EEG Correlates of Spatial Navigation in Patients with Right Hippocampal Lesion: A Mobile Brain/Body Imaging (MoBI) Study

Spatial navigation is a fundamental cognitive function that consists of different cognitive processes such as learning and decision making as well as physical locomotion. In the literature, there is a tendency to focus on cognitive elements of human spatial navigation while the presence of the body and embodied agents are neglected. Being that sensory and motor systems are integrated into the brain mechanisms according to embodied cognition theory, integrating physical movement into navigation research is crucial to investigate brain dynamics underlying human spatial navigation. Using Mobile Brain/Body Imaging (MoBI) approach, this study aims to understand electroencephalographic (EEG) activity during spatial navigation in actively moving humans. In the present study, 27 participants (9 patients with right hippocampal lesion and 18 healthy matched controls) performed a spatial navigation task in a human virtual analogue of the Morris Water Maze. Subjects were tested in both desktop and MoBI setups. In both study setups, frontal-midline (FM) theta (4-8 Hz) oscillations were examined with high-density EEG. In MoBI, EEG activity was recorded synchronously to motion capture, and the virtual environment was presented by a head-mounted display. EEG data were analyzed by using the event-related desynchronization/synchronization (ERD/ERS) method. Association between FM theta activity and spatial navigation performance was analyzed. Further, we also tested the effect of the study setup on the participant group. By comparing desktop and MoBI setups, the study aims to reveal how dynamics of the brain with hippocampal lesion change under action during spatial navigation compared to a healthy brain.