Enhanced amygdala and medial prefrontal activation during nonconscious processing of fear in posttraumatic stress disorder: An fMRI study

• Published in: Human brain mapping 2008-05, Vol.29 (5), p.517-523
• Main Authors: Bryant, Richard A., Kemp, Andrew H., Felmingham, Kim L., Liddell, Belinda, Olivieri, Gloria, Peduto, Anthony, Gordon, Evian, Williams, Leanne M.
• Format: Article
• Language: English
• Subjects: Adult; amygdala; Amygdala - metabolism; Biological and medical sciences; Electrodiagnosis. Electric activity recording; fear; Fear - physiology; Female; fMRI; Humans; Image Processing, Computer-Assisted; Investigative techniques, diagnostic techniques (general aspects); Magnetic Resonance Imaging; Male; medial prefrontal cortex; Medical sciences; Nervous system; posttraumatic stress disorder; Prefrontal Cortex - metabolism; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Stress Disorders, Post-Traumatic - physiopathology; Unconscious (Psychology)
• ISSN: 1065-9471; 1097-0193
• DOI: 10.1002/hbm.20415

Biological models of posttraumatic stress disorder (PTSD) suggest that patients will display heightened amygdala but decreased medial prefrontal activity during processing of fear stimuli. However, a rapid and automatic alerting mechanism for responding to nonconscious signals of fear suggests that PTSD may display heightened rather than decreased MPFC under nonconscious processing of fear stimuli. This study used functional magnetic resonance imaging to examine blood oxygenation level‐dependent signal changes during nonconscious presentation (16.7 ms, masked) of fearful and neutral faces in 15 participants with PTSD and 15 age and sex‐matched healthy control participants. Results indicate that PTSD participants display increased amygdala and MPFC activity during nonconscious processing of fearful faces. These data extend existing models by suggesting that the impaired MPFC activation in PTSD may be limited to conscious fear processing. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.