Prefrontal default-mode network interactions with posterior hippocampus during exploration.

Area of Science:

• Neuroscience
• Cognitive Science
• Decision Making

Background:

• The hippocampus and ventral prefrontal cortex (vPFC) are crucial for spatial navigation and value-based decision-making.
• Understanding how these regions interact to balance exploration and exploitation is key to deciphering foraging behavior.

Purpose of the Study:

• To investigate the neural mechanisms underlying the balance between exploration and exploitation in a continuous foraging task.
• To examine the roles of hippocampal-vPFC interactions in adapting behavior to varying reward landscapes.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure brain activity in participants foraging in a simulated environment.
• Reinforcement learning modeling was employed to analyze behavioral strategies and neural responses.
• Replication of findings was confirmed through out-of-session and out-of-sample experiments.

Main Results:

• Activity in the hippocampus and default network vPFC subregions correlated with the spatial distribution of rewards (value landscape).
• Higher activity was observed in the prefrontal default network and hippocampus in simpler, easily exploitable landscapes.
• Increased vPFC-hippocampal connectivity and synchronization between the prefrontal default network and posterior hippocampus were associated with greater behavioral exploration in uncertain landscapes.

Conclusions:

• Hippocampal and vPFC activity, particularly within the default network, are modulated by reward landscape complexity.
• Coordinated activity between the prefrontal default network and the posterior hippocampus facilitates exploration by integrating value representations with spatial maps.
• These findings elucidate the neural basis for adaptive foraging strategies, balancing seeking new information with exploiting known rewards.