eLife Assessment
This manuscript presents a novel investigation of organizational principles governing brain activity at both global and local scales during naturalistic viewing paradigms, an important advance for theoretical neuroscience, functional neuroimaging, and neurology. The authors demonstrate that brain activity during naturalistic viewing is dominated by two anti-correlated states that toggle between each other with a third transitional state mediating between them. The evidence supporting this finding is compelling, with the successful replication across three independent datasets (StudyForrest, NarrattenTion, and CamCAN) a particular strength.