Naturalistic Movie Viewing is an Effective Functional Localizer of the Fusiform Face Area in Adolescents with and without Autism

Abstract Task-based “localizer” neuroimaging protocols are often used to identify specific functional areas in individual participants. Conventionally, these tasks can be unengaging, leading to increased motion and scan fatigue, especially for populations which may struggle with lengthy scans. Dynamic, naturalistic stimuli, like entertaining movies, offer a potential alternative with higher participant engagement and improved data quality. Here, we evaluated whether a short Pixar movie, Partly Cloudy, could serve as a reasonable and useful replacement for a traditional fusiform face area (FFA) localizer in a group of adolescents with and without autism spectrum disorder (ASD). We found that individualized FFA localizations derived from a Pixar movie, Partly Cloudy, were largely consistent with those produced by a traditional localizer. Peak activation locations showed no difference between localizer types; measures of activation pattern and magnitude were also largely the same, except that the occipital face area (OFA) demonstrated more task than movie activation and the parahippocampal place area (PPA) demonstrated more movie than task activation. However, applying these FFA individualized ROIs (iROIs) to independent task data revealed that traditional localizer iROIs still produce more face selective activations. We also demonstrated that the movie viewing helps to reduce motion levels in both adolescents with and without autism relative to the traditional localizer task. Hence, while they may not localize face selective regions of the FFA as robustly as traditional task-based localizers, movie localizers may be an appropriate, or even preferable, choice for fMRI studies in populations which struggle to tolerate lengthy scans, such as individuals with autism, and in paradigms that must rapidly localize multiple functional regions.