A V0 core neuronal circuit for inspiration.

Area of Science:

• Neuroscience
• Respiratory Physiology

Background:

• Mammalian breathing depends on synchronized contractions of inspiratory muscles, driven by brainstem neural circuits.
• The precise origins and organization of these circuits, particularly inspiratory premotor neurons, are not fully understood.

Purpose of the Study:

• To elucidate the developmental origins, neurotransmitter phenotype, and connectivity of phrenic premotor neurons.
• To identify the specific neural populations and synaptic connections critical for coordinating inspiratory muscle activity.

Main Methods:

• Utilized a virus-based transsynaptic tracing strategy starting from the diaphragm muscle in mice.
• Employed circuit-mapping approaches to reveal neuronal lineage and connectivity patterns.

Main Results:

• Identified principal inspiratory premotor neurons as sharing V0 identity with neurons of the preBötzinger complex.
• Demonstrated that deleting commissural projections of V0 neurons leads to desynchronized inspiratory motor commands and impaired breathing.
• Revealed V0 to V0 synapses are crucial for both rhythm generation and coordinated output to inspiratory muscles.

Conclusions:

• Established the existence of a core inspiratory circuit involving V0 neurons and the preBötzinger complex.
• Highlighted the critical role of V0 neuron connectivity in ensuring bilaterally coordinated inspiratory muscle contractions for efficient breathing.