Biology subjects

Etani, T.

Publications and source records attributed to Etani, T..

6 recordsLinked to original sources

bioRxiv2026

Postmortem Alterations of Metabotropic Glutamate Receptors across Neuropsychiatric Disorders: A Systematic Review

Metabotropic glutamate receptors (mGluRs) regulate glutamatergic transmission and have been implicated in diverse neuropsychiatric disorders, but human postmortem evidence remains fragmented. We aimed to map these findings across diagnoses, receptor subtypes, brain regions, and measurement modalities. Following PRISMA guidelines, we systematically searched MEDLINE, EMBASE, and Web of Science from inception to August 8, 2026, for studies assessing GRM transcripts, as well as mGluR protein abundance, localization, assembly, or receptor binding in human postmortem brain tissue. Of 532 records identified, 57 reports met eligibility criteria. Findings were synthesized narratively because of substantial heterogeneity in diagnoses, brain regions, receptor subtypes, and assays. Postmortem evidence was concentrated on mGluR5, mGluR2/3, and mGluR1, and on the prefrontal cortex, anterior cingulate cortex, and hippocampus. mGluR-related alterations were reported across disorders, including schizophrenia, major depressive disorder, Alzheimer disease, autism spectrum disorder, and alcohol use disorder. Although most analyses yielded null findings, the direction and magnitude of mGluR alterations varied across brain regions, receptor subtypes, and molecular endpoints. This inconsistency may partly reflect the distinct biological levels captured by transcript abundance, total protein, receptor assembly, localization, and ligand binding, together with regional, cell-type, disease-stage, and clinical heterogeneity. The available evidence therefore suggests context-dependent alterations in mGluR biology but not a uniform or disorder-specific molecular signature. Integration of postmortem findings with other approaches, including in vivo imaging, may clarify their biological and clinical significance.

neuroscience↗

bioRxiv2026

Modulating supplementary motor area excitability enhances groove-related pleasure during music listening

Pleasurable urge to move to music is often referred to as groove. Although previous studies have shown an association between the supplementary motor area (SMA) and the groove experience, its causal role remains unclear. Here, we investigated whether the SMA is causally involved in groove experience during music listening using repetitive transcranial magnetic stimulation. Fifteen healthy participants completed three sessions on separate days: excitatory stimulation (intermittent theta burst stimulation; iTBS) over the SMA, inhibitory stimulation (continuous theta burst stimulation; cTBS) over the SMA, and sham stimulation (iTBS or cTBS) over the vertex. After each stimulation session, participants listened to five high-groove and five low-groove musical excerpts and rated urge-to-move and pleasure on a 0-100 scale. Heart rate was additionally recorded as an exploratory physiological measure during music listening. Linear mixed-effects models (LMM) showed that pleasure ratings, but not urge-to-move ratings, were higher following both iTBS and cTBS compared with sham stimulation. In exploratory LMMs, reduced log-transformed heart rate variability (HRV) significantly predicted higher pleasure ratings. These findings suggest that SMA stimulation modulates the pleasurable component of the groove experience, likely via network-level mechanisms rather than a simple linear relationship between SMA excitability and pleasure. They also raise the possibility that reduced parasympathetic activity, reflected by lower HRV, mediates the stimulation-related increase in musical pleasure. Future studies should investigate the causal roles of other brain regions as well as clarify the directionality between autonomic changes and the groove experience.

neuroscience↗

bioRxiv2025

A groove brain-music interface for enhancing individual experience of urge to move

When we listen to music, we often feel a pleasurable urge to move to music, known as groove. While previous studies have identified musical features that contribute to the groove experience, such as syncopation and tempo, they also report individual differences in which kinds of music people experience groove. Therefore, recommending groove-eliciting music requires accounting for individual differences. In this study, we aimed to develop a groove brain-music interface (G-BMI) that generates personalized playlists to maximize each individuals groove experience, using a neurofeedback system based on in-ear EEG. Twenty-four participants listened to three high-groove and three low-groove musical excerpts and rated their "urge to move." Using these ratings and the recorded EEG, we trained two LASSO models to build the G-BMI. Model 1 predicted urge to move from acoustic features extracted with VGGish, a pretrained neural network. Model 2 classified EEG data as recorded during listening to high-groove or low-groove music. Using Model 1, we ranked 7,225 candidate songs by predicted groove and assembled one groove-augmenting and one groove-diminishing playlist. Using Models 1 and 2, we created two additional playlists that updated Model 1 and the ranking in real-time based on in-ear EEG. Participants then listened to all four playlists and rated them on items including "urge to move." The groove-augmenting playlist that incorporated EEG achieved the highest "urge to move" ratings. These findings suggest that a personalized neurofeedback system employing EEG can help maximize individual groove experience.

neuroscience↗

bioRxiv2025

Pleasure in groove is associated with neuromelanin levels in the substantia nigra of younger healthy individuals: A neuromelanin-sensitive MRI study

The pleasurable urge to move in response to music is called groove. Prior research has suggested a potential link between groove and dopamine function. However, no studies to date have directly investigated the relationship between the two. Here, we aimed to assess individual dopamine function in the substantia nigra of healthy individuals using neuromelanin-sensitive magnetic resonance imaging (NM-MRI), a non-invasive method associated with dopamine function, and to investigate the relationship between the individual dopamine proxy index and sensitivity to the groove experience. In this study, 15 younger (< 48 years) and 16 older ([greater double equals]48 years) healthy individuals participated. Participants listened to ten musical excerpts and rated the groove experience based on "pleasure" and "wanting to move." To assess whether the groove experience is related to NM levels, type of musical excerpts, and sex, we analyzed with linear mixed-effects regression models. The results showed that higher NM levels (p = 0.032) and male sex (p = 0.034) were associated with higher pleasure ratings in the younger group. For the "urge to move" ratings, type of musical excerpts was associated with ratings in both groups (ps < 0.001), where high-groove music (Janata et al., 2012) receiving higher ratings. Taken together, these results suggest that the "pleasure" aspect of the groove experience in younger individuals was related to dopamine levels in the substantia nigra, but may not be associated with the "urge to move." Thus, pleasure and the urge to move are likely to involve distinct dopaminergic pathways and mechanisms, warranting further investigation.

neuroscience↗

bioRxiv2024

A chill brain-music interface for enhancing music chills with personalized playlists

Music chills are pleasurable experiences while listening to music, often accompanied by physical responses, such as goosebumps1,2. Enjoying music that induces chills is central to music appreciation, and engages the reward system in the brain3-5. However, the specific songs that trigger chills vary with individual preferences6, and the neural substrates associated with musical rewards differ among individuals7-9, making it challenging to establish a standard method for enhancing music chills. In this study, we developed the Chill Brain-Music Interface (C-BMI), a closed-loop neurofeedback system that uses in-ear electroencephalogram (EEG) for song selection. The C-BMI generates personalized playlists aimed at evoking chills by integrating individual song preferences and neural activity related to music reward processing. Twenty-four participants listened to both self-selected and other-selected songs, reporting higher pleasure levels and experiencing more chills in their self-selected songs. We constructed two LASSO regression models to support the C-BMI. Model 1 predicted pleasure based on the acoustic features of the self-selected songs. Model 2 classified the EEG responses when participants listened to self-selected versus other-selected songs. Model 1 was applied to over 7,000 candidate songs, predicting pleasure scores. We used these predicted scores and acoustic similarity to the self-selected songs to rank songs that were likely to induce pleasure. Using this ranking, four tailored playlists were generated. Two playlists were designed to augment pleasure by selecting top-ranked songs, one of which incorporated real-time pleasure estimates from Model 2 to continuously update Model 1 and refine song rankings. Additionally, two playlists aimed to diminish pleasure, with one updated using Model 2. We found that the pleasure-augmenting playlist with EEG-based updates elicited more chills and higher pleasure levels than pleasure-diminishing playlists. Our results indicate that C-BMI using in-ear EEG data can enhance music-induced chills.

neuroscience↗

bioRxiv2024

A Nostalgia Brain-Music Interface for Enhancing Nostalgia, Well-Being, and Memory Vividness in Young and Elderly Individuals

Music-evoked nostalgia has the potential to assist in recalling autobiographical memories and enhancing well-being. However, nostalgic music preferences vary from person to person, presenting challenges for applying nostalgia-based music interventions in clinical settings, such as a non-pharmacological approach. To address these individual differences, we developed the Nostalgia Brain-Music Interface (N-BMI), a neurofeedback system that recommends nostalgic songs tailored to each individual. This system is based on prediction models of nostalgic feelings, developed by integrating subjective nostalgia ratings, acoustic features and in-ear electroencephalographic (EEG) data during song listening. To test the effects of N-BMI on nostalgic feelings, well-being, and memory recall, seventeen elderly and seventeen young participants took part in the study. The N-BMI was personalized for each individual, and songs were recommended under two conditions: the "nostalgia condition", where songs were selected to enhance nostalgic feelings, and the "control condition", to reduce nostalgic feelings. We found nostalgic feelings, well-being, and memory vividness were significantly higher after listening to the recommended songs in the nostalgia condition compared to the control condition in both groups. This indicates that the N-BMI enhanced nostalgic feelings, well-being, and memory recall across both groups. The N-BMI paves the way for innovative therapeutic interventions, including non-pharmacological approaches.

neuroscience↗