity of a small volume of neural tissue. Recently, multi- electrode arrays (MEAs) have enabled the simultaneous measurement of LFPs and single-neuron activity from multiple sites within the brain of an animal as it performs a task. This advance motivates the development of new computational methods that can identify the relationships that exist within these rich, large data sets. The temporal structure of hippocampal LFPs is known to correlate with single-neuron activity, as well as with behavioral state. In contrast, the spatial structure of these LFPs remains relatively unexplored. An interesting example of this spatial structure are the traveling LFP waves that propagate through the hippocampus. This project will examine whether the spatial dynamics of the hippocampal LFP influence neuronal activity and its relationship to behavior. Its aims are 1) to identify a parsimonious model for explaining the observed spatio- temporal structure in the LFP; 2) to investigate the relationship of LFP structure to single-neuron activity; and 3) to understand how LFP structure governs circuit-level neuronal processing within the hippocampus. To achieve these goals, this project will employ statistical learning techniques to extract spatio-temporal regularities from within the LFP, and use predictive models to examine the influence of different LFP structures on the population activity of hippocampal neurons. This work will identify concise metrics that capture the richness of high-dimensional hippocampal LFP measurements. Furthermore, it will examine the utility of incorporating complex dynamical features into current models of hippocampal processing. This work may help understand how distortions in electrical activity within the hippocampus lead to conditions such as epilepsy and amnesia. It will evaluate the suitability of the LFP as a direct target for neuroprosthetic interventions. Finally, it may lead to screening procedures for rapidly finding potential abnormalities in patients' brain activity, and help understand the implications of such abnormalities for patients' lifestyles.