Breathing is a seemingly simple, essential behavior that rhythmically occurs about 12 times per minute. The pace and pattern of the breathing rhythm originates from a small cluster of ~4000 neurons, in the brainstem called the preBötzinger Complex (preBötC). One of the most amazing features of breathing is how robust, yet flexible it is. Our breathing is always adapting to what we are doing. However, it also appears that breathing can influence what we are doing and how we feel. Just a couple of slow, calm breaths will illustrate this and we are just beginning to understand the direct neural pathways responsible.
We have a very detailed understanding of the body's other key pacemaker, the cardiac pacemaker, and as a result, many thousands of individuals take medications each day to control their heart rate or forcefulness of contraction. In contrast, the cellular and molecular basis for preBötC rhythm generation remains a mystery and as a result, we rely upon mechanical, as opposed to pharmacological, approaches for regulating breathing. One aim of our research is to molecularly define all the neural types within the preBötC and then use sophisticated genetic approaches to study their roles in breathing, in animal model systems. Some examples include, ~70-140 neurons that suppress the breathing rhythm in response to opioids and ~200 neurons that change the pattern of breathing from a normal breath type into a sigh breath. We hope this work will pave the path for developing precise pharmacological control of breathing, which could help treat some of the most common, as well as the most devastating diseases in medicine, like sleep apnea and sudden infant death respectively.
Another interest of our lab is how breathing is modulated and coordinated during other innate behaviors like crying, laughing, and swallowing that are encoded by neighboring brainstem central pattern generators. Studying these behaviors allows us to investigate how two independent central pattern generators couple to generate a single coordinated behavior, e.g. how does a vocalization occur at the correct part of the breathing phase?
In our previous work, we identified a novel neural circuit that enables the breathing rhythm to be directly communicated throughout the brain. This pathway is important for regulating our arousal or emotional state and may perhaps explain how fast breathing makes us feel anxious or slow breathing calms us. We are interested in continuing to explore the diversity and purpose of these non-motor pathways stemming from the preBötC.