Name: Jon M. Starnes

Master’s Thesis Defense Meeting
Date: Friday, July 3, 2020
Time: 10:00 am
Location: https://bluejeans.com/1831681686

 
Advisor:
Thackery Brown, Ph.D. (Georgia Tech)
 
Thesis Committee Members:
Thackery Brown, Ph.D. (Georgia Tech)
Scott Moffat, Ph.D. (Georgia Tech)
Lewis Wheaton, Ph.D. (Georgia Tech)
 
Title: The Predictive Roles of MTL and Striatal Volumes and Navigation Strategy Preferences for Learning Converging and Diverging Routes

Abstract:

Successful navigation of the environment is dependent on hippocampal function, and cognitive-map-based navigation ability may vary as a function of hippocampal volume. However, not all environments depend exclusively on hippocampal function or volume. Humans show individual variation in navigation strategy and performance, which may be explained by individual differences in medial temporal lobe function, and behavioral factors like strategy preferences, map experience, and spatial ability. Navigator accuracy tenably benefits from using a mixture of place-based and response-based navigation strategies, flexibly switching between them depending on the demands of the environment. This experiment examined participant performance in learning to navigate converging routes, where the route space and memories overlap, and diverging routes where memories become distinct again. Hierarchical clustering of participant navigation performance was used to train a machine learning classifier that identified three distinct navigation behavior profiles. Volumetric analysis on the hippocampus, entorhinal cortex, and the right caudate was used to test for associations between these volumes and how each behavioral profile performed at converging and diverging route choices. The behavioral profiles differed in total hippocampal volume, the ratio of the entorhinal cortex to hippocampal volume, and sense of direction. Exploratory analysis also points to the potential links between these volumes and navigation accuracy at converging versus diverging route choices.