Eleventh International School on Mind, Brain and Education

2016 September 7–13

Dynamical Coupling:
From Brain-to-Brain to Social Interaction

Directors of the School: Antonio M. Battro and Kurt W. Fischer
Directors of the Course: Uri Hasson and Thalia Wheatley

Abstract: Norihiro Sadato
National Institute for Physiological Sciences (NIPS), Japan

Shared attention and inter-individual neural synchronization in the human right inferior frontal gyrus
Face-to-face interactants can share attention through eye-contact and joint attention that are tightly coupled. Hyper-scanning fMRI in pairs of adults conducting joint attention showed the inter-individual neural synchronization in the right inferior frontal gyrus after all the task-related effects were modeled out. To explore how the joint attention and eye-contact generates the state of shared attention, we conducted hyper-scanning fMRI in which pairs of participants performed a real-time mutual gaze before and after the joint attention. During mutual gaze, eye-blink synchronization, a behavioral index of shared attention, increased after the joint attention. Increment of eye-blink synchronization was positively correlated with the increment of the inter-individual neural synchronization within the right inferior frontal gyrus during mutual gaze. This enhanced neural synchronization was also positively correlated with enhanced eye-blink synchronization during the previous joint attention. Thus shared attention is represented and retained by pair-specific neural synchronization of the right inferior frontal gyrus that cannot be reduced to the individual level. This inter-brain effect highlights the role of the right inferior frontal gyrus in the execution and learning of attentional coordination and sharing attention between self and others.

After trained as a diagnostic radiologist, I entered into the functional imaging field in 1990. Initially I have worked on positron emission tomography (PET) then gradually shifted to the functional MRI over several years. I am interested in understanding of the mechanisms of plastic change in the human brain accompanied by learning, sensory deprivation, and development. One of the remarkable findings I obtained by a multimodal approach with PET, fMRI, and TMS was the plastic change of the primary visual cortex of the blind during Braille reading (Sadato et al, 1996; Cohen et al. 1997; Sadato et al. 2002). Recently I focus on the development of the social cognition and its neural correlates. Technically, hyper-scanning fMRI (with two MRI scanners) is applied to explore the neural substrates of the inter-subject interaction during joint attention and eye-contact (Saito et al. 2010; Tanabe et al. 2012; Koike et al. 2016).