Episodic memory encoding interferes with reward learning and decreases striatal prediction errors.

Area of Science:

• Neuroscience
• Cognitive Science
• Decision Science

Background:

• The striatum and hippocampus are crucial for reward learning and episodic memory, respectively.
• These learning systems traditionally studied separately, likely interact during complex experiences.

Purpose of the Study:

• To investigate the interaction between incremental reward learning and episodic memory encoding.
• To understand how concurrent memory encoding influences reward-based decision-making.

Main Methods:

• Human participants made choices with variable reward probabilities while viewing incidental images.
• A surprise memory test assessed recall of these images the following day.
• Functional magnetic resonance imaging (fMRI) analyzed brain activity and connectivity during the task.

Main Results:

• Stronger episodic memory correlated with reduced influence of recent rewards on choices.
• Weaker striatal reward prediction error signals were observed with enhanced episodic memory.
• Increased hippocampal-striatal connectivity was linked to decreased reward prediction error signals.

Conclusions:

• Episodic memory encoding may compete with striatal processing for reward information.
• Interactions between memory and reward learning systems shape adaptive decision-making.