Reduced inter-subject functional connectivity during movies in autism: Replicability across cross-national fMRI datasets

Autism is a neurodevelopmental condition characterized by impairedsocial communication and interaction, restricted interests, stereotypedbehaviors, and altered sensory responses to external stimuli (AmericanPsychiatric Association, 2013). Many autistic individuals withoutintellectual impairment perform well in controlled tasks, such asrecognizing emotional facial expressions (Keating et al., 2023), but theirperformance often declines in naturalistic settings requiring implicit socialprocessing (Van de Cruys et al., 2014). Functional magnetic resonanceimaging (fMRI), during naturalistic stimuli, such as movies, has proveneffective for examining social brain activity (Finn et al., 2020). Intersubjectfunctional connectivity (ISFC) measures the interregionalconnectivity across individuals, by separating the shared and stimulusdrivencomponent of fMRI responses from intrinsic brain activity andnoise (Simony et al., 2016). Previous findings suggest idiosyncratic ISFCpatterns in autistic individuals (Bolton et al., 2018), but the preciseregional differences remain unclear and may vary across movie segments.Addressing the reproducibility crisis in neuroimaging (Kelly & Hoptman,2022), cross-center experiment design can validate the generalizability offindings. This study aimed to investigate the difference of inter-subjectfunctional connectivity between autistic individuals and neurotypicalcontrols and to evaluate their replication across datasets.