Scientists have identified a brain circuit that helps us control voluntary breathing. This circuit establishes a link between the emotional and behavioral areas of the brain and the automatic breathing center located in the brainstem. These discoveries may provide a pathway for developing treatments to slow breathing in individuals experiencing anxiety, panic disorders, or PTSD, while also highlighting why intentional deep breathing is effective in mindfulness practices such as yoga.
Inhale deeply, exhale slowly. Isn’t it fascinating that we can calm ourselves by breathing more slowly? For generations, people have utilized slow breathing as a means of emotional regulation, with techniques like box breathing gaining traction through yoga and mindfulness. Despite this, scientific exploration into how our brain consciously governs breathing and its impact on our emotional state has been limited.
For the first time, researchers from the Salk Institute have pinpointed a precise brain circuit responsible for regulating voluntary breathing. In their study with mice, they discovered a cluster of neurons within the frontal cortex that connects to the brainstem, the region that manages essential functions like breathing. This link between the more advanced brain areas and the breathing center in the lower brainstem enables us to align our breathing with our emotions and actions.
The research, published in Nature Neuroscience on November 19, 2024, introduces a new set of neural cells and molecules that could be targeted with therapies aimed at controlling breathing during hyperventilation, as well as managing anxiety, panic, and PTSD.
“Our bodies naturally regulate through deep breaths, making it instinctive for us to match our breathing with our emotions — but we were unclear on how exactly this occurred in the brain,” stated Sung Han, senior author of the study and associate professor at Salk. “By identifying a specific brain mechanism that facilitates slower breathing, our findings offer a scientific basis for the beneficial effects associated with yoga and mindfulness in easing negative emotions.”
Linking emotional states and breathing patterns can be complex — when anxiety rises or falls, our breathing rate shifts accordingly. Though this relationship between emotional regulation and breathing seems evident, most prior research focused primarily on subconscious breathing processes controlled by the brainstem. Recent studies have begun to explore conscious mechanisms, yet no specific brain circuits had been identified before the Salk team’s investigation.
The researchers hypothesized that the frontal cortex, known for managing complex thoughts and actions, communicates with the medulla in the brainstem, which governs automatic breathing. To investigate this, they turned to a neural connectivity database followed by experiments to trace connections between these brain regions.
Initial experiments revealed a potentially new breathing circuit: neurons from an area in the frontal cortex known as the anterior cingulate cortex linked to an intermediary area in the pons, which then connected to the medulla underneath it.
In addition to the physical connections, understanding the messaging between these areas is key. When the medulla is active, it prompts breathing to begin. However, signals from the pons can actually suppress activity in the medulla, resulting in slower breathing. The team posited that certain emotions and behaviors might prompt cortical neurons to stimulate the pons, thereby reducing activity in the medulla, leading to a decline in breath rates.
To validate this, researchers monitored brain activity in mice during instances that affect breathing, including actions like sniffing, swimming, and drinking, as well as during heightened fear and anxiety states. They also employed optogenetics to activate or deactivate specific parts of this brain circuit in various emotional contexts while observing the rodents’ breathing and behavior.
The results confirmed that activating the connection between the cortex and the pons led to slower, calmer breathing in mice, whereas anxiety-inducing situations diminished this communication, resulting in increased breath rates. Additionally, artificially stimulating this circuit caused their breath to slow down and significantly reduced anxiety signs. Conversely, disabling the circuit led to faster breathing and heightened anxiety.
Overall, the anterior cingulate cortex-pons-medulla circuit appears to facilitate the voluntary adjustment of breathing in response to emotional and behavioral states.
“These findings raise intriguing possibilities: could we create drugs that activate these neurons to manually control breathing or avert hyperventilation during panic attacks?” mused Jinho Jhang, the study’s lead author and a senior research associate in Han’s lab. “My sister, who has struggled with panic disorder for years, serves as my inspiration for these research pursuits.”
The researchers are set to delve deeper into this circuit to explore whether drugs could activate it, allowing for controlled breathing. They are also working on discovering the reverse circuit tied to rapid breaths, which they believe is also linked to emotions. They hope their results will lead to lasting solutions for individuals suffering from anxiety, stress, and panic disorders that motivate their dedication to this research.
“I envision using these findings to develop a ‘yoga pill,'” Han expressed. “While it may seem far-fetched and translating this research into a commercial treatment will take significant time, we now possess a targeted brain circuit that could inform the creation of therapies designed to rapidly calm breathing and induce a tranquil, meditative state.”
Other contributors to the study include Shijia Liu, Seahyung Park, and David O’Keefe from Salk.
This work received support from the Kavli Institute for Brain and Mind (IRGS 2020-1710).
