Deactivation of the limbic system during acute psychosocial stress: evidence from positron emission tomography and functional magnetic resonance imaging studies.
BACKGROUND
Stress-induced metabolic changes can have detrimental health effects. Newly developed paradigms to investigate stress in neuroimaging environments allow the assessment of brain activation changes in association with the perception of and the metabolic response to stress.


METHODS
We exposed human subjects to a psychosocial stressor in one positron emission tomography (n = 10) and one functional magnetic resonance imaging (fMRI; n = 40) experiment.


RESULTS
We observed a profound deactivation of limbic system components including hippocampus, hypothalamus, medio-orbitofrontal cortex and anterior cingulate cortex in subjects who reacted to the stressor with a significant increase of the endocrine stress marker cortisol. Further, in the fMRI study, the degree of deactivation in the hippocampus was correlated with the release of cortisol in response to the stress task.


CONCLUSIONS
The observed deactivation of limbic system structures suggests elevated activation at rest and during nonstressful situations. A model is proposed where the observed reduction in limbic system activity is essential for the initiation of the stress response.
Center for Studies on Human Stress, Douglas Hospital Research Center and Montreal Neurological Institute, Department of Psychiatry, McGill University, Montreal, Quebec, Canada. jens.pruessner@mcgill.ca
Jens C
JC
Pruessner
Katarina
K
Dedovic
Najmeh
N
Khalili-Mahani
Veronika
V
Engert
Marita
M
Pruessner
Claudia
C
Buss
Robert
R
Renwick
Alain
A
Dagher
Michael J
MJ
Meaney
Sonia
S
Lupien
D000328:Adult; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008032:Limbic System / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D049268:Positron-Emission Tomography / Q000379:methods*; D013315:Stress, Psychological / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*
D010100:Oxygen; D006854:Hydrocortisone