Genetic influence on functional brain activation to an affective face matching task: an fMRI twin-study.

Neural activations in response to pictures of faces have consistently been reported across a network of brain regions, including the lateral occipital face area, fusiform face area, superior temporal sulcus and the amygdala. Face-related activations in this network can be altered in anxiety conditions such as social anxiety disorder, but it is not known to what extent genetic factors influence the neural underpinnings of facial emotion recognition. We used the Hariri affective face matching task and functional magnetic resonance imaging to measure neural responses to negative (angry and fearful) facial-emotion categories in 64 pairs of monozygotic and 71 pairs of dizygotic healthy same sex twin pairs. Brain responses to negative faces were parcellated into 294 cytoarchitectonic regions according to the Jülich Brain Atlas. The variance in neural activation was then decomposed into additive genetic variance, common environmental factors, and specific environmental factors plus error measures (ACE model) in each region. The relationship between social anxiety, indexed by the Liebowitz Social Anxiety Scale (LSAS-SR), and brain activity was also assessed. Results were Bonferroni-corrected to control for false positives (p < 0.05). We found a small to moderate genetic influence on face-evoked neural responses in the amygdala, the lateral occipital face area, and the fusiform face area. There was a moderate genetic influence on social anxiety symptoms but individual differences in social anxiety did not predict brain activation. These findings demonstrate that genetic factors influence functional brain responses to faces expressing negative affect, as well as social anxiety traits, but the results do not provide evidence for shared genetic architecture between social anxiety symptomatology and neural responsiveness to negative facial emotions.