title: How Two Brains Make One Synchronized Mind in the Inferior Frontal Cortex: fNIRS-Based Hyperscanning During Cooperative Singing.
abstract: One form of communication that is common in all cultures is people singing together. Singing together reflects an index of cognitive synchronization and cooperation of human brains. Little is known about the neural synchronization mechanism, however. Here, we examined how two brains make one synchronized behavior using cooperated singing/humming between two people and hyperscanning, a new brain scanning technique. Hyperscanning allowed us to observe dynamic cooperation between interacting participants. We used functional near-infrared spectroscopy (fNIRS) to simultaneously record the brain activity of two people while they cooperatively sang or hummed a song in face-to-face (FtF) or face-to-wall (FtW) conditions. By calculating the inter-brain wavelet transform coherence between two interacting brains, we found a significant increase in the neural synchronization of the left inferior frontal cortex (IFC) for cooperative singing or humming regardless of FtF or FtW compared with singing or humming alone. On the other hand, the right IFC showed an increase in neural synchronization for humming only, possibly due to more dependence on musical processing.
authors.affiliation: Department of Psychology, Graduate School of Letters, Kyoto University Kyoto, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Osaka
authors.affiliation: Department of Psychology, Graduate School of Human Sciences, Osaka University Suita, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Minamoto
authors.affiliation: Department of Psychology, Graduate School of Letters, Kyoto University Kyoto, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Yaoi
authors.affiliation: Department of Psychology, Graduate School of Human Sciences, Osaka University Suita, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Azuma
authors.affiliation: Center for Baby Science, Doshisha University Kyoto, Japan.
authors.forename: Yohko Minamoto
authors.initials: YM
authors.lastname: Shimada
authors.affiliation: Department of Psychology, Graduate School of Human Sciences, Osaka University Suita, Japan ; Center for Information and Neural Networks, Osaka University Suita, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Osaka
keywords: cooperation; fNIRS; humming; hyperscanning; inferior frontal cortex; singing