Neuroimaging of central breathlessness mechanisms.
Pattinson KT., Johnson MJ.
PURPOSE OF REVIEW: Breathlessness debilitates millions of people with cardiorespiratory conditions and cancer. Symptoms correlate poorly with the objective measures of disease (e.g. spirometry). Altered brain processing of respiratory sensations may contribute to this disparity. This article summarizes how functional neuroimaging works, focussing on functional MRI (FMRI) and magnetoencephalography, how neuroimaging has shed light on the central mechanisms of breathlessness and thus how it may help target new therapies. RECENT FINDINGS: Current understanding of central neural activity in breathlessness comes mainly from a small number of studies in healthy volunteers using models of induced acute breathlessness. Parallels with neuroimaging findings in pain and fear or anxiety have been used to interpret the neuroimaging studies of breathlessness to form hypotheses. Despite the lack of recent neuroimaging studies in breathlessness, there have been methodological advances in overcoming confounders with respiratory FMRI. In addition, developing interest in the distinction of emotional from the sensory aspects of breathlessness and the use of opioids for breathlessness has driven mechanistic understandings. SUMMARY: Neuroimaging of breathlessness remains in its infancy. However, advances in the understanding of central perception, combined with novel neuroimaging techniques, means that we are poised to increase our understanding of the brain processes of breathlessness and their modulation.