Defining the neurocircuitry of exercise hyperpnoea

Area of Science:

• Neuroscience
• Exercise Physiology

Background:

• Krogh and Lindhard's 1913 paper emphasized the brain's role in exercise breathing control.
• Exercise hyperpnoea, or increased breathing during exercise, is influenced by central command.
• Recent advances in neuroimaging and neurosurgery offer new ways to study these brain circuits in humans.

Purpose of the Study:

• To review historical developments in understanding the brain's control of breathing during exercise.
• To identify key brain structures involved in the central command network for exercise hyperpnoea.
• To integrate findings from animal studies and human recordings to pinpoint critical neural circuits.

Main Methods:

• Review of historical literature on respiratory control during exercise.
• Analysis of neuroimaging and functional neurosurgical data in humans.
• Electrophysiological recordings from mid-brain structures (subthalamic nucleus, periaqueductal grey) during exercise in humans.

Main Results:

• The periaqueductal grey (PAG), particularly its lateral and dorsal lateral aspects, is identified as a key component of the central command network.
• The PAG demonstrates functional connectivity with higher cognitive centers (dorsal lateral prefrontal cortex) and basal ganglia (subthalamic nucleus).
• The PAG receives sensory input from exercising muscles and projects to brainstem nuclei regulating cardiorespiratory function.

Conclusions:

• The periaqueductal grey (PAG) plays a crucial role in central command during exercise.
• The PAG integrates sensory information and motor commands to regulate breathing and cardiovascular responses during physical activity.
• These findings provide a framework for understanding the neural basis of exercise hyperpnoea and its control mechanisms.