title: Hyperscanning neuroimaging technique to reveal the "two-in-one" system in social interactions.
abstract: Using a technique for measuring brain activity simultaneously from two people, known as hyperscanning, we can calculate inter-brain neural effects that appear only in interactions between individuals. Hyperscanning studies using fMRI are advantageous in that they can precisely determine the region(s) involved in inter-brain effects. However, it is almost impossible to record inter-brain effects in daily life. By contrast, hyperscanning EEG studies have high temporal resolution and could be used to capture moment-to-moment interactions. In addition, EEG instrumentation is portable and easy to wear, offering the opportunity to record inter-brain effects during daily-life interactions. However, the disadvantage of this approach is that it is difficult to localize the epicenter of the inter-brain effect. fNIRS has better temporal resolution and portability than fMRI, but has limited spatial resolution and a limited ability to record deep brain structures. Future studies should employ hyperscanning EEG-fMRI, because this approach combines the high temporal resolution of EEG with the high spatial resolution of fMRI. Hyperscanning EEG-fMRI allows us to use inter-brain effects as neuromarkers of the properties of social interactions in daily life. We also wish to emphasize the need to develop a mathematical model explaining how two brains can exhibit synchronized activity.
authors.affiliation: Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences, Aichi, Japan. Electronic address: tkoike@nips.ac.jp.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Koike
authors.affiliation: Division of Psychology, Department of Social and Human Environment, Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan; Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences, Aichi, Japan.
authors.forename: Hiroki C
authors.initials: HC
authors.lastname: Tanabe
authors.affiliation: Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences, Aichi, Japan.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Sadato
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods; D004569:Electroencephalography / Q000379:methods; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008959:Models, Neurological; D059906:Neuroimaging / Q000295:instrumentation / Q000379:methods
keywords: Hyperscanning; Social interaction; Social neuroscience