Background Music Dependent Reduction of Aversive Perception and Its Relation to P3 Amplitude Reduction and Increased Heart Rate

Figure 1. Schematic representation of the study. The study was conducted following randomized counterbalanced crossover design. Each participant underwent three experiments with different background music conditions. In each background music condition, two blocks of experiments were conducted. In block 1, participants were exposed to selected background music for 5 min. In block 2, participants were exposed to the background music for 5 min, followed by exposure to the same background music with intermittent sound stimuli.

Figure 2. Affective responses and consequential mood for each background music condition. (A) Affective responses to relaxing background music (RelaxBGM) and busy background music (BusyBGM) are shown based on two-dimensional evaluation: valence and arousal. Note that RelaxBGM was more pleasant and calming than BusyBGM. (B) Emotional consequences of listening to each background music for 5 min are shown. Note that mood worsened in BusyBGM and no background music (NoBGM) conditions, whereas RelaxBGM prevented the worsening. (C) Heart rate (HR) changes were noted during exposure to each background music. HR increased in BusyBGM, while HRs at the beginning were similar in all conditions. Asterisk shows significant difference between the indicated pair.

Figure 3. Affective response to white noise and pure tone for each background music condition. Self-Assessment Manikin (SAM) scores for white noise and pure tone are graphically presented. Panel (A) shows the valence scores, whereas Panel (B) shows the arousal scores. Significant difference due to background music condition is shown by asterisk.

Figure 4. Event-related potentials (ERPs) to white noise and pure tone for each background music condition. Each panel shows the grand average ERP for each BGM condition. ERPs evoked by white noise (blue line), and pure tone (green line) are presented. Shaded colors represent the mean ± standard error. (The inset box) The electrodes used in the calculation of ERP (Pz, Cz, C3, and C4) are shown in red, while others are in blue.

Figure 5. Source localization of differences in ERPs. Differences in neuroelectric activity induced by white noise and pure tone are presented. Regions with significantly increased neuroelectric activity responding to white noise stimulus are shown in yellow to red gradations. (A) Increased activities were found around Brodmann area 40 in no background music (NoBGM) condition. (B) Increased activities were found around Brodmann area 31 in relaxing background music (RelaxBGM) condition. (C) No statistically different responses were found in busy background music (BusyBGM) condition. Color bars show the locations of extreme t-values that close to the significant level (P < 0.05, corrected for multiple comparisons). Maximum t-value and corresponding P-value are described above in corresponding figures, and the regions of maximum difference are shown as Montreal Neurological Institute (MNI) coordinates.