The correlation between abnormal metabolism in anterior cingulum cortex and executive dysfunction with major depression patients before and after antidepressant treatment

Abstract

Objective To investigate neuro-biochemical changes of bilateral anterior cingulate cortex (ACC) in the patients with major depressive disorder (MDD) and the correlation between abnormal metabolism and the cognitive function before and after treatment. Methods Fifteen patients with major depression and 15 age-, sex- and education-matched healthy controls (HC) were involved. The neurochemical abnormalities including the levels of N-acetylaspartate (NAA), choline-containing compounds, glutamate/glutamine and myoinostol were measured by single-voxel proton magnetic resonance spectroscopic (1H-MRS). The subjects were then assessed with executive function with neuropsychological tests including Wisconsin cards sorting test (WCST), verbal fluency Task (vF), StrooP Color and Word Test(SCWT). After this, the patients took selectivity serotonin reuptake inhibitors (SSRIs) for eight weeks. Then, we examined the changes in NAA, Cho, Glx and MI in ACC of patients and assessed their executive function with the neuropsychological tests again. Results 1) In ACC, baseline NAA((7.36±1.67)mmol/L), GLx((11.68±1.65)mmol/L) and MI levels ((5.28±0.66)mmol/L)were significantly lower in MDD compared to those of HC(NAA(9.27±1.37)mmol/L、Glx(15.20±1.91)mmol/L、MI(7.80±2.73)mmol/L)(P<0.01); After treatment, the NAA ((9.34±2.45)mmol/L)and Glx ((16.79±3.96)mmol/L)increased significantly after treatment compared to those prior to pretreatment(NAA(7.36±1.67)mmol/L, Glx(11.68±1.65)mmol/L, P<0.05).2) The normal controls exhibited better in Performance of WCST and Performance of completion time of SCWT than our MDD patients (P<0.05 or P<0.01). The patients made significant improvements in Performance of WCST and completion time of SCWT(C form) after treatment (P<0.05 or P<0.01). 3) In post-treatment MDD, the ACC Glx level was significantly positively correlated with the categories completes of WCST (r=0.739, P=0.009) and inversely related with the numbers to complete the first categories of WCST (r=-0.699, P=0.017) and the completion time of SCWT(C form) (r=-0.651, P=0.030); elevated MI(r=-0.705, P=0.023)and NAA(r=-0.735, P=0.010)levels in ACC of post-treatment MDD were both negatively correlated with the numbers to complete the first categories of WCST. Conclusion The ACC may be a key region involved in antidepressant treatment in MDD. The increased ACC NAA, Glx and MI in MDD after treatment may be significantly correlated with the improve of executive function. Key words: Major depressive disorder; Anterior cingutate; Magnetic resonance spectroscopy; Executive dysfunction