Researchers at the University of Buffalo and Harvard have located what they call a “sleep-promoting circuit located deep in the primitive brainstem” that regulates deep sleep. According to the article titled “The GABAergic parafacial zone is a medullary slow wave sleep–promoting center”, this is only the second “sleep node” identified in the mammalian brain.
Published online in Nature Neuroscience, the study demonstrates that fully half of all of the brain’s sleep-promoting activity originates from the parafacial zone (PZ) in the brainstem. The brainstem is a primordial part of the brain that regulates basic functions necessary for survival, such as breathing, blood pressure, heart rate and body temperature. Click Here for Article Preview
“The close association of a sleep center with other regions that are critical for life highlights the evolutionary importance of sleep in the brain,” says Caroline E. Bass, assistant professor of Pharmacology and Toxicology in the UB School of Medicine and Biomedical Sciences and a co-author on the paper.
The researchers reportedly found that a specific type of neuron in the PZ that makes the neurotransmitter gamma-aminobutyric acid (GABA) is responsible for deep sleep. They used a set of innovative tools to precisely control these neurons remotely, in essence giving them the ability to turn the neurons on and off at will.
“These new molecular approaches allow unprecedented control over brain function at the cellular level,” says Christelle Ancelet (in Science Daily), postdoctoral fellow at Harvard School of Medicine. “Before these tools were developed, we often used ‘electrical stimulation’ to activate a region, but the problem is that doing so stimulates everything the electrode touches and even surrounding areas it didn’t. It was a sledgehammer approach, when what we needed was a scalpel.”
“To get the precision required for these experiments, we introduced a virus into the PZ that expressed a ‘designer’ receptor on GABA neurons only but didn’t otherwise alter brain function,” explains Patrick Fuller, assistant professor at Harvard and senior author on the paper. “When we turned on the GABA neurons in the PZ, the animals quickly fell into a deep sleep without the use of sedatives or sleep aids.”