Rhesus macaques are able to perceive their own heartbeats, according to a new study from the California National Primate Research Center at the University of California, Davis, and Royal Holloway, University of London. The research, published April 11 in Proceedings of the National Academy of Sciences creates a first-of-its-kind animal model of interoception. Interoception refers to the ability to sense the internal state of one's body, such as observing when your heart races or breathing quickens. The findings provide an important model for future psychiatric and neuropsychiatric research as dysfunctions in interoception are associated with anxiety, depression, and Alzheimer's disease.