title: Neural substrates of shared attention as social memory: A hyperscanning functional magnetic resonance imaging study.
abstract: During a dyadic social interaction, two individuals can share visual attention through gaze, directed to each other (mutual gaze) or to a third person or an object (joint attention). Shared attention is fundamental to dyadic face-to-face interaction, but how attention is shared, retained, and neutrally represented in a pair-specific manner has not been well studied. Here, we conducted a two-day hyperscanning functional magnetic resonance imaging study in which pairs of participants performed a real-time mutual gaze task followed by a joint attention task on the first day, and mutual gaze tasks several days later. The joint attention task enhanced eye-blink synchronization, which is believed to be a behavioral index of shared attention. When the same participant pairs underwent mutual gaze without joint attention on the second day, enhanced eye-blink synchronization persisted, and this was positively correlated with inter-individual neural synchronization within the right inferior frontal gyrus. Neural synchronization was also positively correlated with enhanced eye-blink synchronization during the previous joint attention task session. Consistent with the Hebbian association hypothesis, the right inferior frontal gyrus had been activated both by initiating and responding to joint attention. These results indicate that shared attention is represented and retained by pair-specific neural synchronization that cannot be reduced to the individual level.
authors.affiliation: Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences (NIPS), Aichi 4448585, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Koike
authors.affiliation: Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences (NIPS), Aichi 4448585, Japan; Division of Psychology, Department of Social and Human Environment, Graduate School of Environmental Studies, Nagoya University, Nagoya 4648601, 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 (NIPS), Aichi 4448585, Japan.
authors.forename: Shuntaro
authors.initials: S
authors.lastname: Okazaki
authors.affiliation: Graduate School of Intercultural Studies, Kobe University, Kobe 6578501, Japan; Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences (NIPS), Aichi 4448585, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Nakagawa
authors.affiliation: Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences (NIPS), Aichi 4448585, Japan; Pathophysiological and Health Science Team, RIKEN Center for Life Science Technologies, Kobe 6500047, Japan; Department of Physiology, Osaka City University Graduate School of Medicine, Osaka 4678603, Japan.
authors.forename: Akihiro T
authors.initials: AT
authors.lastname: Sasaki
authors.affiliation: Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences (NIPS), Aichi 4448585, Japan; Research Center for Child Mental Development, University of Fukui, Fukui 9101193, Japan; Biomedical Imaging Research Center (BIRC), University of Fukui, Fukui 9101193, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Shimada
authors.affiliation: Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences (NIPS), Aichi 4448585, Japan.
authors.forename: Sho K
authors.initials: SK
authors.lastname: Sugawara
authors.affiliation: Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences (NIPS), Aichi 4448585, Japan; Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies), Kanagawa 2400193, Japan.
authors.forename: Haruka K
authors.initials: HK
authors.lastname: Takahashi
authors.affiliation: Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences (NIPS), Aichi 4448585, Japan; Department of Psychosomatic Medicine, Kyushu University, Fukuoka 8128582, Japan.
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Yoshihara
authors.affiliation: Institute for Neurobiology, National Autonomous University of Mexico, Santiago de Queretaro, Mexico; Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences (NIPS), Aichi 4448585, Japan.
authors.forename: Jorge
authors.initials: J
authors.lastname: Bosch-Bayard
authors.affiliation: Division of Cerebral Integration, Department of Cerebral Research, National Institute for Physiological Sciences (NIPS), Aichi 4448585, Japan; Department of Physiological Sciences, School of Life Sciences, SOKENDAI (The Graduate University for Advanced Studies), Kanagawa 2400193, Japan; Biomedical Imaging Research Center (BIRC), University of Fukui, Fukui 9101193, Japan. Electronic address: sadato@nips.ac.jp.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Sadato
mesh_terms: D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D007398:Interpersonal Relations; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory; D055815:Young Adult
keywords: Eye-blink synchronization; Hyperscanning; Inter-individual neural synchronization; Joint attention; Mutual gaze; Shared attention