Role of inhibition in respiratory patterning

Role of inhibition in respiratory patterning

Life Sciences

Sammi Hung

2024

Robert T. R. Huckstepp

The overall aim of this project is to characterise how inhibitory neurons in the respiratory rhythm generating microcircuit influence expiration. Breathing in mammals is a fundamental behaviour produced by movements generated and controlled by the central nervous system. There are 3 oscillators responsible for respiratory rhythmogenesis and pattern formation: one each for inspiration, post-inspiration, and expiration. Given the number of subpopulations of neurons within the respiratory rhythm generating microcircuit, the experiments focus on the possible sources of inhibition to the expiratory oscillator and the excitatory populations that may drive these inhibitory neurons. Reciprocal inhibitory coupling prevents the respiratory phases from being coactive. However, the role of this inhibitory coupling appears to be much more than simply sequencing the different phases of breathing. Firstly, inhibitory neurons within the inspiratory oscillator increase burst probability and co-ordinate inspiratory firing. Secondly, expiration is generated by post-inhibitory rebound, with excitatory drive playing a subsidiary role. Whilst the source of inhibition within the inspiratory oscillator is known, the neurons inhibiting the expiratory oscillator remain elusive, and are the focus of this investigation. Whereas inspiratory and expiratory oscillators contain inhibitory neurons, inhibitory interneurons are apparently absent from the post-inspiratory oscillator. Therefore post-inspiratory mediated inhibition of the expiratory oscillator must occur through a relay nucleus.

Science, Medicine, Breathing, Respiration, Respiratory patterning