BDNF Val⁶⁶Met polymorphism tunes frontolimbic circuitry during affective contextual learning

Area of Science:

• Neuroscience
• Genetics
• Cognitive Science

Background:

• Adaptive learning deficits are prevalent in various cognitive and behavioral disorders.
• The neurogenetic underpinnings of human affective learning remain largely unexplored.

Purpose of the Study:

• To investigate the neurogenetic mechanisms of affective learning using a higher-order contextual learning task.
• To examine the association between the BDNF Val⁶⁶Met polymorphism and frontolimbic brain activity during affective learning.

Main Methods:

• A higher-order contextual learning task involving emotional cue association and monetary outcomes.
• Genotyping participants for the BDNF Val⁶⁶Met polymorphism.
• Functional magnetic resonance imaging (fMRI) to measure blood oxygenation level dependent (BOLD) reactivity in frontolimbic regions.

Main Results:

• BDNF Val⁶⁶Met genotype modulated frontolimbic BOLD reactivity across learning, decision-making, and outcome phases.
• Met carriers exhibited reduced ventromedial prefrontal cortex (vmPFC) response to affective cues compared to Val homozygotes.
• Met carriers showed altered dorsolateral prefrontal cortex (dlPFC) activity related to decision difficulty and enhanced vmPFC reactivity during loss avoidance.

Conclusions:

• The BDNF Val⁶⁶Met polymorphism is linked to functional alterations in frontolimbic circuitry during complex affective learning.
• Specific alterations include modulated vmPFC and dlPFC responses, impacting affective cue processing and decision-making under uncertainty.
• These findings highlight the role of BDNF genotype in shaping neural mechanisms of adaptive learning and emotional regulation.