Saturday 26 December 2015

Sleep isn’t needed to create long-term memories – just time out


Need to remember something important? Take a break. A proper one – no TV or flicking through your phone messages. It seems that resting in a quiet room for 10 minutes without stimulation can boost our ability to remember new information.
The effect is particularly strong in people with amnesia, suggesting that they may not have lost the ability to form new memories after all.
“A lot of people think the brain is a muscle that needs to be continually stimulated, but perhaps that’s not the best way,” says Michaela Dewar at Heriot-Watt University in Edinburgh, UK.
Memory boost
New memories are fragile. They need to be consolidated before being committed to long-term storage, a process thought to happen while we sleep. But at least some consolidation may occur while we’re awake, says Dewar – all you need is a timeout.
In 2012, Dewar’s team showed that having a rest helps a person to remember what they were told a few minutes earlier. And the effect seems to last. People who had a 10-minute rest after hearing a story remembered 10 per cent more of it a week later than those who played a spot-the-difference game immediately afterwards.
“We dim the lights and ask them to sit in an empty, quiet room, with no mobile phones,” says Dewar. When asked what they had been thinking about afterwards, most volunteers said they had let their minds wander.
Now Dewar, along with Michael Craig at the University of Edinburgh and their colleagues, have found that spatial memories can also be consolidated when we rest.
Volunteers who rested after exploring a virtual-reality environment were 10 per cent more accurate at orientating themselves in relation to virtual landmarks than those who played a game of spot the difference afterwards.
It’s good to rest
These findings together suggest that simply resting while we’re awake can give us some of the memory benefits thought to be confined to sleep.
This is good news for insomniacs. “As long as you’re reasonably relaxed, you might still be experiencing some of the memory-consolidation processes that sleep would normally do,” says Gareth Gaskell at the University of York in the UK.
The research could have bigger implications for people with amnesia. When Dewar’s team conducted a memory experiment with people who had the condition, they saw more striking results. “Most of them can’t lead a normal life because they can’t remember what they did 10 minutes ago,” she says – but all showed huge improvements on the memory test when given a break.
The volunteers were able to recall between 30 and 80 per cent of a list of words when they rested for 9 minutes. Without a break, eight of the 12 were unable to remember anything.
“The findings challenge current theories of memory,” says Dewar. “It is typically assumed that people with amnesia lose the ability to consolidate memories; they can take in information but it is rapidly gone.”
Information overload
Dewar thinks that overstimulation may be what causes memory problems in people with amnesia. “If we try to reduce the amount of information going in, people with amnesia can form new memories. There is some spare capacity there that we can tap into,” she says.
“It is very surprising and exciting,” says Gaskell. “If we can understand how this takes place, we could help people with amnesia,” he says.
Dewar hopes to investigate whether having plenty of breaks can help people with amnesia to learn new information, such as family news or how to navigate a new home. She has reason to be optimistic: the wife of a man with Alzheimer’s who took part in her study says she has used the technique to teach her husband the name of his new grandchild.


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