Representations of directions and spatial memory in human neural oscillations and behavior

Spatial navigation and memory are core activities for humans. To perform these processes, the human brain represents spatial features of the surrounding environment (e.g. place, head direction, goal location) and of spatial activity within it (e.g. movement, speed, distance, grid). These representations can be seen on many different levels - ranging from micro signals in single cell recordings to macro signals in fMRI. In this talk I will focus on a third level of these representations which can be found in neural oscillations recorded via Intracranial electroencephalography in human patients, while the patients performed virtual spatial memory tasks. I will present the existing oscillatory signals, including a recent signal we found for grid-like representations, hexadirecitonal modulation of oscillatory power in the theta band (5-8Hz), which is linked to spatial memory. I will present these signals’ anatomical prevalence, theories for their underlying basis and their relation to other levels of neural representation, and the way these signals are modulated by external perceptual input (e.g. navigating virtually with different levels of fog) and by internal idiothetic input (e.g. navigating in the real world with Augmented Reality). I will conclude with discussing how these mesoscale signals bridge connect to other levels of neural representations and to human behavior, and the potential of spatial representations in general as a mechanistic basis for novel biomarkers and therapeutic targets for diseases causing spatial disorientation or memory impairments.