title: Biophysical changes in normal-appearing white matter and subcortical nuclei in late-life major depression detected using magnetization transfer.
abstract: Neuroanatomical changes have been identified in patients diagnosed with late-life major depressive disorder (MDD) compared with controls. These primarily comprise a decrease in focal brain volumes and an increase in MRI-determined high intensity lesions that are largely confined to the white matter. The physiological status of normal-appearing white matter in patients with MDD remains unknown. Magnetization transfer (MT) is a relatively new neuroimaging technique that permits us to examine the biophysical characteristics of specific brain regions. Using MT, we studied eight patients with late-life MDD and eight non-depressed controls. MT ratios (MTR), which reflect the integrity of the macromolecular protein pool, were ascertained in normal-appearing white matter and subcortical nuclei. Patients had significantly lower MTRs in the genu and splenium of the corpus callosum, the right caudate nucleus and putamen, and the occipital white matter compared with controls. The findings indicate that the structure of the macromolecular protein matrix may be compromised in normal-appearing white matter and critical subcortical nuclei in patients with late-life major depression. These changes may provide important substrates to mood disorders and have implications for neuronal connectivity and its role in the pathophysiology of late-life depression.
authors.affiliation: Department of Psychiatry C9-938, Neuropsychiatric Institute, 760 Westwood Plaza, Los Angeles, CA 90024, USA. akumar@mednet.ucla.edu
authors.forename: Anand
authors.initials: A
authors.lastname: Kumar
authors.forename: Rakesh C
authors.initials: RC
authors.lastname: Gupta
authors.forename: M
authors.initials: M
authors.lastname: Albert Thomas
authors.forename: Jeffry
authors.initials: J
authors.lastname: Alger
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Wyckoff
authors.forename: Sun
authors.initials: S
authors.lastname: Hwang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001284:Atrophy; D055592:Biophysical Phenomena; D001703:Biophysics; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D001931:Brain Mapping; D002421:Caudate Nucleus / Q000473:pathology / Q000503:physiopathology; D003337:Corpus Callosum / Q000473:pathology / Q000503:physiopathology; D003711:Demyelinating Diseases / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D046911:Macromolecular Substances; D008279:Magnetic Resonance Imaging; D008297:Male; D008606:Mental Processes / Q000502:physiology; D009185:Myelin Proteins / Q000032:analysis; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D009778:Occipital Lobe / Q000473:pathology / Q000503:physiopathology; D011699:Putamen / Q000473:pathology / Q000503:physiopathology; D012016:Reference Values
chemical_list: D046911:Macromolecular Substances; D009185:Myelin Proteins; D009419:Nerve Tissue Proteins