Cross-frequency coordination in a hippocampo-cortical circuit during probabilistic reversal learning.

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Adaptive decision-making under uncertainty relies on detecting environmental changes.
• The interplay between the hippocampus and cortex is crucial for flexible choice strategies.

Purpose of the Study:

• To investigate hippocampo-cortical circuit dynamics during probabilistic choice behavior.
• To identify neural markers of performance adaptation in a changing environment.

Main Methods:

• Rats performed a two-armed bandit task with uncued reward reversals.
• Local field potentials were recorded from dorsal hippocampus (CA1d), lateral entorhinal cortex (LEC), and prefrontal cortex (PFC).
• Model-free indices and mixed-effects modeling quantified performance and neural activity.

Main Results:

• Cortical synchrony in theta and fast-gamma bands negatively correlated with task performance.
• Hippocampal theta coordinated cortical gamma bursts and modulated spike timing across hippocampo-cortical pathways.
• Distinct neural activity patterns were observed during goal approach, including sustained PFC ramping and transient hippocampal/entorhinal suppression.

Conclusions:

• Session-averaged LEC-PFC connectivity in theta and gamma bands serves as a performance marker.
• Hippocampal theta orchestrates cortical gamma oscillations and neural synchrony for adaptive decision-making.
• This study provides a circuit-level framework for understanding decision-making under uncertainty.