Negative mood state enhances the susceptibility to unpleasant events: neural correlates from a music-primed emotion classification task

Abstract

Background: Various affective disorders are linked with enhanced processing of unpleasant stimuli. However, this link is likely a result of the dominant negative mood derived from the disorder, rather than a result of the disorder itself. Additionally, little is currently known about the influence of mood on the susceptibility to emotional events in healthy populations.

Method: Event-Related Potentials (ERP) were recorded for pleasant, neutral and unpleasant pictures while subjects performed an emotional/neutral picture classification task during positive, neutral, or negative mood induced by instrumental Chinese music.

Results: Late Positive Potential (LPP) amplitudes were positively related to the affective arousal of pictures. The emotional responding to unpleasant pictures, indicated by the unpleasant-neutral differences in LPPs, was enhanced during negative compared to neutral and positive moods in the entire LPP time window (600-1000 ms). The magnitude of this enhancement was larger with increasing self-reported negative mood. In contrast, this responding was reduced during positive compared to neutral mood in the 800-1000 ms interval. Additionally, LPP reactions to pleasant stimuli were similar across positive, neutral and negative moods except those in the 800-900 ms interval.

Implications: Negative mood intensifies the humans' susceptibility to unpleasant events in healthy individuals. In contrast, music-induced happy mood is effective in reducing the susceptibility to these events. Practical implications of these findings were discussed.

Figure 1. The results of the mood valence and arousal ratings for the pre-experiment phase, and for neutral, positive and negative mood induction phases.

Error bars represent the standard deviation (SD).

Figure 2

Left: Averaged ERPs at Fz, FCz, Cz, CPz and Pz for unpleasant (solid lines) and neutral (dashed lines) pictures during positive (happy, black lines), negative (sad, red lines) and neutral (blue lines) mood states. Right: Averaged ERPs for pleasant (solid lines) and neutral (dashed lines) pictures during positive (black lines), negative (red lines) and neutral (blue lines) mood states.

Figure 3

Left: the unpleasant picture-neutral picture difference waves in the positive (black lines), negative (red lines) and neutral (blue lines) mood states at Fz, FCz, Cz, CPz and Pz. Right: the pleasant picture-neutral picture difference waves in the positive, negative and neutral mood states at these sites.

Figure 4

Left: topographical maps of voltage amplitudes for unpleasant picture-neutral picture difference ERPs in the negative, neutral and positive mood blocks in the 600–700 ms, 700–800 ms and 800–900 ms intervals. Right: topographical maps of pleasant picture-neutral picture difference ERPs in the negative, neutral and positive mood blocks in these intervals.

Figure 5. Schematic illustration of the emotion effect for unpleasant (unpleasant-neutral difference amplitudes, Top panel) and pleasant (pleasant-neutral difference amplitudes, Bottom panel) pictures during neutral, positive and negative mood states in every 100 ms of the 600–1000 ms time window.

Error bars represent ±standard errors.

Figure 6. The Scatterplot for the correlation between the pictures' arousal and the amplitudes of each ERP component in the present study.

LPP, instead of other components, served as a predictor for the pictures' arousal level.

Figure 7. The scatterplot for the correlation between the enhancement of the LPP emotion effect for unpleasant pictures and the arousal of negative mood during sad music.

The former was computed by subtracting the unpleasant effect (unpleasant-neutral pictures in the 600–1000 ms) in the neutral block from that in the sad block. The latter was computed by subtracting pre-experiment mood arousal from the mood arousal in the sad block.