Evidence for grid-cell-like activity in the time domain

Area of Science:

• Neuroscience
• Cognitive Science
• Computational Neuroscience

Background:

• Grid cells are fundamental to spatial navigation in mammals.
• Emerging evidence suggests grid cells also organize conceptual knowledge in humans.
• The role of grid-cell-like representations in temporal processing remains largely unexplored.

Purpose of the Study:

• To investigate whether grid-cell-like neural representations support the processing of temporal information.
• To examine the brain's mechanisms for mentally simulating trajectories through abstract 'age-day' space.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to monitor brain activity.
• Participants mentally simulated changes in age and time-of-day, creating trajectories in an abstract age-day space.
• Analysis focused on identifying grid-cell-like representations and their modulation by temporal orientation.

Main Results:

• Grid-cell-like representations were found to support mental navigation through the abstract age-day space.
• Brain regions involved in past-to-future orientation modulated the strength of grid-cell-like activity in the left entorhinal cortex.
• Findings indicate a significant interplay between spatial and temporal processing in the brain.

Conclusions:

• Temporal processing, including mental simulation of time, may be supported by neural systems primarily known for spatial functions.
• Abstract domains, like time, can influence and be organized by grid-cell-like representations, akin to spatial geometry.
• This research bridges the understanding of how the brain integrates spatial and temporal information, with implications for cognitive neuroscience.