Stangl, MatthiasDePasquale, BrianJiang, Daniel2025-05-232025-05-232025https://hdl.handle.net/2144/504812025Spatial navigation and memory retrieval are essential cognitive processes, supported by rhythmic patterns of brain activity known as neural oscillations. These oscillations occur at different frequencies, each believed to serve distinct cognitive functions: slower theta oscillations (approximately 2–8 Hz in humans) are known to associate with memory formation and spatial cognition, while faster gamma oscillations (approximately 30–90 Hz) support rapid, local neural processing in sensory and memory related tasks. A crucial form of interaction between these rhythms is oscillatory phase-amplitude coupling, a phenomenon in which the timing (phase) of slower-frequency brain waves controls the intensity (amplitude) of faster-frequency activity. In particular, theta–gamma coupling is largely thought to coordinate neural activity to enhance memory retrieval during stationary or virtual navigation tasks; however, it remains unclear whether similar mechanisms facilitate memory during real-world navigation involving complex movements and sensory integration. To address this gap, intracranial EEG signals are recorded from freely moving participants with chronically implanted electrodes as they performed a real-world navigation task. In this task, 'memory-guided navigation' required recalling hidden target locations from previous experience, whereas 'visually-guided navigation' relied on continuously available external cues. The present results show that memory-guided spatial navigation in humans is associated with a pronounced increase in phase-amplitude coupling between low-theta (1–3 Hz) and low-gamma (35–45 Hz) oscillations in the medial temporal lobe, compared to spatial navigation guided solely by visual cues. This finding expands previous evidence from stationary laboratory studies, suggesting that theta–gamma coupling specifically supports memory retrieval demands encountered during active, real-world navigation. More broadly, these results emphasize that coordinated neural rhythms are central not just in simplified experimental tasks but also during complex cognitive behaviors in everyday human life, highlighting potential neural markers relevant for studying memory impairments in neurodegenerative disorders.en-USAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Biomedical engineeringNeurosciencesHuman memoryiEEGMobile human imagingSpatial navigationThesis/Dissertation2025-05-220009-0002-4879-6397