Dyspnea (shortness of breath, breathlessness) is a major and disabling symptom of heart and lung disease. The representation of dyspnea in the cerebral cortex is unknown. In the first study designed to explore the central neural structures underlying perception of dyspnea, we evoked the perception of severe ‘air hunger’ in healthy subjects by restraining ventilation below spontaneous levels while holding arterial oxygen and carbon dioxide levels constant. PET revealed that air hunger activated the insular cortex. The insula is a limbic structure also activated by visceral stimuli, temperature, taste, nausea and pain. Like dyspnea, such perceptions underlie behaviors essential to homeostasis and survival.
1Department of Medicine, Harvard Medical School and Physiology Program, Harvard School of Public Health, 665 Huntington Ave, Boston, MA, 2115 USA
2MRC Cyclotron Unit, Imperial College School of Medicine, London, UK
3Department of Respiratory Medicine, NHLI Division, Imperial College School of Medicine, London, UK
4Corresponding Author: Robert B. Banzett
Acknowledgements: Supported by the US National Institutes of Health HL46690, The Breathlessness Research Charitable Trust, and the UK Medical Research Council. We thank our subjects, A. Blyth and the team at MRC Hammersmith Cyclotron unit, and Drs R.W. Lansing, A. Guz, D. Paydarfar, T.A. McMahon, and M.C. Bushnell.
Received 21 March 2000; accepted 20 April 2000