Every breath you take does more than deliver oxygen – it helps organize activity throughout the brain. University of Iowa neuroscientists have shown, for the first time, that the rhythm of breathing synchronizes widespread brain activity in humans whether they are awake, asleep, or even breathing via a mechanical ventilator. This synchronization suggests that breathing serves as a fundamental organizing signal for widespread human brain networks.
Led by Brian Dlouhy, MD, UI associate professor of neurosurgery, and published in Nature Communications, this study is the largest direct human intracranial study of breathing and brain activity, with recordings from more than 1,200 brain sites.
“Our work shows that breathing isn't just controlled by the brain, it also continuously shapes how the brain functions,” Dlouhy says. “It’s remarkable how much of the brain seems to be entrained by breathing rhythm.”
These findings open new avenues for exploring the connection between breathing and many different brain functions and diseases including emotion, cognition, sleep disorders, epilepsy, SUDEP, and other neurological conditions.
A large number of pediatric deaths come from these sudden deaths while sleeping. For some reason, the alarm bells in the brain aren’t triggered when breathing stops. A better understanding of the circuitry that connects breathing and brain activity could help us to fix that. - Brian Dlouhy, MD
Deep brain recordings reveal how breathing shapes brain activity
Dlouhy and his team worked with patients who were undergoing surgical treatment for epilepsy. Neurosurgeons seeking to determine the location of seizure activity within the brain used intracranial electroencephalography, a specialized procedure that uses implanted electrodes to record electrical activity directly from the human brain.
“We leveraged unique clinical conditions where participants experienced different states of wakefulness and airflow delivery methods during clinical care,” Dlouhy says. “The unique set up we have here for human intracranial recordings allows us to ask these important questions.”
Dlouhy’s team recorded breathing while the patients were awake and asleep to determine whether neural oscillations in the forebrain synchronized with the breathing rhythm. They found synchronization with breathing across multiple brain sites while awake, and primarily in the hippocampus and amygdala while asleep.
Some patients required a period of mechanical ventilation, allowing the team to record breathing controlled by the ventilator independent of the forebrain or brainstem. They found that even while the ventilator controlled breathing, neural oscillations synchronized with the breathing rhythm, confirming that it is the in-and-out rhythm of breathing that entrains the brain activity. Further, they found that using slow, deep ventilation—mimicking the type of deep breathing commonly recommended for calming and emotional regulation—entrained a larger portion of the forebrain.
“This heightened neural entrainment highlights the remarkable adaptability of forebrain circuits to varying respiratory inputs,” Dlouhy says. “These findings hold broad implications and may lead to better understanding and treatment for disorders of respiratory awareness, emotional regulation, and cognitive health.”
Crucially, pinpointing the connection between breathing and brain function during sleep could lead to insights into sleep-related disorders and sudden death syndromes like sudden infant death syndrome (SIDS) and sudden unexpected death in epilepsy (SUDEP.).
“A large number of pediatric deaths come from these sudden deaths while sleeping,” Dlouhy says. “For some reason, the alarm bells in the brain aren’t triggered when breathing stops. A better understanding of the circuitry that connects breathing and brain activity could help us to fix that.”
The research team included first-author Md Rakibul Mowla, a postdoctoral scholar in neurosurgery; research and clinical staff: Ariane E. Rhone, Justin D. Kuhn, and Ryan T. Frede; UI faculty: Sukhbinder Kumar, Christopher K. Kovach, Junjie V. Liu, Aubrey C. Chan, Hiroto Kawasaki, Rashmi N. Mueller, Michael A. Ciliberto, Theresa M. Czech, Sreenath Thati Ganganna, James W. Owens, Ania K. Dabrowski, Brittany N. Sprigg, Mark A. Granner, Kirill V. Nourski, Matthew A. Howard III, George B. Richerson, John A. Wemmie; and collaborators from Harvard University, University of Florida, University of Oxford (U.K.) and University of Wisconsin—Madison.
Funding for this study came from the National Institutes of Health, National Institute of Health Research (NIHR) Biomedical Research Centre based at Oxford University Hospitals NHS Trust and the University of Oxford, Roy J. Carver Charitable Trust, and the U.S. Department of Veterans Affairs.