Auricular transcutaneous vagus nerve stimulation stabilizes event segmentation through modulation of working memory...

Area of Science:

• Cognitive Neuroscience
• Neurostimulation
• Human Neurophysiology

Background:

• Event segmentation, the process of dividing continuous experience into discrete units, is crucial for situational awareness and adaptive behavior.
• Event Segmentation Theory (EST) posits that norepinephrine (NE) and GABAergic systems play roles in controlling event segmentation.
• Auricular transcutaneous vagus nerve stimulation (atVNS) offers a non-invasive method to modulate neural systems.

Purpose of the Study:

• To investigate whether atVNS influences event segmentation.
• To explore the potential moderating roles of norepinephrine and/or GABAergic systems in event segmentation.
• To examine the neural mechanisms underlying atVNS effects on event segmentation using EEG.

Main Methods:

• A double-blind, counterbalanced experiment with 40 healthy adults.
• Participants watched a movie and indicated event boundaries during active atVNS and sham stimulation.
• EEG recorded neural activity; Multivariate Pattern Analysis (MVPA) assessed neural pattern distinctiveness; source reconstruction identified cortical activation.

Main Results:

• Active atVNS significantly reduced the likelihood of event segmentation compared to sham stimulation.
• MVPA showed lower decoding accuracy for boundary and non-boundary intervals, indicating less distinct neural representations.
• EEG source reconstruction revealed reduced activation in the prefrontal cortex, associated with working memory.

Conclusions:

• atVNS stabilizes event representation and restricts the updating of working models, suggesting GABAergic modulation of event segmentation.
• Findings align with previous research linking atVNS to working memory gating.
• atVNS impacts the ecologically relevant cognitive process of event segmentation.