Difference in amplitude of low-frequency fluctuation between currently depressed and remitted females with major depressive disorder

• Compared low-frequency fluctuation in current and remitted depression.
• Right median frontal gyrus showed abnormality specific to current depression.
• Right putamen showed a trait-related marker to major depression.

Medical intervention for major depressive disorder (MDD) can be more appropriately focused through the identification and characterization of neurobiological markers that are specific to the disorder, and this study aims to examine the abnormality in the fractional amplitude of low-frequency fluctuation (fALFF) and the amplitude of low-frequency fluctuation (ALFF) in currently depressed and remitted female MDD patients and to correlate these fluctuations with clinical markers of MDD. Nineteen currently depressed female patients, 19 remitted female patients, as well as 19 age- and education-matched healthy females participated in the resting-state functional magnetic resonance imaging (fMRI) analysis. We compared the fALFF/ALFF maps among the three groups and investigated the correlation between clinical measurements and statistically significant differences in the fALFF/ALFF of various brain regions. Compared with healthy controls, both currently depressed and remitted patients showed increased fALFF/ALFF in the right putamen. Currently depressed MDD patients showed increased fALFF/ALFF in the right ventral median frontal gyrus relative to both the remitted MDD group and the healthy control group. The ALFF of the right precuneus was found to be positively correlated with the number of depressive episodes and the fALFF of the right precuneus to be positively correlated with the disease duration in currently depressed MDD patients. An abnormal fALFF/ALFF in the right ventral median frontal gyrus was found only in currently depressed patients, suggesting that such an anomaly may play a critical role in depressive symptomatology and may be a therapeutic target for MDD. An abnormal fALFF/ALFF in the right putamen is a potential candidate as a trait-related marker of vulnerability to major depression.