The brain coordinates speaking and breathing by controlling different areas of the brain responsible for these functions.
In a groundbreaking study conducted by researchers at the Massachusetts Institute of Technology (MIT), a novel brain circuit responsible for coordinating speaking and breathing has been unveiled. The circuit ensures that breathing takes precedence over speaking, allowing individuals to talk only when exhaling and stopping conversation during inhalation.
The newly discovered circuit is crucial for two essential components of vocalization: the narrowing of the larynx and the exhalation of air from the lungs. It was found that this vocalization circuit is controlled by a specific region in the brainstem that regulates breathing rhythms, thereby ensuring that the act of breathing remains the dominant function over speech production.
According to Fan Wang, a professor at MIT and the senior author of the study, "When you need to breathe in, you have to stop vocalization. We found that the neurons that control vocalization receive direct inhibitory input from the breathing rhythm generator." This mechanism highlights the intricate coordination between breathing and speaking processes within the brain.
The lead author of the study, Jaehong Park, along with a team of researchers, utilized a mouse model to investigate how the brain oversees vocalization. Mice produce ultrasonic vocalizations (USVs) by exhaling air through nearly closed vocal cords, creating a distinct whistling mechanism for communication. By studying the neural circuits involved in vocal cord adduction, the researchers identified a group of premotor neurons in the hindbrain region known as the retroambiguus nucleus (RAm) that play a critical role in vocalization.
The researchers discovered that these RAm neurons were highly active during USVs, leading them to identify vocalization-specific neurons within the RAm, termed RAmVOC. Through chemogenetics and optogenetics techniques, the team demonstrated that silencing or stimulating the activity of these neurons directly impacted the mice's ability to vocalize. When RAmVOC neurons were blocked, the mice could not produce any vocalizations, indicating the essential role of these neurons in controlling vocalization.
Furthermore, the researchers found that neurons in the pre-Bötzinger complex of the brainstem, responsible for generating inhalation rhythms, inhibit the activity of RAmVOC neurons. This inhibition ensures that breathing takes precedence over vocalization, emphasizing the importance of pausing speech to accommodate the need for breathing.
While the study was conducted in mice, the researchers believe that the identified brain circuit may play a similar role in speech production and breathing in humans. Despite the complexity of human speech, the fundamental processes of vocalization, such as vocal cord closure and air exhalation, are shared between humans and mice.
Moving forward, the researchers aim to explore how other functions, such as coughing and swallowing, may be influenced by the intricate brain circuits that regulate breathing and vocalization. This groundbreaking research opens new avenues for understanding the fundamental mechanisms underlying the coordination of speaking and breathing in both mice and humans.
(Source: https://www.eurekalert.org/news-releases/1036410)
The newly discovered circuit is crucial for two essential components of vocalization: the narrowing of the larynx and the exhalation of air from the lungs. It was found that this vocalization circuit is controlled by a specific region in the brainstem that regulates breathing rhythms, thereby ensuring that the act of breathing remains the dominant function over speech production.
According to Fan Wang, a professor at MIT and the senior author of the study, "When you need to breathe in, you have to stop vocalization. We found that the neurons that control vocalization receive direct inhibitory input from the breathing rhythm generator." This mechanism highlights the intricate coordination between breathing and speaking processes within the brain.
The lead author of the study, Jaehong Park, along with a team of researchers, utilized a mouse model to investigate how the brain oversees vocalization. Mice produce ultrasonic vocalizations (USVs) by exhaling air through nearly closed vocal cords, creating a distinct whistling mechanism for communication. By studying the neural circuits involved in vocal cord adduction, the researchers identified a group of premotor neurons in the hindbrain region known as the retroambiguus nucleus (RAm) that play a critical role in vocalization.
The researchers discovered that these RAm neurons were highly active during USVs, leading them to identify vocalization-specific neurons within the RAm, termed RAmVOC. Through chemogenetics and optogenetics techniques, the team demonstrated that silencing or stimulating the activity of these neurons directly impacted the mice's ability to vocalize. When RAmVOC neurons were blocked, the mice could not produce any vocalizations, indicating the essential role of these neurons in controlling vocalization.
Furthermore, the researchers found that neurons in the pre-Bötzinger complex of the brainstem, responsible for generating inhalation rhythms, inhibit the activity of RAmVOC neurons. This inhibition ensures that breathing takes precedence over vocalization, emphasizing the importance of pausing speech to accommodate the need for breathing.
While the study was conducted in mice, the researchers believe that the identified brain circuit may play a similar role in speech production and breathing in humans. Despite the complexity of human speech, the fundamental processes of vocalization, such as vocal cord closure and air exhalation, are shared between humans and mice.
Moving forward, the researchers aim to explore how other functions, such as coughing and swallowing, may be influenced by the intricate brain circuits that regulate breathing and vocalization. This groundbreaking research opens new avenues for understanding the fundamental mechanisms underlying the coordination of speaking and breathing in both mice and humans.
(Source: https://www.eurekalert.org/news-releases/1036410)
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