Nap 'boosts' brain learning power according to article on BBC news.

"Sleep not only rights the wrong of prolonged wakefulness, but, at a neurocognitive level, it moves you beyond where you were before you took a nap" according to Dr Matthew Walker,at UC Berkeley.

I found this post on BBC news " The latest study, from the University of California at Berkeley, suggests that the brain may need sleep to process short-term memories, creating "space" for new facts to be learned. " http://news.bbc.co.uk/2/hi/health/8524549.stm

The quality of sleep at night as well as during naps determine how successfully are brains function cognitively and in terms of short term memory.

According to the BBC news "Dr Matthew Walker, who led the study, reported at the AAAS conference in San Diego, said: "Sleep not only rights the wrong of prolonged wakefulness, but, at a neurocognitive level, it moves you beyond where you were before you took a nap.
"It's as though the e-mail inbox in your hippocampus is full, and, until you sleep and clear out all those fact e-mails, you're not going to receive any more mail.
"It's just going to bounce until you sleep and move it into another folder."
However, Professor Derk-Jan Dijk, the director of the Surrey Sleep Research Centre, said that there was no clear evidence that daytime napping offered a distinct advantage over sleeping just once over 24 hours.
"The sleep-wake cycle is not as rigid as we might think - we have the capability to sleep in different ways."
He said that while the brain effect reported in the study might be spotted in a laboratory setting, the picture became more clouded in the "real world".
"The size of these effects are much more difficult to assess - if I have to learn something, for example, it's easier to do this when I'm feeling awake and alert than when I'm sleepy.""

I will try to read original studies and post again.

Dr Shapira