Genetic influences on central and peripheral nervous system activity during fear conditioning

Fear conditioning is an evolutionarily conserved type of learning serving as a model for the acquisition of situationally induced anxiety. Brain function supporting fear conditioning may be genetically influenced, which in part could explain genetic susceptibility for anxiety following stress exposure. Using a classical twin design and functional magnetic resonance imaging, we evaluated genetic influences (h(2)) on brain activity and standard autonomic measures during fear conditioning. We found an additive genetic influence on mean brain activation (h(2) = 0.34) and autonomic responses (h(2) = 0.24) during fear learning. The experiment also allowed estimation of the genetic influence on brain activation during safety learning (h(2) = 0.55). The mean safety, but not fear, related brain activation was genetically correlated with autonomic responses. We conclude that fear and safety learning processes, both involved in anxiety development, are moderately genetically influenced as expressed both in the brain and the body.

Automated summary

This study used a classical twin design and functional magnetic resonance imaging to evaluate the genetic influences on brain activity and autonomic responses during fear conditioning. The results showed that both mean brain activation and autonomic responses during fear learning were genetically influenced. The study also found a genetic influence on brain activation during safety learning. The mean safety-related brain activation was genetically correlated with autonomic responses, while fear-related brain activation was not.