a1 Institut d'Alta Tecnologia-PRBB, CRC Corporació Sanitària, Barcelona, Spain
a2 Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne, Australia
a3 Department of Electronic Engineering, Technical University of Catalonia, Spain
a4 Department of Clinical and Health Psychology, Autonomous University of Barcelona, Barcelona, Spain
a5 Clinical Sciences Department, Faculty of Medicine, University of Barcelona, Spain
a6 Department of Radiology, Hospital del Mar, Barcelona, Spain
a7 Department of Psychiatry, Bellvitge University Hospital, Barcelona, Spain
Background Social anxiety often involves a combination of hypervigilance and avoidance to potentially warning signals including the facial expression of emotions. Functional imaging has demonstrated an increase in amygdala response to emotional faces in subjects with social anxiety. Nevertheless, it is unclear to what extent visual areas processing faces influence amygdala reactivity in different socially anxious individuals. We assessed the influence of the fusiform gyrus activation on amygdala response to emotional faces in the non-clinical range of social anxiety.
Method Twenty-two normal subjects showing a wide range in social anxiety scores were examined using functional magnetic resonance imaging (fMRI) during the processing of happy and fearful faces. A dimensional analysis approach was used involving voxel-wise mapping of the correlation between subjects' social anxiety scores and amygdala activation, before and after controlling for fusiform gyrus activation.
Results We observed that only after controlling for subjects' level of activation of the fusiform gyrus was there an association between social anxiety ratings and amygdala response to both happy and fearful faces. The fusiform gyrus influence was more robust during the fear condition. Of note, fusiform gyrus response to fearful faces showed a negative correlation with additional behavioral assessments related to avoidance, including social anxiety scores, harm avoidance and sensitivity to punishment.
Conclusions Relevant interactions among the emotional face-processing stages exist in the non-clinical range of social anxiety that may ultimately attenuate amygdala responses. Future research will help to establish the role of this effect in a clinical context.
(Received December 07 2007)
(Revised November 13 2008)
(Accepted November 26 2008)
(Online publication January 21 2009)