This 2019 German human study found:
- High BDNF methylation rates were for the first time shown to be associated with a high reactivity in the amygdala; and
- High BDNF methylation and high amygdala reactivity were associated with low novelty seeking.
There was no interaction or main effect of the Val66Met polymorphism on amygdala reactivity.
Our data adds evidence to the hypothesis that epigenetic modifications of BDNF can result in an endophenotype associated with anxiety and mood disorders. However, since correlations do not prove causality:
- A direct link between human BDNF mRNA/protein levels, methylation, amygdala reactivity and psychiatric disorders is still missing, demanding further research.
- Determining the underlying directions of the relations between BDNF methylation, amygdala reactivity, and NS [novelty seeking] cannot be accomplished based on our data and must await further research.
The fact that our results mainly involve the right amygdala is in line with previous studies. Recent reviews suggest a general right hemisphere dominance for all kinds of emotions, and, more specifically, a critical role of the right amygdala in the early assessment of emotional stimuli.
The experimental fMRI paradigm utilized a face‐processing task (faces with anger or fear expressions), alternating with a sensorimotor control task. Harm avoidance, novelty seeking, and reward dependence were measured using the Tridimensional Personality Questionnaire.”
https://onlinelibrary.wiley.com/doi/full/10.1002/hbm.24825 “The role of BDNF methylation and Val 66 Met in amygdala reactivity during emotion processing”