Published papers

The Barcelona Music Reward Questionnaire (BMRQ) is an instrument designed to assess individual differences in music pleasure and reward. While the BMRQ was developed in Spanish and English, it has recently been translated into French and Chinese. A point of debate is whether the five-factor model, initially proposed in the English and Spanish versions of the BMRQ, was consistently replicated in the translated versions. While the French version successfully reproduced the five-factor model, the Chinese version did not, potentially due to cultural variations. In this study, we developed a Japanese version of the BMRQ (J-BMRQ) and tested whether the J-BMRQ could replicate the five-factor model. Data from 1550 Japanese participants were collected and analyzed using the J-BMRQ, and its construct validity and reliability were tested via factor analyses. Our analyses supported the applicability of the five-factor model for the Japanese version of the BMRQ, demonstrating psychometric properties consistent with the original Spanish/English and French versions. Additionally, mirroring the earlier versions, a single-factor solution was informative for computing an overall BMRQ score. This study reinforces the cross-cultural generalizability of the BMRQ and offers a robust tool for future research on musical pleasure and reward in a Japanese context.

Approximately 30% of patients with schizophrenia do not respond to antipsychotics. While schizophrenia has been primarily explained by the dopamine dysfunction hypothesis, treatment-resistant schizophrenia (TRS) may involve a different pathophysiology. Neuromelanin (NM), a product of dopamine metabolism in the substantia nigra (SN), indirectly measures long-term dopamine synthesis capacity. Few studies have examined SN NM levels in TRS. Therefore, we investigated the relationship between SN NM levels and treatment responsiveness in schizophrenia. We included age- and sex-matched TRS, patients with schizophrenia in remission of positive symptoms (SZ-R), and healthy controls (HCs). Neuromelanin-sensitive magnetic resonance imaging was used to measure SN NM signals. We also evaluated clinical symptoms and cognitive impairment. We conducted voxel-wise analyses of NM contrast-to-noise ratio (CNR) to compare groups pairwise. Correlation analyses examined relationships between NM signals and symptom severity. Seventy-two participants (n = 24 per group) completed the study. The TRS group had higher dorsal SN CNR than the HC group (510 out of 1948 voxels at p < 0.05, corrected p = 0.005, permutation test). In contrast, no significant differences were observed in the other comparisons. No significant correlations were found between NM CNR and clinical severity. Our findings contrast with previous positron emission tomography studies on dorsal striatal dopamine function. Since the dorsal SN contributes to both the mesolimbic and nigrostriatal pathways, with a relatively greater role in the former, dopamine functions in these pathways may play different roles for treatment responsiveness. Further research with multimodal imaging is needed to examine dopamine function and antipsychotic treatment responsiveness in schizophrenia.

Music chills are physical sensations, such as goosebumps, linked to intense pleasure and engage the brain’s reward system. However, individual differences in music preferences and neural responses make it difficult to enhance these experiences consistently. To address this issue, we developed the chill brain-music interface (C-BMI), a neurofeedback system that uses an in-ear electroencephalogram (EEG) to create personalized playlists. For each participant, we built two regression models: one predicting pleasure from acoustic features, and another decoding pleasure from EEG data. Using these models, four playlists were generated: two designed to enhance pleasure and two to reduce it. In each pair, one playlist incorporated real-time EEG-based updates, whereas the other relied solely on acoustic features. The EEG-updated pleasure-enhancing playlist elicited more subjective chills and higher pleasure ratings than the pleasure-reducing playlists, suggesting that adapting music selection to individual neural activities can amplify chills and emotional engagement with music.

Music chills are physical sensations, such as goosebumps, linked to intense pleasure and engage the brain's reward system. However, individual differences in music preferences and neural responses make it difficult to enhance these experiences consistently. To address this issue, we developed the chill brain-music interface (C-BMI), a neurofeedback system that uses an in-ear electroencephalogram (EEG) to create personalized playlists. For each participant, we built two regression models: one predicting pleasure from acoustic features, and another decoding pleasure from EEG data. Using these models, four playlists were generated: two designed to enhance pleasure and two to reduce it. In each pair, one playlist incorporated real-time EEG-based updates, whereas the other relied solely on acoustic features. The EEG-updated pleasure-enhancing playlist elicited more subjective chills and higher pleasure ratings than the pleasure-reducing playlists, suggesting that adapting music selection to individual neural activities can amplify chills and emotional engagement with music.

Controlling physiological and psychological states before a performance is essential for professional musicians to realize their full potential. However, the characteristics of the optimal pre-performance state remain unclear. While an increase in sympathetic nervous system activity is typically observed before performance, when associated with anxiety, it can degrade the performance quality. This study examined whether recalling positive autobiographical performance memories enhances subjective performance achievement, accompanied by increased emotional arousal, valence, and autonomic nervous system activity. Thirty-six professional wind instrument players participated in the study.Prior to performing musical pieces, participants engaged in one of three conditions: (1) recalling positive autobiographical memories, (2) recalling negative autobiographical memories, or (3) imagining routine pre-performance activities (no-memory condition). During the memory recall phase, heart rate was measured. After each performance, participants rated their subjective arousal, valence, and performance achievement. We calculated the heart rate variability indices, specifically SD1 (reflecting parasympathetic nervous system activity) and SD2/SD1 (used as a relative indicator of sympathetic predominance). The results showed that performance achievement, arousal, and valence were significantly higher in the positive than in the negative condition. Our path analysis further revealed that an increase in SD2/SD1 did not directly predict performance achievement; instead, it was associated with an increase in emotional valence, which in turn led to improved performance. These findings suggest that recalling positive performance memories activates sympathetic nervous system activity and fosters positive emotions, thereby enhancing the performance achievement of professional musicians.

Professional hand percussionists who play the darbuka (a drum from the Middle East) show fast and stable bimanual finger coordination compared to amateur players. A cross-recurrence quantification analysis clarifies how stable bimanual coordination is achieved by dissociating stochastic noise and attractor strength in the dynamic system. This study employed a cross-recurrence quantification analysis to examine professional and amateur darbuka players’ fast and stable bimanual finger coordination. Eight professional and eight amateur percussion players participated in the study and played a darbuka with their right and left ring fingers, alternating as fast as possible for 12 s. We then analyzed the finger position data and calculated the stochastic noise and attractor strength from the density and the longest diagonal line in the recurrence plot, respectively. We used linear mixed-effects models to test whether stochastic noise and attractor strength differed between professional and amateur players. The results indicate that professional darbuka players achieve fast and stable bimanual finger coordination by enhancing attractor strength rather than reducing stochastic noise in the dynamic system.

Music is present in every known society but varies from place to place. What, if anything, is universal to music cognition? We measured a signature of mental representations of rhythm in 39 participant groups in 15 countries, spanning urban societies and Indigenous populations. Listeners reproduced random ‘seed’ rhythms; their reproductions were fed back as the stimulus (as in the game of ‘telephone’), such that their biases (the prior) could be estimated from the distribution of reproductions. Every tested group showed a sparse prior with peaks at integer-ratio rhythms. However, the importance of different integer ratios varied across groups, often reflecting local musical practices. Our results suggest a common feature of music cognition: discrete rhythm ‘categories’ at small-integer ratios. These discrete representations plausibly stabilize musical systems in the face of cultural transmission but interact with culture-specific traditions to yield the diversity that is evident when mental representations are probed across many cultures.

In opera singing competitions, judges use an overall score to evaluate the singers' voices and determine their rankings. This score not only guides the singers' technique and expressiveness but also serves as a crucial indicator that can significantly influence their careers. However, the specific elements captured by this overall score remain unclear. To address this gap, the present study analyzed opera singing recordings to identify the factors that explain the overall score. Ten trained female Japanese singers performed “Caro mio ben” under standardized recording conditions. Four experts evaluated the recorded performances by assigning an overall score of 100 points and rating six vocal attributes: vibrato, resonance, timbre, diction, intonation, and expressiveness. The recordings were then analyzed to calculate specific acoustic and audio features, including the singing power ratio (SPR), harmonic-to-noise ratio (HNR), and loudness units full scale (LUFS). We developed two linear mixed models: the first regressed the overall score on the subjective vocal attributes, whereas the second predicted the overall score from the acoustic features. Evaluator identity was included as a random effect in both models. The results showed that vibrato was a significant predictor of the overall score in the first model. In the second model, only SPR emerged as a significant predictor. These findings suggest that vibrato, which reflects emotional expressiveness and vocal control, and SPR, which indicates the relative power in the high-frequency band (2–4 kHz) and assists a voice clearer than the accompaniment, are key factors in explaining the overall score in opera singing.

Background music (BGM), typically played at low volumes in everyday environments, has been shown to influence mood and behavior. However, its effects on listeners’ moods in clinical settings remain underexplored. This study aimed to examine whether a BGM intervention would enhance the mood of older individuals in a senior daycare facility in Japan. Additionally, we investigated whether BGM would improve the mood and work performance of staff members. Fifty older individuals and twenty staff members participated in this study. Following a one-week baseline period without BGM, four BGM playlists were administered, each played for one week, with a one-week interval between playlists. Mood and work performance were assessed using questionnaires developed for this study. Our findings showed no significant changes in the mood of older participants during the BGM interventions compared to baseline. However, the mood of the staff members significantly improved from baseline in both the morning and afternoon. By contrast, no significant effects on staff members’ work performance were observed. Although we did not observe the positive effects of BGM on the mood of older listeners, the results suggest that BGM may enhance the mood of staff members in clinical settings.