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Memories• New experiences 'improve memory' • Sleep loss 'harms route memory' • Old age is 'no bar to sharp mind' Being exposed to new experiences can boost memory, research suggests. UK scientists believe introducing new facts when learning, rather than repeatedly processing information, improves memory performance. They have discovered that a region of the brain associated with a chemical important for the long-term memory is activated by novelty. The team says their findings, published in the journal Neuron, may potentially help the treatment of memory problems. Scientists from University College London (UCL) scanned volunteers' brains using magnetic resonance imaging (MRI) while showing them both new images and images they had already seen. They discovered the novel images activated a region of the brain called the substantia nigra/ventral tegmental, while the familiar images did not. This region of the brain is associated with motivation and reward-orientated behaviours. It is also responsible for regulating a chemical called dopamine, a neurotransmitter that aids memory formation in the brain. Lead researcher Dr Emrah Duzel, from the Institute of Cognitive Neuroscience, UCL, said: "We wanted to find out why our brain is so affected by new experiences and new information. "We thought novelty might be an incentive - something that has reward properties. "We found that a brain area that we know codes for reward was also responsive to novelty." New learning methods The team believes this means humans could be attracted to new information - and that this brain activation could in turn have an impact on dopamine levels, and therefore memory. They say these findings may have an impact on the treatment of memory problems. Dr Duzel said: "Current practice by behavioural psychologists aims to improve memory through repeatedly exposing a person to information - just as we do when we revise for an exam. This study shows that revising is more effective if you mix new facts in with the old". "You actually learn better, even though your brain is also tied up with new information." Professor Keith Kendrick, head of cognitive and behavioural neuroscience at the Babraham Institute, UK, said: "It is a lovely idea, in principle, that perhaps you could use this to help people with learning difficulties to recall information by introducing new information into the tasks you are doing". He added: "The other aspect of this study is that we have evolved to find novelty exciting. All species are attracted - and repelled - by novelty. If you do not explore you don't progress." Losing sleep can interfere with the part of the brain responsible for finding your way round, a study says. US researchers found rats that were deprived of sleep had difficulty navigating a maze. Restricting sleep interfered with the rats' spatial memory - responsible for recording information about the surrounding environment, the team said. But UK experts were divided over the findings published in the Journal of Neurophysiology. Spatial memory is essential for rats and humans to remember familiar environments, people use it to find their way round a city, while it is used by rats in hunting for food. The team took two groups of rats, putting one in a water maze where they could not see or smell the exit. The rats were repeatedly put in the maze again once they had slept with some being allowed to sleep for six hours longer than others. Researchers found the rats which had more sleep produced more cells in the hippocampus part of the brain, which is responsible for spatial learning as it is in humans, and were better at finding their way out. The second group were also put in a maze, but were allowed to see and smell the exit - the door was scented with citrus - which was moved every fourth trial. Senses In this group, the sleep deprived rats performed better. The researchers said this was unexpected and suggested the sleep deprived rats were quicker to use their senses because their spatial learning was impaired. Lead researcher Ilana Hairston said as well as proving sleep deprivation affected spatial memory, the suggestion was that sleep did not affect senses. "This may be significant in human learning as well and implies that it may be possible to optimise the way information ins presented to rested versus fatigued individuals to take advantage of the specific neural substrates that are unaffected by sleep loss." She added this could specifically help medical and military training and further research could be carried out to see if sleep loss affected other brain and memory functions in a similar way. But UK experts remained mixed over whether sleep affected spatial learning. Professor Jim Horne, director of the Loughborough Sleep Research Centre, said it would be wrong to assume rats and humans would react in similar ways. And he added: "I don't believe spatial learning is harmed by sleep deprivation. Research has suggested that it depends what task people are asked to do. If it is boring, sleepy people just switch off, but don't do the same for exciting tasks." However, Dr Neil Stanley, of the University of Surrey, said sleep loss harmed spatial learning, although the brain could rise to the "spatial learning" challenge in the short-term it would struggle eventually. Being older is no bar to having a razor sharp mind - but it may well work in a different way, US scientists suggest. A Johns Hopkins University team, who studied rats, found older animals stored memories in a different way than younger ones. They say that, if the findings are true for humans, it could lead to treatments to prevent memory loss which were tailored to older brains. The research is published in Nature Neuroscience. Old v young The researchers compared the brains of six-month-old "young" rats with those of two-year-olds "old" rats, who were deemed to be relatively sharp because they had performed well in various learning tasks. These rats' brains were also compared with those of older rats which had showed declines in their abilities to learn new things. The researchers looked at a key set of nerve cell connections that store information by modifying the strength of chemical communications at synapses - the tiny gaps between nerve cells, where chemicals released by one cell act upon another. Synaptic communication is the way brains register and preserve information to form memories. The team found that while the older rats that were less able to learn new things had brains that had lost the ability to adjust the force of those synaptic communications, the sharper older rats still had that capacity. And the successful older rats also relied far less than did younger rats on a synaptic receptor that is linked to a common mechanism for storing memories. Drug target Dr Michela Gallagher, who worked on the study, said: "We found that aged rats with preserved cognitive abilities are not biologically equivalent to young rats in some of the basic machinery that neurons use to encode and store information in the brain. Instead, successful agers relied more than young rats on a different mechanism for bringing about synaptic change. "This 'switch' could serve the same purpose - storing memories - but through a different neurochemical device. Professor Shane O'Mara, of the Institute of Neuroscience, at Trinity College Dublin, said: "This is a fascinating paper that seeks to address a difficult but important question. Why are some people mentally productive until late old age - such as the philosopher Bertrand Russell, and why do others not show this resilience - such as the writer Iris Murdoch?" "Modern brain imaging shows that there are differences between the brains of those who age 'successfully' compared to the brains of young people". Professor O'Mara added: "This study suggests that there is a difference in the regulation of a key biochemical messenger in the brain. "If these findings prove to be generally applicable, then they show that the resistance to mental ageing shown by some people has a biochemical basis, and they point to what this biochemical basis is. "In turn, this suggests a target for drugs to rescue or reduce the effect of ageing on brain function and hence on cognitive or memory function with ageing." See also Memories are made of... Improving reading skills and comprehension Memory and memory loss Untangling the Web of Alzheimer's Disease Some strategies to reduce your reading time Australian research shows mobile phones affect brain function |
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