Active maintenance of eligibility trace in rodent prefrontal cortex

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Decision Making

Background:

• Persistent neural activity is hypothesized to maintain eligibility traces for learning.
• Empirical evidence for active maintenance of these traces has been limited.

Purpose of the Study:

• To investigate the role of the medial prefrontal cortex (mPFC) in maintaining choice signals for temporal credit assignment.
• To provide direct evidence for active maintenance of eligibility traces.

Main Methods:

• Neuronal activity was recorded in the mPFC of rats performing a dynamic foraging task.
• The task required rats to remember choices over seconds for outcome-based credit assignment.

Main Results:

• mPFC neurons exhibited significant choice signals between action selection and outcome.
• Convergence of choice, outcome, and action value signals was observed in the mPFC upon outcome revelation.

Conclusions:

• The mPFC actively maintains choice signals via persistent neural activity, supporting temporal credit assignment.
• The mPFC may update action values by integrating maintained eligibility traces with outcome information.