Movie-watching

Journal: Nature Communications Title: Movie-watching evokes ripple-like activity within events and at event boundaries Authors: Marta Silva, Xiongbo Wu, Marc Sabio, Estefanía Conde-Blanco, Pedro Roldán, et al. Date: 1 July 2025 DOI: 10.1038/s41467-025-60788-0 Study type: Human intracranial electrophysiology (observational / exploratory)

To investigate whether ripple-like activity (a neural oscillatory pattern ~80–120 Hz, known from hippocampal sharp-wave ripples) occurs in humans during naturalistic experiences, particularly during movie watching, and whether such ripples align with event boundaries and within-event saliency.

• Participants: 14 epilepsy patients undergoing iEEG (intracranial EEG).
• Stimuli: Narrative films with annotated event boundaries.
• Analysis:
  • Detection of ripple-like events in medial temporal lobe (MTL) and other regions.
  • Temporal alignment with annotated cognitive events.
  • Comparison of ripple rate and power across boundary vs. within-event segments.

• Ripple-like activity increases at event boundaries, suggesting encoding or segmentation functions.
• Ripples also increase within events, especially during emotionally or perceptually salient moments.
• Stronger ripple coupling was observed across MTL and high-level cortical regions (e.g., precuneus, medial PFC).

• Epilepsy bias: All subjects were patients with drug-resistant epilepsy, which may affect generalizability.
• Correlational design: Cannot determine causal role of ripples in perception or memory.
• Ripple detection thresholds: May vary across individuals and cortical regions; risk of false positives or artifact contamination.

• Supports the idea that cognitive event segmentation in naturalistic contexts involves ripple-like neural dynamics.
• Provides evidence that memory-related oscillations are not restricted to sleep or explicit tasks, but extend to real-life experiences.
• Suggests new approaches to studying human cognition through naturalistic paradigms (e.g., movies) rather than artificial tasks.

This exploratory iEEG study provides compelling evidence that ripple-like activity is modulated by narrative event structure during passive movie-watching. It contributes to bridging the gap between controlled cognitive neuroscience and real-world neural processing, though replication in non-clinical populations and mechanistic work is still needed.