The Role of Temperament Traits in Bipolar Disorder: Neuroimaging Study

Abstract

Purpose: This study aimed to identify temperament traits alterations in bipolar disorder (BD) and explore their potential neuroimaging correlates using resting-state functional magnetic resonance imaging. Methods: We assessed seed-to-voxel alterations in four large-scale brain networks (Salience, Frontoparietal, Default Mode, and SensoriMotor) in 49 patients with BD and 49 healthy individuals according to the difference of temperamental traits (Reward Dependence, Novelty Seeking, Harm Avoidance, and Persistence). Also, we measured the relationship of temperamental traits with the severity of manic and depressive symptoms and impulsivity. Results: Lower Reward Dependence (t-Welch's (87.1) = -2.50; p=0.014) in bipolar patients was associated with increased functional connectivity between Salience Network and Default Mode and FrontoParietal Networks. Higher Novelty Seeking (t-Welch's (87.3) = 4.37; p < 0.001) was associated with increased functional connectivity within FrontoParietal Network, whereas its functional connectivity with Visual and Dorsal Attention Networks was decreased. Higher Harm Avoidance (t-Welch's (82.8) = 4.85; p < 0.001) was associated with increased functional connectivity between FrontoParietal Network and basal ganglia. Lower Persistence (U = 998; p=0.002) was associated with decreased functional connectivity within FrontoParietal Network and with Default Mode Network. Higher persistence in bipolar patients was associated with greater severity of manic symptoms (Spearman's rho = 0.302, p=0.018), while lower Reward Dependence was associated with increased severity of depressive symptoms (Pearson's r = -0.388, p=0.003). Harm Avoidance negatively correlates with Persistence (Pearson's r = -0.525, p < 0.001) and positively with reward dependence (Pearson's r = -0.259, p=0.036). We also found a negative correlation between impulsivity and Reward Dependence (Pearson's r = -0.312, p=0.029) and positive correlation between impulsivity and Novelty Seeking (Pearson's r = 0.525, p < 0.001). Conclusions: The findings demonstrate a possible functional neuroimaging basis for altered temperamental traits in patients with bipolar disorder.

Keywords: bipolar disorder; functional connectivity; impulsivity; neuroimaging; temperament.

Figure 1

Correlation matrices of affective symptom severity, impulsivity and temperament traits. Abbreviations: HAMD21, Hamilton Depression Rating Scale (21 items); p, level of statistical significance; r, Pearson's correlation coefficient; rho, Spearman's correlation coefficient; YMRS, Young Mania Rating Scale.

Figure 2

Functional connectivity alteration due to lower Reward Dependence in BD patients compared to the HC. (A) Violin plots showing the difference in the severity of the Reward Dependence (t-Welch's = 0.486; p=0.014); (B) Seed-based connectivity map for the anterior cingulate cortex seed (SN), demonstrating the altered functional connectivity in BD compared to HC based on the severity of the Reward Dependence; (C) Polar display showing the number of altered voxels (shown in B) in each large-scale brain network.

Figure 3

Functional connectivity alteration due to higher Novelty Seeking in BD patients compared to the HC. (A) Violin plots showing the difference in the severity of the temperament trait “Novelty Seeking” (t-Welch's = 0.848; p < 0.001); (B) Seed-based connectivity map for the anterior cingulate cortex and anterior insula seeds (SN), demonstrating the difference in their functional connectivity in BD compared to HC based on the severity of the temperament trait “Novelty Seeking”; (C) Polar display showing the number of altered voxels (shown in B) in each network.

Figure 4

Functional connectivity alterations due to the higher Harm Avoidance level in BD patients compared to the HC. (A) Violin plots showing the difference in the severity of the Harm Avoidance (t-Welch's = 0.945; p < 0.001); (B) Seed-based connectivity map for the posterior parietal cortex seed (FPN), demonstrating the difference in its functional connectivity in BD compared to HC based on the severity of the higher Harm Avoidance.

Figure 5

Functional connectivity alterations due to the severity of the Persistence in BD patients compared to the HC. (A) Violin plots showing the difference in the severity of the Persistence (t-Welch's = 0.848; p < 0.001); (B) Seed-based connectivity map for the anterior cingulate cortex and anterior insula seeds (SN), demonstrating the difference in their functional connectivity in BD compared to HC based on the severity of the Persistence; (C) Polar display showing the number of altered voxels (shown in B) in each network.