Roughly 80% of vagus nerve fibers carry sensory information from organs to brain — not commands from brain to body. The tenth cranial nerve, named from Latin 'vagus' (wandering), is the longest nerve outside the spinal cord and the master switch of the parasympathetic 'rest and digest' system, modulating heart rate, digestion, breathing, mood, and inflammation.
Each round presents 10 randomized questions from a pool of 50, with four multiple-choice options and instant feedback after every answer. Your final score comes with a performance tier and shareable results.
You'll explore vagal anatomy, the parasympathetic system, heart rate variability, polyvagal theory, vagus nerve stimulation (VNS) therapy, and natural ways to tone the vagus — from cold exposure and humming to slow diaphragmatic breathing.
It governs much of the parasympathetic 'rest and digest' system: heart rate, digestion, breathing, vocalization, and the cholinergic anti-inflammatory pathway.
Slow diaphragmatic breathing (long exhale), cold face immersion, humming, singing, gargling, meditation, and yoga all increase vagal tone.
Stephen Porges's 1994 evolutionary model proposing two functional vagal branches: ventral (myelinated, social engagement) and dorsal (unmyelinated, immobilization/freeze). Influential in trauma therapy though debated in mainstream neuroscience.
Last updated: April 2026