Human Hippocampal Mechanisms of Goal-directed Navigation

The rodent hippocampus is dominated by 6-12Hz theta band oscillations throughout translational movement. Both the frequency and power of theta rhythmicity increase with running speed, suggesting that theta oscillations encode information about self-motion to support navigation by path integration. In humans, invasive and non-invasive electrophysiology studies have reported similar increases in hippocampal theta power during movement in both real and virtual environments. In this talk, I will describe several studies in which we have used intracranial EEG and MEG to explore the behavioural correlates of oscillatory activity in the medial temporal lobe during spatial navigation. In particular, I will present evidence that hippocampal theta power and theta-gamma phase-amplitude coupling encode the length of upcoming paths during spatial planning, and that theta power covaries with perceived danger in anxiogenic environments. I will briefly describe how these signals are disrupted in people with Schizophrenia, and outline our future plans to assay neural representations of specific locations in the human brain.