DAT genotype modulates striatal processing and long-term memory for items associated with reward and punishment

Area of Science:

• Neuroscience
• Cognitive Psychology
• Genetics

Background:

• Appetitive motivation enhances episodic memory via the SN/VTA, striatum, and hippocampus.
• The role of dopaminergic mechanisms in processing both appetitive and aversive motivation and memory is not fully understood.

Purpose of the Study:

• To contrast the impact of aversive and appetitive motivation on episodic long-term memory.
• To investigate the modulation of motivational processing and memory by dopaminergic mechanisms using DAT gene polymorphisms.

Main Methods:

• Functional magnetic resonance imaging (fMRI) to study neural processing.
• Participants genotyped for the dopamine transporter (DAT) gene polymorphism.
• Careful matching of groups for the serotonin transporter (5-HTTLPR) gene polymorphism.

Main Results:

• Recognition memory for both appetitive and aversive cues was enhanced in DAT 10-repeat homozygotes compared to heterozygotes.
• 10-repeat homozygotes exhibited increased striatal activity during anticipation of motivational outcomes.
• Higher encoding activity in the striatum and hippocampus for recognized items was observed in 10-repeat homozygotes.

Conclusions:

• Dopaminergic mechanisms in the striatum are involved in processing both appetitive and aversive motivation.
• Dopamine plays a crucial role in memory encoding for motivational information.
• Motivational event encoding relies on dopaminergic processes in the hippocampus, consistent with animal studies.