Association between amygdala reactivity and a dopamine transporter gene polymorphism

Area of Science:

• Neuroscience
• Genetics
• Psychiatry

Background:

• The amygdala is crucial for processing external stimuli and fear.
• Dopamine (DA) modulates amygdala function.
• The dopamine transporter (DAT) regulates DA transmission via reuptake.

Purpose of the Study:

• To investigate if a variable number tandem repeat polymorphism in the DAT gene (SLC6A3) affects amygdala function during the processing of aversive emotional stimuli.

Main Methods:

• Positron emission tomography (PET) with [(15)O]water measured regional cerebral blood flow in a Swedish sample (32 social anxiety disorder patients, 17 healthy volunteers) exposed to angry and neutral faces.
• Blood oxygen level-dependent functional magnetic resonance imaging (fMRI) assessed amygdala reactivity in a US sample (85 healthy volunteers) exposed to threatening faces and neutral shapes.

Main Results:

• In both Swedish and US samples, individuals carrying the 9-repeat allele of the DAT polymorphism showed higher amygdala reactivity compared to 10-repeat homozygotes.
• This indicates a link between the DAT gene polymorphism and amygdala response to emotional stimuli.

Conclusions:

• The studied DAT gene polymorphism is associated with individual variability in amygdala reactivity.
• This genetic variation may play a role in the neural mechanisms underlying fear processing and emotional regulation.