Altered parasympathetic outflow and central sensitization response to continuous pain in cyclic vomiting syndrome: a functional magnetic resonance imaging study

Patients with cyclic vomiting syndrome exhibit multiple alterations in central function in response to a sustained pressure-pain stimulus, including altered high-frequency heart rate variability and associated changes in BOLD fMRI signal in key areas of the central autonomic and interoceptive networks, as well as abnormal temporal summation of pain associated with altered connectivity patterns between the primary somatosensory cortex and key regions associated with interoception.