Focal and lateralized subcortical abnormalities in unipolar major depressive disorder: an automated multivoxel proton magnetic resonance spectroscopy study.

Background: The results of prior proton magnetic resonance spectroscopy ((1)H-MRS) studies in unipolar major depressive disorder (MDD) evaluating choline (Cho)/creatine (Cr) and N-acetyl-L-aspartate (NAA)/Cr ratios are mixed. These single-voxel or one-dimensional chemical-shift imaging (CSI) nonautomated (1)H-MRS studies has been unable to evaluate global or lateralized abnormalities in neuronal or membrane function. Using automated multivoxel two-dimensional CSI (1)H-MRS techniques, we tested the hypothesis that patients with MDD have focal neuronal and membrane abnormalities localized in the subcortical region.

Hippocampal volume in geriatric depression.

Background: There is a growing literature on the importance of hippocampal volume in geriatric depression.

Methods: We examined hippocampal volume in a group of elderly depressed patients and a group of elderly control subjects (N = 66 geriatric depressed patients and 18 elderly nondepressed control subjects) recruited through Duke's Mental Health Clinical Research Center for the Study of Depression in the Elderly. The subjects received a standardized evaluation, including a magnetic resonance imaging scan of the brain.

Magnetic-resonance morphometry in patients with major depression.

Magnetic-resonance morphometry performed on 72 patients with major depression compared with 38 control subjects replicated previously reported, statistically significant reductions in the volumes of the caudate (P < 0.03) and putamen (P < 0.05) in depressed patients.

Optical transmembrane potential measurements during defibrillation-strength shocks in perfused rabbit hearts.

To study the optical transmembrane potential change (delta F) induced during shocks, optical recordings were obtained in 15 isolated perfused rabbit hearts treated with the potentiometric dye di-4-ANEPPS and diacetyl monoxime. Shock electrodes were sutured on the right and left ventricles. A laser beam 30 microns in diameter was used to optically excite di-4-ANEPPS.