High-dimensional mapping of the hippocampus in depression.
OBJECTIVE
Abnormalities of the hippocampus may play a role in the pathophysiology of depression, but efforts to identify a structural abnormality in this brain structure among depressed patients have produced mixed results. Previous research may have been limited by exclusive reliance on measures of hippocampal volume. High-dimensional brain mapping is a new analytic method that quantitatively characterizes the shape as well as volume of a brain structure. In this study, high-dimensional brain mapping was used to evaluate hippocampal shape and volume in patients with major depressive disorder and healthy comparison subjects.


METHODS
By using magnetic resonance imaging, brain scans were obtained from 27 patients with major depressive disorder and 42 healthy comparison subjects. High-dimensional brain mapping generated a series of 10 variables (components) that represented hippocampal shape, and hippocampal volumes were also computed. Analysis of variance techniques were used to compare depressed patients and comparison subjects on hippocampal shape and volume.


RESULTS
While the depressed patients and comparison subjects did not differ in hippocampal volume, there were highly significant group differences in hippocampal shape. The two groups did not overlap on a discriminant function computed from a model comprising the 10 components. The pattern of hippocampal surface deformation in the depressed patients suggested specific involvement of the subiculum.


CONCLUSIONS
Patients with major depression may have structural abnormalities of the hippocampus that can be detected by analysis of hippocampal shape but not volume. A specific defect in the subiculum could have widespread effects throughout neurocircuits that appear to be abnormal in depression.
Posener
Joel A
JA
Department of Psychiatry, Washington University School of Medicine, Campus Box 8134, 660 South Euclid Ave., St. Louis, MO 63110, USA. posenerj@medicine.wustl.edu
Wang
Lei
L
Price
Joseph L
JL
Gado
Mokhtar H
MH
Province
Michael A
MA
Miller
Michael I
MI
Babb
Casey M
CM
Csernansky
John G
JG
D000328:Adult; D001927:Brain Diseases / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D003865:Major Depressive Disorder / Q000473:pathology / Q000503:physiopathology*; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D012016:Reference Values