The effect of interbrain synchronization in gesture observation: A fNIRS study

Area of Science:

• Neuroscience
• Cognitive Science
• Social Neuroscience

Background:

• Nonverbal communication through gestures is fundamental to human interaction.
• Understanding the neural basis of gesture observation and its role in social cognition is crucial.
• Previous research suggests mirroring mechanisms in brain areas involved in gesture observation and planning.

Purpose of the Study:

• To investigate the neural mechanisms underlying the observation of affective, social, and informative gestures with varying valence.
• To explore brain activation and interbrain connectivity during dyadic gesture observation using functional Near-Infrared Spectroscopy (fNIRS).

Main Methods:

• Employed a hyperscanning paradigm with fNIRS to simultaneously record brain activity (oxygenated and deoxygenated hemoglobin) in encoders and decoders.
• Analyzed variations in brain responsiveness and interbrain connectivity during the observation of different gesture types and valences.

Main Results:

• Gesture type significantly influenced brain activation and interbrain connectivity, with affective and social gestures showing distinct patterns.
• Affective gestures led to increased oxygenated hemoglobin (O2Hb) and interbrain connectivity, and decreased deoxygenated hemoglobin (HHb) in the dorsolateral prefrontal cortex (DLPFC).
• Social gestures showed increased O2Hb and connectivity in the superior frontal gyrus (SFG).
• Positive affective gestures, compared to negative ones, resulted in heightened O2Hb activity and connectivity in the left DLPFC.

Conclusions:

• The study demonstrates differential neural responses to the observation of various positive and negative gestures.
• Interbrain connectivity analysis highlights mirroring mechanisms in frontal regions during gesture observation and action planning.
• Findings contribute to understanding the neural underpinnings of nonverbal communication and social cognition.