title: Synchronous brain activity across individuals underlies shared psychological perspectives.
abstract: For successful communication, we need to understand the external world consistently with others. This task requires sufficiently similar cognitive schemas or psychological perspectives that act as filters to guide the selection, interpretation and storage of sensory information, perceptual objects and events. Here we show that when individuals adopt a similar psychological perspective during natural viewing, their brain activity becomes synchronized in specific brain regions. We measured brain activity with functional magnetic resonance imaging (fMRI) from 33 healthy participants who viewed a 10-min movie twice, assuming once a 'social' (detective) and once a 'non-social' (interior decorator) perspective to the movie events. Pearson's correlation coefficient was used to derive multisubject voxelwise similarity measures (inter-subject correlations; ISCs) of functional MRI data. We used k-nearest-neighbor and support vector machine classifiers as well as a Mantel test on the ISC matrices to reveal brain areas wherein ISC predicted the participants' current perspective. ISC was stronger in several brain regions--most robustly in the parahippocampal gyrus, posterior parietal cortex and lateral occipital cortex--when the participants viewed the movie with similar rather than different perspectives. Synchronization was not explained by differences in visual sampling of the movies, as estimated by eye gaze. We propose that synchronous brain activity across individuals adopting similar psychological perspectives could be an important neural mechanism supporting shared understanding of the environment.
authors.affiliation: Brain and Mind Laboratory, Department of Biomedical Engineering and Computational Science (BECS), School of Science, Aalto University, FI-00076 Espoo, Finland; Advanced Magnetic Imaging Centre, Aalto NeuroImaging, School of Science, Aalto University, FI-00076 Espoo, Finland. Electronic address: juha.lahnakoski@aalto.fi.
authors.forename: Juha M
authors.initials: JM
authors.lastname: Lahnakoski
authors.affiliation: Brain and Mind Laboratory, Department of Biomedical Engineering and Computational Science (BECS), School of Science, Aalto University, FI-00076 Espoo, Finland.
authors.forename: Enrico
authors.initials: E
authors.lastname: Glerean
authors.affiliation: Brain and Mind Laboratory, Department of Biomedical Engineering and Computational Science (BECS), School of Science, Aalto University, FI-00076 Espoo, Finland.
authors.forename: Iiro P
authors.initials: IP
authors.lastname: Jääskeläinen
authors.affiliation: Department of Psychology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Hyönä
authors.affiliation: Brain Research Unit, O.V. Lounasmaa Laboratory, School of Science, Aalto University, FI-00076 Espoo, Finland.
authors.forename: Riitta
authors.initials: R
authors.lastname: Hari
authors.affiliation: Brain and Mind Laboratory, Department of Biomedical Engineering and Computational Science (BECS), School of Science, Aalto University, FI-00076 Espoo, Finland.
authors.forename: Mikko
authors.initials: M
authors.lastname: Sams
authors.affiliation: Brain and Mind Laboratory, Department of Biomedical Engineering and Computational Science (BECS), School of Science, Aalto University, FI-00076 Espoo, Finland; Brain Research Unit, O.V. Lounasmaa Laboratory, School of Science, Aalto University, FI-00076 Espoo, Finland; Turku PET Centre, University of Turku, FI-20521 Turku, Finland.
authors.forename: Lauri
authors.initials: L
authors.lastname: Nummenmaa
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D059907:Functional Neuroimaging / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D056345:Theory of Mind / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
keywords: Attention; Inter-subject correlation; Psychological perspective; fMRI