Brain-derived neurotrophic factor val66met polymorphism and hippocampal activation during episodic encoding and...

Area of Science:

• Neuroscience
• Genetics
• Cognitive Psychology

Background:

• Brain-derived neurotrophic factor (BDNF) is crucial for neuronal survival, growth, and synaptic plasticity.
• The BDNF val66met polymorphism affects BDNF secretion and has been linked to memory performance and hippocampal activity.
• Previous research suggests met carriers have poorer episodic memory and reduced medial temporal lobe (MTL) activation, but findings lack replication and control for cognitive performance.

Purpose of the Study:

• To investigate the role of the BDNF val66met genotype on neural activity during episodic memory encoding and retrieval.
• To control for cognitive performance to clarify the relationship between the BDNF genotype and MTL activation.

Main Methods:

• Participants were genotyped for the BDNF val66met polymorphism.
• Functional magnetic resonance imaging (fMRI) was used to measure MTL activation during item and relational memory tasks.
• Cognitive performance on memory tasks was assessed and controlled for.

Main Results:

• Met carriers exhibited significantly increased MTL activation during both memory encoding and retrieval phases compared to noncarriers.
• This increased activation was observed across both item and relational memory tests.
• Cognitive performance was comparable between met carriers and noncarriers when controlling for task difficulty.

Conclusions:

• The BDNF val66met genotype is associated with altered neural recruitment in the MTL during episodic memory tasks.
• Met carriers can engage compensatory MTL mechanisms to achieve successful memory performance.
• Observed cognitive deficits in prior studies may not be an inherent effect of the BDNF val66met genotype but could be influenced by task demands or other factors.