An Investigation of the Neural Components and Saccade Sequences that Enable Direct Navigation through Virtual Space

Spatial navigation is a critical behavior for nearly all life forms. The ability to navigate to a destination and to remember how to return to that destination involves numerous brain processes such as perception, attention, memory, learning, proprioception, and distance estimation. The study of spatial navigation, in various organisms and on different sorts of maze-apparatuses, has revealed what is required of the brain and what is required of the environment to enable successful navigation. This dissertation adds to this vast literature by examining the physiological and behavioral components involved in human navigation in a virtual environment. The primary aim of this dissertation is to use the virtual Morris water task (vMWT) to distinguish how eye gaze patterns, frontal- parietal neural oscillations, and navigation path trajectories differ between participants who learn to take direct paths to the hidden escape platform compared to participants that use non-direct strategies to reach the platform. The vMWT is a virtualization of the Morris water task that is used with rats to find a hidden escape platform within a circular pool of water. While the vMWT has been used extensively and demonstrated sufficient translational value, there is still the specific remaining question of what physiological signals correlate with direct navigation in the virtual domain and how these physiological signals change as a function of learning. The final two aims of this dissertation build upon this initial investigation by 1) examining if these difference in learning can be generalized to other mazes or explained by other factors such as sex and motivation, 2) if a manipulation of viewing perspective can impact navigation performance and how this sort of manipulation is represented in the brain. Together these three aims demonstrate how the differences in navigation strategy within the virtual domain co-occur with differences in eye-gaze, neural-oscillations and path trajectory. Specifically, evidence will be provided as to how direct navigators in the vMWT 1) exhibit higher ERP amplitude at FCz upon finding the platform, 2) preferentially gaze at the distal cue closest to the hidden platform during last block of training, 3) utilize a saccade sequence pattern between the pool wall and pool water to calculate distance vector information, 4) have higher NT170 amplitude upon right turns to the reinforced alley of the T-maze, and 5) exhibit different theta and alpha/mu power spectra during artificial changes to viewing perspective