Experimental neuropsychological investigation of neural network dysfunctions in major depression

Previous fMRI studies have investigated specific working memory subcomponents subserved by different neuronal networks in healthy individuals (1–4). The aim of the present study was to identify specific dysfunctions of these neuronal networks in patients with major depression. 19 depressive patients and 19 healthy control subjects, matched with respect to gender, age, and educational status, underwent experimental neuropsychological testing using the same experimental paradigms as in the abovementioned studies. Patients differed significantly from healthy controls only in the verbal rehearsal task. 8 patients performed worse than 1.5 standard deviations from the mean value of the percentage of correct answers in the control group. There was no correlation between psychopathological rating scales and experimental test results. In summary, depressive patients displayed significant and specific deficits in the verbal rehearsal task. These findings suggest that the functional integrity of the verbal rehearsal mechanism may be disturbed in patients with major depression.