Effective connectivity of face and fear processing in juvenile myoclonic epilepsy

Individuals with Juvenile Myoclonic Epilepsy (JME) exhibit impaired facial emotion perception, especially regarding fear. However, the underlying neural mechanisms remain to be fully understood. Particularly, the connectivity between emotion-related regions, such as the amygdala, and visual face-processing areas, specifically the Fusiform Face Area (FFA), appears to be relevant for typical facial fear processing. We therefore explored the effective connectivity within the FFA-amygdala network in JME.

Fourteen individuals diagnosed with JME and 14 healthy controls matched for age, sex, and alexithymia (i.e., emotional awareness) participated in an fMRI face-viewing experiment. Participants were presented with images of neutral and fearful faces, as well as houses. Using Dynamic Causal Modelling, we examined endogenous connectivity, modulation by task conditions, and the influence of experimental inputs within the bilateral FFA-amygdala network (n = 24), incorporating both intra- and interhemispheric connections.

Compared to healthy controls, we found alterations mainly in the task-independent endogenous structure of the FFA-amygdala network in JME. The self-connection of the right amygdala was particularly enhanced, with the same tendency observed for the left amygdala and the right FFA. Furthermore, aberrations were indicated in the interhemispheric transfer between the amygdalae under the modulation of fear. Exploratory analyses revealed correlations of neural activity, and neural network parameters with both the onset and duration of epilepsy.

Overall, we found initial evidence of alterations in the FFA-amygdala network in JME. Particularly, the right amygdala showed a greater inhibitory self-connection, which suggests a generally reduced sensitivity to external input and might affect social and emotional processing. This emphasizes further exploring the network structure, its behavioural implications, and connectivity with other regions in larger samples.