Gray matter volume abnormalities were associated with sustained attention in unmedicated major depression

Impaired sustained attention seems to be a core feature of depression while the anatomical alteration of brain was widely reported in depression patients. The authors aimed to identify the relationship between anatomical brain changes and sustained attention deficits in unmedicated patients with major depressive disorder (MDD).

A total of 51 medication-free MDD patients and 51 matched healthy controls (HC) underwent high-resolution structural magnetic resonance imaging scanning, and optimized voxel-based morphometry method was performed to analyze the changes of gray matter volume (GMV). We employed a computerized neurocognitive task from the Cambridge Neuropsychological Tests Automated Battery (CANTAB)--Rapid Visual Information Processing (RVP) task--as a measurement of sustained attention. Based on clinical symptoms, 40 patients who had completed CANTAB-RVP test were divided into MDDa (mild depression patients) and MDDb (severe depression patients) groups. Then the relationships among sustained attention, GMV of different regions and clinical symptoms were explored separately.

MDD patients showed significant GMV increase in left posterior cingulate cortex (PCC) and inferior frontal gyrus (IFG) (p<0.001, uncorrected), and significant GMV decrease in medial/superior frontal gyrus (MFG/SFG) and lingual gyrus (p<0.001, uncorrected). Structure-cognition correlation analyses revealed that in MDD patients, GMV alterations of the IFG were significantly correlated with sustained attention as measured by the CANTAB-RVP.

Increased GMV values of IFG were associated with sustained attention which may underlie the pathophysiology of MDD or be part of the cognition circuit. In the severe depression patients, sustained attention deficits were positively correlated with clinical symptoms.