Altered Brain Function in Treatment-Resistant and Non-treatment-resistant Depression Patients: A Resting-State Functional Magnetic Resonance Imaging Study

Abstract

Objective: In this study, we used amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) to observe differences in local brain functional activity and its characteristics in patients with treatment-resistant depression (TRD) and non-treatment-resistant depression (nTRD), and to explore the correlation between areas of abnormal brain functional activity and clinical symptoms.

Method: Thirty-seven patients with TRD, 36 patients with nTRD, and 35 healthy controls (HCs) were included in resting-state fMRI scans. ALFF and ReHo were used for image analysis and further correlation between abnormal brain regions and clinical symptoms were analyzed.

Results: ANOVA revealed that the significantly different brain regions of ALFF and ReHo among the three groups were mainly concentrated in the frontal and temporal lobes. Compared with the nTRD group, the TRD group had decreased ALFF in the left/right inferior frontal triangular gyrus, left middle temporal gyrus, left cuneus and bilateral posterior lobes of the cerebellum, and increased ALFF in the left middle frontal gyrus and right superior temporal gyrus, and the TRD group had decreased ReHo in the left/right inferior frontal triangular gyrus, left middle temporal gyrus, and increased ReHo in the right superior frontal gyrus. Compared with the HC group, the TRD group had decreased ALFF/ReHo in both the right inferior frontal triangular gyrus and the left middle temporal gyrus. Pearson correlation analysis showed that both ALFF and ReHo values in these abnormal brain regions were positively correlated with HAMD-17 scores (P < 0.05).

Conclusion: Although the clinical symptoms were similar in the TRD and nTRD groups, abnormal neurological functional activity were present in some of the same brain regions. Compared with the nTRD group, ALFF and ReHo showed a wider range of brain area alterations and more complex neuropathological mechanisms in the TRD group, especially in the inferior frontal triangular gyrus of the frontal lobe and the middle temporal gyrus of the temporal lobe.

Keywords: amplitude of low-frequency fluctuation; fMRI; non-treatment-resistant depression; regional homogeneity; treatment-resistant depression.

Figure 1

Based on one-way ANOVA for three groups of ALFF abnormal brain regions. The color bars indicate the F-value.

Figure 2

Based on one-way ANOVA for three groups of ReHo abnormal brain regions. The color bars indicate the F-value.

Figure 3

Brain regions with abnormal ALFF (left) and ReHo (right) between TRD group and nTRD group based on post hoc T-tests. The color bars indicate the T-value.

Figure 4

Brain regions with abnormal ALFF (left) and ReHo (right) between TRD group and HC group based on post hoc T-tests. The color bars indicate the T-value.

Figure 5

Brain regions with abnormal ALFF (left) and ReHo (right) between nTRD group and HC group based on post hoc T-tests. The color bars indicate the T-value.

Figure 6

Positive correlation between the ALFF and ReHo of the abnormal brain regions: ①Frontal_Inf_Tri_L, Left inferior frontal triangular gyrus; ALFF value of TRD group; ②Temporal_Mid_L, left middle temporal gyrus; ALFF value of TRD group; ③Cerebelum_Crus1, bilateral posterior lobes of the cerebellum(Crus I); ALFF value of TRD group; ④Temporal_Mid_L, left middle temporal gyrus; ReHo value of TRD group; ⑤Frontal_Inf_Tri_L, Left inferior frontal triangular gyrus; ALFF value of nTRD group; ⑥Frontal_Inf_Tri_R, Right inferior frontal triangular gyrus; ALFF value of nTRD group; ⑦Frontal_Inf_Tri_R, Right inferior frontal triangular gyrus; ReHo value of nTRD group.