A lack of sleep can cause parts of the brain's synapses to be 'eaten' by other brain cells, according to a new study by researchers at the Marche Polytechnic University in Italy.

Astrocytes are a cell in the brain that clean out worn-out cells and debris. Scientists studying the brains of mice found these cells were more active when the animals had been deprived of sleep, breaking down more of the brain's connections.

“We show for the first time that portions of synapses are literally eaten by astrocytes because of sleep loss,” research leader Michele Bellesi told New Scientist.

However, that's not necessarily a bad thing, as most of the synapses affected were larger and more mature: “They are like old pieces of furniture, and so probably need more attention and cleaning,” said Bellesi.

A more worrying finding was that 'microglial' brain cells, which seek out damaged cells and debris, were also more active in brain experiencing chronic sleep deprivation.

“We already know that sustained microglial activation has been observed in Alzheimer’s and other forms of neurodegeneration,” Bellesi said.

Previous research has found that chronic sleep deprivation increases so-called plaques in the brain thought to be a main cause of Alzheimer’s and other dementias.