Relief of dyspnea involves a characteristic brain activation and a specific quality of sensation.
BACKGROUND
Central processing of dyspnea relief remains largely unknown.


OBJECTIVE
To identify physiologic determinants, quality of sensation, and brain activation associated with dyspnea relief.


METHODS
Dyspnea relief was induced in 10 healthy volunteers by decreasing an adjustable external resistive load ( approximately 15-50 cm H(2)O/L/s). Brain imaging (positron emission tomography) was performed during either dyspnea or relief.


RESULTS
Perceived intensity of moderate and high relief was similar to that of its preceding dyspnea (Borg scores = 5.10 +/- 1.49 vs. 5.3 +/- 1.4, and 2.78 +/- 0.94 vs. 2.99 +/- 0.94, respectively; P >/= 0.05) and was predominantly related to reversal of dyspnea-induced increased mouth pressure/ventilation ratio (r(2) = 0.88, P < 0.001). Dyspnea relief involved specific, mostly positively valenced descriptors (i.e., breathing-related pleasure and/or reward). Most significant relief-associated brain activation was detected in the left anterior cingulate cortex (Z score = 4.7, corrected P < 0.05) and additional activation (uncorrected P < 0.0001) in the posterior cerebellum and in the temporal and prefrontal cortices. For dyspnea, significant activation was located in the right caudate nucleus, the anterior cerebellum (Z = 5 and 4.65, respectively; corrected P < 0.05), and the premotor cortex, whereas deactivation occurred in the left prefrontal cortex (Z = 4.11).


CONCLUSIONS
Relief of acute load-induced dyspnea is not simply the neutral perception of dyspnea decrease but rather a strong, positively valenced sensation that is associated with characteristic brain activation distinct from that subserving dyspnea perception and possibly reflecting activation of a dyspnea modulation network.
Laboratoire de Physiologie-EFR, Hôpital Saint-Vincent-de-Paul 82, Avenue Denfert Rochereau, 75014 Paris, France. claudinepeiffer@yahoo.fr
Claudine
C
Peiffer
Nicolas
N
Costes
Philippe
P
Hervé
Luis
L
Garcia-Larrea
D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D004417:Dyspnea / Q000503:physiopathology*; D006801:Humans; D008297:Male; D009431:Neural Conduction / Q000502:physiology; D010465:Perception / Q000502:physiology; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D011336:Probability; D012016:Reference Values; D012075:Remission, Spontaneous; D015656:Respiratory Mechanics; D013003:Somatosensory Cortex / Q000502:physiology*