We’ve never fully understood it before. But there’s simply something about breathing deeply and slowly that makes one calm down. It’s what your parents, your teachers, healthcare providers, and practically everyone else around you advises you to do when you’re overly stressed, or you’re raving mad, or you’re simply at the height of some extreme emotion. It’s also one of the core elements in yoga and meditation. It’s referred to as pranayama — the practice of doing controlled breathing so one’s consciousness will be able to shift from an agitated to a meditative state.
Somehow, deep and slow breathing induces calmness. Now, the mystery behind it has been solved.
According to a team of scientists at the Stanford University School of Medicine, it has to do with a specific group of neurons in the brain which have been identified as the connection between one’s breathing and state of mind. The cluster of neurons is referred to as the ‘respiratory pacemaker’ (technically the pre-Bötzinger complex) and it links breathing with anxiety, attention, excitement and relaxation. It was discovered in a mouse study in 1991, but was later on found to exist in humans as well.
To arrive at their findings, the research team led by Dr. Kevin Yackle (a faculty fellow at the University of California-San Francisco) conducted lab tests on mice. They wanted to find out if different types of neurons within the ‘respiratory pacemaker’ regulate a different kind of breathing — regular, excited, yawning, sleeping, sighing, gasping, sobbing and laughing — and if such are also linked in some way to emotional and social signals.
It was a kind of trial-and-error experiment. Selectively destroying any of the neuron subtypes was meant to show how the loss of these neurons affected the mice’s breathing.
In a previous study (involving Mark Krasnow, a biochemistry professor at Stanford University who is also a senior author in this latest study), researchers were already able to show that by removing a specific set of neurons within the ‘respiratory pacemaker’, mice lost their ability to sigh.
This time, Dr. Yackle’s team removed a different set of neurons. A few days passed and nothing happened. However, when they placed the mice in different surroundings, the effect of their experiment began to show.
Instead of the normal behavior that’s expected of mice placed in a new environment, that is, actively sniffing and exploring, they seemed surprisingly ‘cool and tranquil’. They mostly just sat around, and they were often breathing slowly (which was associated with ‘chilling out’).
This led the team to believe that they may have hit the respiratory pacemaker’s ‘calming’ group of neurons. Their theory is that instead of regulating breathing, these neurons were like ‘spies’ — they observe, then report what they see to the locus coeruleus.
As they explained in a press release: ‘This structure, the locus coeruleus, sends projections to practically every part of the brain and drives arousal: waking us from sleep, maintaining our alertness and, if excessive, triggering anxiety and distress.’
To cut a long story short, the more ‘reports’ these neuron spies send to the locus coeruleus, the more ‘aroused’ or ‘excited’ the mouse becomes. The lesser ‘reports’ sent, the calmer and more laid back the mouse becomes.
The team is hopeful that their findings will lead to the development of new and possibly better therapies for depression, stress and other negative emotions. Moving forward, they are planning to study other neurons in the respiratory pacemaker to see what other functions they may uncover.
The paper detailing the findings was recently published in the journal Science under the title “Breathing control center neurons that promote arousal in mice”.