RT Journal Article
SR Electronic
T1 Cortical processing of breathlessness in the athletic brain
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 174052
DO 10.1101/174052
A1 Olivia K. Faull
A1 Pete J. Cox
A1 Kyle T. S. Pattinson
YR 2017
UL http://biorxiv.org/content/early/2017/08/09/174052.abstract
AB Key pointsEndurance athletes train to improve their respiratory system for enhanced exercise capacity and performance. However, it is unknown whether concurrent adaptation occurs in brain networks perceiving respiratory-related sensations, such as breathlessness.We have previously shown improved matching between changes in ventilation and perceptions of breathlessness in endurance athletes compared to sedentary controls (Faull et al., 2016a). Here, we used functional brain scanning to investigate differences in brain activity during breathlessness tasks in these subjects.Athletes demonstrated a network of brain activity during anticipation of resistive inspiratory loading that corresponds to subjective breathlessness intensity, which was absent in sedentary controls. This may be related to improved brain synchronicity observed between primary sensorimotor cortices and task-positive brain networks in these athletes, and may underpin our previous findings of improved ventilatory interoception.Understanding brain changes in respiratory perceptions may help us to target both endurance training mechanisms and treatment of disease-related breathlessness symptomology.Abstract Exercise is associated with large increases in ventilation, which are consciously perceived as the sensation of breathlessness. We have previously demonstrated closer matching between changes in ventilation and corresponding perceptions of breathlessness in endurance athletes compared with sedentary controls (Faull et al., 2016a), suggesting improved accuracy when interpreting respiratory sensations, or ventilatory interoception. Here, we sought to identify the mechanisms by which the processing of respiratory perception is optimised in these subjects.Forty participants (20 athletes, 20 age/sex-matched sedentary participants) were scanned using a 7T Siemens Magnetom (Nova Medical 32 channel Rx, single channel birdcage Tx). Anticipation and breathlessness were induced with a previously trained delay-conditioned cue and an inspiratory resistance during fMRI scanning. Differences between group means and slope of subjective scores during task-based and resting fMRI were analysed using non-parametric statistical testing and independent component analysis.Athletes demonstrated greater brain activity corresponding with intensity scores during anticipation of breathlessness, compared to sedentary controls. Athletes also exhibited greater functional connectivity (or communication) between a task-positive brain network closely matching breathlessness activity, and areas of primary sensorimotor cortices active during inspiratory resistance. These functional activity and connectivity differences in athletic brains may represent optimized processing of respiratory sensations, and contribute to improved ventilatory interoception in athletes. Furthermore, these brain mechanisms may be harnessed when exercise is employed in the treatment of breathlessness for chronic respiratory disease.