Effect of task conditions on brain responses to threatening faces in social phobics: an event-related functional magnetic resonance imaging study.
BACKGROUND
The aim of this study was to identify brain activation to socially threatening stimuli in social phobic subjects during different experimental conditions.


METHODS
With event-related functional magnetic resonance imaging, brain activation to photographs and schematic pictures depicting angry or neutral facial expressions was measured in social phobic subjects and healthy control subjects, while subjects assessed either emotional expression (angry vs. neutral; explicit task) or picture type (photographic vs. schematic; implicit task).


RESULTS
Compared with control subjects, phobics showed greater responses to angry than to neutral photographic faces in the insula regardless of task, whereas amygdala, parahippocampal gyrus, and extrastriate visual cortex were more strongly activated only during the implicit task. Phobics, in contrast to control subjects, showed similar activation patterns during both tasks. For schematic angry versus neutral faces, activation of insula and extrastriate visual cortex was found in phobics, but not in control subjects, during both tasks.


CONCLUSIONS
Differences between social phobics and control subjects in brain responses to socially threatening faces are most pronounced when facial expression is task-irrelevant. Phobics intensively process angry (photographic as well as schematic) facial expressions, regardless of whether this is required. The insula plays a unique role in the processing of threat signals by social phobics.
Straube
Thomas
T
Department of Biological and Clinical Psychology, Friedrich-Schiller-University, Am Steiger 3/1, D-07743 Jena, Germany. straube@biopsy.uni-jena.de
Kolassa
Iris-Tatjana
IT
Glauer
Madlen
M
Mentzel
Hans-Joachim
HJ
Miltner
Wolfgang H R
WH
D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000098:blood supply / Q000503:physiopathology*; D001931:Brain Mapping; D003213:Conditioning, Psychological / Q000502:physiology*; D004644:Emotions; D005071:Evoked Potentials / Q000502:physiology*; D005149:Facial Expression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010698:Phobic Disorders / Q000503:physiopathology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time