Gut Feelings: Vagal Stimulation Reduces Emotional Biases

Area of Science:

• Neuroscience
• Psychology
• Microbiology

Background:

• The vagus nerve is central to the gut-brain axis, influencing emotion and cognition.
• Gut microbiome alterations affect human emotion, with vagus nerve involvement suggested by animal studies.
• Vagus nerve stimulation is used for severe depression, prompting investigation into its effects on healthy subjects.

Purpose of the Study:

• To investigate if vagal afferent signaling influences emotional processing in healthy individuals.
• To determine the effect of transcutaneous vagus nerve stimulation (tVNS) on attentional biases towards emotional stimuli.

Main Methods:

• A within-subject design was used with 42 healthy volunteers.
• Participants underwent both active and sham transcutaneous vagus nerve stimulation.
• The dot-probe task assessed attentional biases towards emotional stimuli (sadness, happiness).

Main Results:

• Transcutaneous vagus nerve stimulation significantly reduced emotional bias towards faces expressing sadness and happiness.
• This indicates a decrease in emotional reactivity in healthy subjects.
• The effect was most pronounced for sadness-related emotional bias.

Conclusions:

• Vagal signaling, particularly via non-invasive tVNS, can modulate emotional biases in healthy individuals.
• Reduced emotional bias, especially towards sadness, may explain tVNS efficacy in depression treatment.
• tVNS shows potential as a non-invasive adjunctive therapy for depression, complementing existing treatments.