Measurement of brain function during acting

Measurement of Brain Function in Professional Actors Using fNIRS

Importance of the Topic

Functional near-infrared spectroscopy (fNIRS) offers a noninvasive, portable approach to monitor cortical activity during naturalistic tasks. Investigating neural responses in actors provides insight into self-perception and interpersonal coordination under real-world conditions, advancing social neuroscience and applied performance studies.

Objectives and Study Overview

The study aimed to assess how professional actors’ medial prefrontal cortex (mPFC) activity to hearing their own name is modulated during acting versus non-acting conditions, and to evaluate inter-brain coherence between dyads to uncover neural markers of mutual coordination.

Methodology and Instrumentation

Six professional actors (three paired dyads) performed walking, speaking, and scripted acting segments interspersed with “name-call” events over a 20-minute session. Multimodal data collection included:

• Shimadzu LIGHTNIRS wearable fNIRS system (8 input pairs, 22 channels)
• Heart rate and respiration monitoring
• Motion capture belt

fNIRS data were preprocessed in Homer2: conversion to optical density, motion artifact correction, high-frequency noise removal, and extraction of ΔHbO₂ and ΔHbR signals. Analyses comprised:

1. Contrast effects using SPM for fNIRS
2. Brain-to-brain coherence via wavelet transform

Main Results and Discussion

Contrast analysis revealed a robust mPFC response to one’s own name in non-acting conditions, which was suppressed during acting. Wavelet coherence demonstrated significant inter-individual synchrony in the right inferior frontal gyrus (R-IFG) and right frontopolar cortex (R-FPC) within the task frequency band, with no parallel coherence in pulse or respiration. These findings suggest that neural coupling reflects higher-order cognitive coordination (e.g., mutual prediction) rather than shared physiological arousal.

Benefits and Practical Applications

The wearable fNIRS approach enables simultaneous multi-person brain monitoring in dynamic, ecologically valid contexts. It can disentangle neural origins from motion or physiological artifacts and supports applications in:

• Performance neuroscience and theater training
• Team coordination and collaborative work studies
• Brain-computer interface research in group settings

Future Trends and Applications

Advancements may include integration with MRI fusion for anatomical precision, real-time 3D optode localization, expansion to larger ensembles, and incorporation of additional biosignals. These developments will broaden fNIRS utility in clinical rehabilitation, educational environments, and adaptive human-machine systems.

Conclusion

Wearable fNIRS provides a powerful tool to investigate self-referential processing and interpersonal neural dynamics during complex social tasks. The suppression of self-name responses under acting and the emergence of inter-brain coherence in specific prefrontal regions highlight its potential for uncovering the neural basis of group coordination.

References

Greaves DA, Pinti P, Din S, Hickson R, Diao M, Lange C, Khurana P, Hunter K, Tachtsidis I, Hamilton AF de C. Exploring Theater Neuroscience: Using Wearable Functional Near-infrared Spectroscopy to Measure the Sense of Self and Interpersonal Coordination in Professional Actors. Journal of Cognitive Neuroscience. 2022;34(12):2215–2236. DOI:10.1162/jocn_a_01912.