All-night revision for exam? Sleep on it
New Delhi, 29 April 2012: Staying up all night to revise your exam syllabus just one more time might not be a great idea after all. Far from brushing up your memory, it might lead you to forget most of what you learned.
Recent research by the School of Life Sciences(SLS) in Jawaharlal Nehru University has revealed that sleep plays a significant role in encoding information and retaining what is learned through the day. So after a day of cramming, if you are sleep-deprived, chances are you will remember very little. The research team led by Dr Sushil Jha found that rats deprived of sleep for six hours just after learning a task couldn’t perform the same task well the next day while the other group that got adequate sleep replicated it.
The laboratory is now working on establishing that learning, in turn, changes sleep pattern. "Yes, if you have gone through any kind of training or learning, you may sleep more. This is not because you are tired but because memory consolidation needs proper sleep. Sleep also activates the brain’s protein synthesis machinery which helps consolidate memory. Further, sleep helps in brain development, which is why babies sleep more," said Jha, assistant professor of neuroscience at SLS.
He added that this was the first time in India that research showed sleep deprivation impaired trace-learning in rats.
One of the studies by the team, on impairment of memory due to sleep deprivation, was published in Elsevier journal. "We used male Wistar rats that were taught a task using a paired stimulus of fruit juice and light. Juice was always given after presenting light as a cue to them in their chamber. While all the rats were taught these cues, one group of rats was not allowed to sleep for six hours after learning and the other was allowed to sleep. Next morning, when we gave the cues again, the sleep-deprived rats showed an impaired performance. They poked the juice 45.72% less than the non-sleep deprived group," said Jha.
Recent research from the University of Notre Dame also shows that going to sleep shortly after learning new material is most beneficial for recall. The study was performed with 207 students and concluded that recall was best when students slept for sometime right after lessons.
"If a person is stressed then the retrieval phenomenon of memories is also impaired. The health of the person is also compromised if he/she does not get proper sleep. That is why most people who are sleep deprived also tend to suffer from hypertension, diabetes, obesity and insomnia. These health conditions are related," he added.
Another recent study by the group published in ’Frontiers in Neurology’ looks at the function of rapid eye m(REM) sleep state in maintaining a long spell of sleep. The study suggests that when one is in deep sleep (non-REM sleep), breathing rate goes down and that is why CO2 level increases in the body. REM sleep eliminates excess CO2 from the body and helps maintain uninterrupted sleep.