Genetic variation in brain-derived neurotrophic factor and human fear conditioning

Area of Science:

• Neuroscience
• Genetics
• Psychology

Background:

• Brain-derived neurotrophic factor (BDNF) is vital for learning and memory.
• The BDNF Val66Met polymorphism influences hippocampal structure and function.
• BDNF also plays a role in amygdala-dependent associative learning in animal models.

Purpose of the Study:

• To investigate the association between the BDNF Val66Met polymorphism and human fear conditioning.
• To examine how genetic variations in BDNF affect amygdala-dependent associative learning.

Main Methods:

• Fifty-seven participants were genotyped for the BDNF Val66Met polymorphism.
• A differential fear conditioning paradigm was employed, involving conditioned stimuli (CS+) and varying shock probabilities.
• Fear conditioning was quantified using eye blink startle response and shock likelihood ratings.

Main Results:

• All participants perceived shock likelihood based on stimulus similarity to the CS+.
• Val/Val individuals exhibited potentiated startle responses to the CS+.
• Met allele carriers displayed deficient fear conditioning, with attenuated startle responses to the CS+.

Conclusions:

• BDNF genotype variation is linked to altered fear conditioning.
• Findings align with animal studies on BDNF's role in amygdala-dependent associative learning.
• Genetic variations in BDNF may represent a risk factor for psychopathology due to associative learning deficits.