Science & Nature

The Second Brain

How the Trillions of Microbes in Your Gut Are Shaping Your Mind

John Cryan

Neuroscientist at University College Cork, specializing in the gut-brain axis and the role of the microbiome in mental health. He is one of the world's leading experts on the microbiome-gut-brain connection.

March 10, 2026·8 min read

The Second Brain

The gut microbiome — the community of trillions of microorganisms living in the digestive tract — is emerging as a major influence on brain function and mental health. The gut-brain axis, a bidirectional communication system between the gut and the brain, may play a role in depression, anxiety, autism, and even neurodegenerative diseases.

TOPICS

microbiomegut-brain axisneurosciencemental healthbiology

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