The "vegetarian brain": chatting with monkeys and pigs?

Area of Science:

• Neuroscience
• Social Cognition
• Dietary Neuroscience

Background:

• Action observation and execution involve fronto-parietal and temporal brain regions.
• Dietary choices, such as vegetarianism and veganism, may influence neural processing of social stimuli.
• Understanding these differences can shed light on the neural basis of social cognition.

Purpose of the Study:

• To investigate if vegetarians and vegans exhibit different brain responses to observed mouth actions compared to omnivores.
• To explore the neural mechanisms underlying the processing of human and animal actions in different dietary groups.
• To examine the role of the action observation-execution matching system in social cognition across diets.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan 20 omnivores, 19 vegetarians, and 21 vegans.
• Participants watched silent videos of mouth actions performed by humans, monkeys, and pigs.
• Analysis focused on functional connectivity and regional brain activity, particularly in relation to social mirroring and the mirror neuron system.

Main Results:

• Vegetarians and vegans showed increased fronto-parietal/temporal to cerebellum connectivity during observation of mouth actions in humans and animals compared to omnivores.
• Vegans exhibited increased connectivity with the supplementary motor area.
• Increased amygdala activity was observed in vegetarians and vegans during human mouth actions, with specific recruitment of social mirroring and mirror neuron system regions.

Conclusions:

• Dietary choices influence the neural processing of observed actions, impacting social cognition.
• The findings support the action observation-execution matching system's role in social interactions, extending to phylogenetically related species.
• Vegetarian and vegan diets may modulate brain networks involved in empathy and social mirroring.