Prefrontal cortex activation during incremental inspiratory loading in healthy participants

Respir Physiol Neurobiol. 2022 Feb:296:103827. doi: 10.1016/j.resp.2021.103827. Epub 2021 Nov 20.

Abstract

We aimed to investigate whether changes in prefrontal cortex (PFC) oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb) associates with inspiratory muscle effort during inspiratory threshold loading (ITL) in healthy participants. Participants performed an incremental ITL. Breathing pattern, partial pressure of end-tidal CO2 (PETCO2), mouth pressure and O2Hb and HHb over the right dorsolateral PFC, sternocleidomastoid (SCM), and diaphragm/intercostals (Dia/IC) were monitored. Fourteen healthy participants (8 men; 29 ± 5 years) completed testing. Dyspnea was higher post- than pre-ITL (5 ± 1 vs. 0 ± 1, respectively; P<0.05). PFC O2Hb increased (P < 0.001) and HHb decreased (P = 0.001) at low loads but remained stable with increasing ITL intensities. PFC total hemoglobin increased at task failure compared to rest. SCM HHb increased throughout increasing intensities. SCM and Dia/IC total hemoglobin increased in the at task failure compared to rest. PETCO2 did not change (P = 0.528). PFC is activated early during the ITL but does not show central fatigue at task failure despite greater dyspnea and an imbalance of SCM oxygen demand and delivery.

Keywords: Breathing exercise; Central fatigue; Near-infrared spectroscopy; Prefrontal cortex; Respiratory muscle.

MeSH terms

  • Adult
  • Breathing Exercises
  • Dyspnea / metabolism*
  • Fatigue / metabolism*
  • Female
  • Healthy Volunteers
  • Hemoglobins / metabolism*
  • Humans
  • Inhalation / physiology*
  • Male
  • Oxygen Consumption / physiology*
  • Oxyhemoglobins / metabolism*
  • Prefrontal Cortex / diagnostic imaging
  • Prefrontal Cortex / metabolism*
  • Respiratory Muscles / metabolism*
  • Spectroscopy, Near-Infrared
  • Young Adult

Substances

  • Hemoglobins
  • Oxyhemoglobins
  • deoxyhemoglobin