Prefrontal cortex activation during incremental inspiratory loading in healthy participants

Area of Science:

• Physiology
• Neuroscience
• Respiratory Medicine

Background:

• Inspiratory muscle effort is crucial for breathing.
• Understanding the neural correlates of respiratory loading is important for managing respiratory conditions.

Purpose of the Study:

• To investigate the association between prefrontal cortex (PFC) oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) and inspiratory muscle effort during incremental inspiratory threshold loading (ITL) in healthy individuals.

Main Methods:

• Fourteen healthy participants underwent incremental ITL.
• Measurements included breathing pattern, end-tidal CO2 (PETCO2), mouth pressure, and NIRS-measured O2Hb and HHb in the PFC, sternocleidomastoid (SCM), and diaphragm/intercostals (Dia/IC).

Main Results:

• Dyspnea increased significantly post-ITL.
• PFC O2Hb increased and HHb decreased at low ITL loads, with stable levels at higher intensities.
• SCM HHb increased with ITL intensity, while SCM and Dia/IC total hemoglobin increased at task failure.
• PFC total hemoglobin increased at task failure, but PETCO2 remained unchanged.

Conclusions:

• The PFC is activated early during ITL.
• Despite increased dyspnea and altered peripheral muscle oxygenation, the PFC does not exhibit central fatigue at task failure during ITL in healthy individuals.