title: Anterior cingulate, gyrus rectus, and orbitofrontal abnormalities in elderly depressed patients: an MRI-based parcellation of the prefrontal cortex.
abstract: OBJECTIVE
  To examine structural abnormalities in subregions of the prefrontal cortex in elderly patients with depression, the authors explored differences in gray matter, white matter, and CSF volumes by applying a parcellation method based on magnetic resonance imaging (MRI).
  
  
  METHODS
  Twenty-four elderly patients with major depression and 19 group-matched comparison subjects were studied with high-resolution MRI. Cortical surface extraction, tissue segmentation, and cortical parcellation methods were applied to obtain volume measures of gray matter, white matter, and CSF in seven prefrontal subregions: the anterior cingulate, gyrus rectus, orbitofrontal cortex, precentral gyrus, superior frontal cortex, middle frontal cortex, and inferior frontal cortex.
  
  
  RESULTS
  Highly significant bilateral volume reductions in gray matter were observed in the anterior cingulate, the gyrus rectus, and the orbitofrontal cortex. Depressed patients also exhibited significant bilateral white matter volume reductions and significant CSF volume increases in the anterior cingulate and the gyrus rectus. Finally, the depressed group showed significant CSF volume reductions in the orbitofrontal cortex relative to the comparison subjects. None of the other regions examined revealed significant structural abnormalities.
  
  
  CONCLUSIONS
  The prominent bilateral gray matter deficits in the anterior cingulate and the gyrus rectus as well as the orbitofrontal cortex may reflect disease-specific modifications of elderly depression. The differential pattern of abnormalities detected in the white matter and CSF compartments imply that distinct etiopathological mechanisms might underlie the structural cortical changes in these regions.
authors.affiliation: Department of Neurology, UCLA Neuropsychiatric Institute, David Geffen School of Medicine, Los Angeles, CA 90024, USA.
authors.forename: Martina
authors.initials: M
authors.lastname: Ballmaier
authors.forename: Arthur W
authors.initials: AW
authors.lastname: Toga
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Blanton
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Sowell
authors.forename: Helen
authors.initials: H
authors.lastname: Lavretsky
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Peterson
authors.forename: Daniel
authors.initials: D
authors.lastname: Pham
authors.forename: Anand
authors.initials: A
authors.lastname: Kumar
mesh_terms: D000368:Aged; D001921:Brain / Q000002:abnormalities*; D003865:Major Depressive Disorder / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006179:Gyrus Cinguli / Q000002:abnormalities; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D009915:Orbit; D017397:Prefrontal Cortex / Q000002:abnormalities