Human cerebral activity with increasing inspiratory force: a study using positron emission tomography

Area of Science:

• Neuroscience
• Physiology
• Respiratory Medicine

Background:

• Understanding the neural control of breathing is crucial for respiratory medicine.
• Inspiratory muscle force is a key component of respiratory mechanics.
• Previous studies have indicated brain activation during breathing tasks.

Purpose of the Study:

• To investigate the dose-dependent effects of inspiratory loads on human cerebral activity.
• To map regional cerebral blood flow changes using Positron Emission Tomography (PET) as a proxy for neuronal activation.
• To identify specific brain regions involved in the volitional control of inspiratory force.

Main Methods:

• Six healthy males participated in the study.
• H2 15O-PET scans were performed during unloaded breathing and with increasing inspiratory loads (-5, -10, -15 cmH2O).
• Positive-pressure ventilation served as a control condition.

Main Results:

• Unloaded breathing activated the supplementary motor area.
• The smallest inspiratory load recruited the right premotor area and bilateral motor cortex (MI).
• Greater loads showed additional activation in the sensorimotor cortex, parietal cortex, and midbrain/hypothalamus.

Conclusions:

• Volitionally increasing inspiratory muscle force involves complex neural integration.
• Both cortical and subcortical brain regions are recruited for enhanced inspiratory effort.
• PET imaging provides valuable insights into the neurobiology of respiratory control.