Breakthrough discovery could lead to new treatments for sleep disorders
In a major breakthrough in sleep research, a team of scientists has identified the neural control center for rapid eye movement (REM) sleep. The discovery, made through experiments on mice, saw researchers inducing REM sleep by stimulating a specific circuit at the top of the brainstem. The findings could potentially deepen our understanding of human sleep biology and its disorders.
Potential applications in treating sleep disorders
The team's findings could have major implications in treating sleep disorders like sleep apnea, narcolepsy, and REM disorders. These conditions often involve distressing nightmares or physical manifestations of dreams through movement or vocalizations. The newfound knowledge about the brain's control center for REM sleep, could potentially be used to manipulate this stage of sleep in patients suffering from these disorders.
Unraveling the mysteries of REM sleep
The precise location and role of the brain's REM sleep control center have long been debated among scientists. Some researchers have proposed that neurons in the mammalian brainstem are key to triggering REM sleep. This theory stems from observations in cats, where removal or damage to the brainstem prevents proper REM sleep and leads to dream enactment behaviors.
Brainstem's role in REM sleep and related disorders
Similar dream enactment behaviors have been seen in humans with known brainstem degeneration (like in Parkinson's disease). This further supports the theory of the brainstem's role in REM sleep. The pons, at the top of the brainstem, has been identified as a potential 'control center' for muscle relaxation during REM sleep through rodent studies. However, identifying specific pathways responsible for this crucial phase has proved challenging due to intermingling neurons promoting wakefulness and sleep.
Discovery of REM-related neurons in the brainstem
Neuroscientist Mitsuaki Kashiwagi and his team have pinpointed a cluster of REM-related neurons in the dorsal region of the pons. These neurons, called Crhbp+ neurons due to their expression of a corticotropin-releasing hormone-binding protein, project from the pons to Nos1+ neurons in the medulla oblongata. This loop could potentially act as a core circuit for REM sleep, Kashiwagi and his colleagues said.
Manipulation of pons neurons affects REM sleep
The team's experiments revealed that when pons neurons were taken out of the loop, mice had less sleep and impaired muscle relaxation during REM sleep. On the other hand, activating these neurons increased the number and duration of REM episodes at the cost of wakefulness. This indicates that manipulating these neurons could potentially be used as a therapeutic strategy for sleep disorders.
