Summary: The study reveals a potential link between breathing and changes in neural activity in animal models.
Font: State of Pennsylvania
Mental health professionals and meditation gurus have long credited intentional breathing with the ability to induce inner calm, but scientists don’t fully understand how the brain is involved in the process.
Using functional magnetic resonance imaging (fMRI) and electrophysiology, researchers at the Penn State College of Engineering identified a potential link between respiration and changes in neural activity in rats.
Their results were made available online prior to publication in eLife. The researchers used simultaneous multimodal techniques to remove noise typically associated with brain imaging and pinpoint where breathing regulated neural activity.
“There are approximately one million articles published on fMRI, a noninvasive imaging technique that allows researchers to examine brain activity in real time,” said Nanyin Zhang, founding director of Penn State’s Center for Neurotechnology in Mental Health Research and professor of biomedical sciences. engineering.
“Imaging researchers used to believe that breathing is a non-neural physiological artifact, like a heartbeat or body movement, on fMRI. Our paper introduces the idea that breathing has a neural component: it affects the fMRI signal by modulating neural activity.”
By scanning the brain waves of resting-state rodents under anesthesia using fMRI, the researchers revealed a network of brain regions involved in breathing.
“Breathing is a need common to almost all living animals,” said Zhang. “We know that breathing is controlled by a region in the brainstem. But we didn’t have a complete picture of how breathing affects other regions of the brain.”
Along with fMRI, the researchers used neural electrophysiology, which measures electrical properties and signals in the nervous system, to link respiration to neural activity in the cingulate cortex, a brain region in the center of the cerebral hemisphere associated with emotional response and regulation.
Simultaneous use of fMRI and electrophysiology allowed the researchers to detect non-nerve related fMRI signal changes during data collection, such as movement and carbon dioxide exhalations.
The findings provide insight into how neural activity and fMRI signals are linked in the resting state, Zhang said, which could inform future imaging research to understand how neurovascular signals change at rest.
“While the animals were breathing, we measured how their brain activity fluctuated with their rate of breathing,” said Zhang. “When extended to humans, this approach could provide mechanistic insights into how breath control common to meditative practices can help reduce stress and anxiety.”
The correlation between neural activity in the cingulate cortex and respiratory rhythm may indicate that respiratory rhythms can affect emotional state, according to Zhang.
“When we are in a state of anxiety, our breathing often quickens,” Zhang said. “In response, we sometimes take deep breaths. Or when we are focusing, we tend to hold our breath. Those are signs that breathing can affect our brain function. Breathing allows us to control our emotions, for example, when we need our brain function to be altered. Our findings support that idea.”
Future studies may focus on looking at the brain in human subjects while they meditate to look at the more direct connection between slow, intentional breathing and neural activity, according to Zhang.
“Our understanding of what happens in the brain is still sketchy,” said Zhang. “If the researchers replicate the study in humans using the same techniques, they could explain how meditation modulates neural activity in the brain.”
About this neuroscience research news
Author: mariah chuprinsky
Font: State of Pennsylvania
Contact: Mariah Chuprinski – Penn State
Image: The image is in the public domain.
original research: Open access.
“Neural support of a respiration-associated resting-state fMRI network” by Wenyu Tu et al. eLife
Neural basis of a breathing-associated resting-state fMRI network
Breathing can induce movement and COtwo fluctuation during resting-state fMRI (rsfMRI) scans, which will lead to non-neural artifacts in the rsfMRI signal. Meanwhile, as a crucial physiological process, breathing can directly drive neuronal activity change in the brain and thus can modulate the rsfMRI signal.
Nonetheless, this potential neural component in the breath-fMRI relationship is largely unexplored. To clarify this issue, here we simultaneously recorded electrophysiology, rsfMRI, and respiration signals in rats.
Our data show that respiration is indeed associated with changes in neuronal activity, evidenced by a phase-locked relationship between slow respiration variations and the power of the gamma band of the electrophysiological signal recorded in the anterior cingulate cortex.
Interestingly, slow breathing variations are also linked to a characteristic rsfMRI network, which is mediated by gamma band neuronal activity. Furthermore, this respiration-related brain network disappears when neural activity throughout the brain is silenced in an isoelectric state, while breathing is sustained, further confirming the necessary role of neural activity in this network.
Taken together, this study identifies a respiration-related brain network underpinned by neural activity, which represents a novel component in the respiration-rsfMRI relationship that is distinct from respiration-related rsfMRI artifacts. It opens a new avenue to investigate the interactions between respiration, neural activity, and resting-state brain networks in both healthy and diseased conditions.
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