Theta oscillations coordinate grid-like representations between ventromedial prefrontal and entorhinal cortex

Area of Science:

• Neuroscience
• Cognitive Science
• Computational Neuroscience

Background:

• Grid cells and theta oscillations are key to the brain's navigation system, primarily studied in the entorhinal cortex (EC).
• Recent fMRI suggests grid-like representations exist in the human ventromedial prefrontal cortex (vmPFC), but their neural basis and interaction with EC grids remain unclear.

Purpose of the Study:

• To investigate the neural mechanisms of grid-like representations in the human vmPFC.
• To explore the interaction between vmPFC and EC grid activity during spatial navigation.

Main Methods:

• Intracranial electroencephalography (iEEG) recordings from epilepsy patients during a virtual spatial navigation task.
• Analysis of theta power oscillations and information transfer between vmPFC and EC.

Main Results:

• vmPFC theta power demonstrated sixfold rotational symmetry, synchronized with EC grid representations.
• Synchronous theta oscillations between vmPFC and EC predicted navigational performance.
• A unidirectional information flow from vmPFC to EC was observed during memory retrieval.

Conclusions:

• This study identifies the neural signature and functional role of grid-like representations outside the EC in humans.
• It highlights the synchronization of vmPFC and EC grids via theta oscillations as crucial for human spatial navigation and memory retrieval.