A primitive part of the brain harbours a region that controls sleep, researchers have found.

According to researchers at the Harvard School of Medicine and the University at Buffalo School of Medicine and Biomedical Sciences, parafacial zone (PZ) in the brainstem controls sleep in mammals. The brainstem is the most primitive part of the brain and regulates several functions such as breathing, heart rate, blood pressure.

"The close association of a sleep center with other regions that are critical for life highlights the evolutionary importance of sleep in the brain," said Caroline E. Bass, assistant professor of Pharmacology and Toxicology in the UB School of Medicine and Biomedical Sciences and a co-author of the study.

The team found that neurons that make the neurotransmitter gamma-aminobutyric acid (GABA) are behind deep sleep. The researchers even demonstrated that, using specific equipment, these neurons can be switched on and off at will.

"These new molecular approaches allow unprecedented control over brain function at the cellular level," said Christelle Ancelet, postdoctoral fellow at Harvard School of Medicine, according to a news release. "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."

In the study, the researchers sent a virus to PZ that expressed a designer receptor on GABA neurons. The virus did not alter any other brain functions. According to the researchers, when they switched on GABA neurons in PZ, the animal models fell into a deep sleep. No sedatives or sleep aids were used in the research.

The study is published in the journal Nature Neuroscience.             

Recently, scientists at Beth Israel Deaconess Medical Center in Boston, had found that old people often start to sleep less due to loss of a particular set of neurons called ventrolateral preoptic neurons.