Morphometric analysis of amygdla and hippocampus shape in impulsively aggressive and healthy control subjects.
BACKGROUND
Impulsive aggressive behavior is thought to be facilitated by activation of the limbic brain, particularly the amygdala and hippocampus., Functional imaging studies suggest abnormalities in limbic brain activity during emotional information processing in impulsively aggressive subjects with Intermittent Explosive Disorder (IED). It is not known if IED is associated with altered amygdala and hippocampus volume and shape.


METHODS
We examined the volume and shape of the amygdala-hippocampal complex, using morphometric analysis of high resolution structural 3T MR scans in healthy control (HC: n = 73) subjects without history of Axis I or II psychiatric conditions and in subjects with IED (n = 67).


RESULTS
While no volume differences were observed between HC and IED subjects, a significant level of morphometric deformation, suggestive of cell loss, in both amygdala and hippocampal structures was observed bilaterally in IED subjects. Analysis of a canonical variable that used the first 10 eigenvectors from both sides of the brain revealed that these morphometric deformations in the IED subjects were not due the presence of confounding variables or to comorbidities among IED subjects.


CONCLUSIONS
These data reveal that IED is associated with a significant loss of neurons in both the amygdala and hippocampus. These changes may play a role in the functional abnormalities observed in previous fMRI studies and in the pathophysiology of impulsive aggressive behavior.
Clinical Neuroscience & Psychopharmacology Research Unit, Department of Psychiatry and Behavioral Neuroscience, University of Chicago, USA. Electronic address: ecoccaro@bsd.uchicago.edu.
Emil F
EF
Coccaro
Clinical Neuroscience & Psychopharmacology Research Unit, Department of Psychiatry and Behavioral Neuroscience, University of Chicago, USA.
Royce
R
Lee
Department of Psychology, Temple University, USA.
Michael
M
McCloskey
Department of Psychiatry & Behavioral Science, Feinberg School of Medicine, Northwestern University, USA.
John G
JG
Csernansky
Department of Psychiatry & Behavioral Science, Feinberg School of Medicine, Northwestern University, USA; Department of Radiology, Feinberg School of Medicine, Northwestern University, USA.
Lei
L
Wang
D000328:Adult; D000374:Aggression; D000679:Amygdala / Q000473:pathology*; D015897:Comorbidity; D007174:Disruptive, Impulse Control, and Conduct Disorders / Q000150:complications / Q000453:epidemiology / Q000473:pathology*; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D007175:Impulsive Behavior; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics
Aggression; Amygdala; Hippocampus; IED