One-shot entorhinal maps enable flexible navigation in novel environments.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Animal Behavior

Background:

• Mammalian navigation relies on grid cells in the medial entorhinal cortex to form neural spatial maps.
• The rapid adaptation of grid cell firing patterns to environmental changes on a behaviorally relevant timescale is not well understood.

Purpose of the Study:

• To investigate how grid cell firing patterns adapt in real-time to novel or altered environmental features.
• To understand the role of visual landmarks in stabilizing grid cell network activity.
• To explore how behavioral adaptation occurs despite distortions in grid cell firing patterns.

Main Methods:

• Recording neural activity from over 15,000 grid cells in mice navigating virtual environments.
• Manipulating environmental features and observing real-time changes in grid cell firing.
• Utilizing a computational model to predict grid cell network responses.
• Employing a medial entorhinal cortex-dependent behavioral task.

Main Results:

• Visual landmarks provide fixed inputs to the grid cell network, enabling stable firing patterns after single exposures.
• Alterations in landmarks induce predictable distortions in grid cell firing patterns.
• Behavioral adaptation to landmark changes occurs via downstream plasticity, independent of immediate grid cell map distortions.

Conclusions:

• The brain balances navigational rapidity and accuracy by integrating fixed landmark inputs with downstream synaptic plasticity.
• Fixed connections between landmarks and grid cells allow quick spatial map generation for novel environments.
• Plasticity in downstream regions refines spatial maps for accurate environmental representation, demonstrating a broader neural principle of network connectivity.