Yes I've seen that episode of Dexter's laboratory too.
(I do not own the video clip above)
From Smithsonian Mag:
The average American sleeps some 7.6 hours a night—maybe
not as much as one would like, but a number that still amounts to more
200,000 hours total over the course of a lifetime. What if there were
some way to use all these hours to do something we don’t have the time
to do while awake, like learn to play a musical instrument or speak a
The idea that you can learn new things through some sort of magical
mental osmosis while you sleep has long been wishful thinking. But a new study by Northwestern University researchers indicates
that, depending on what we hear during the night, it is indeed possible
to reinforce existing memories and enhance our recall after we wake up.
Click the source links below for more.
Sources -> http://gizmodo.com/5921668/how-to-keep-learning-even-when-youre-asleep via http://www.nature.com/neuro/journal/vaop/ncurrent/full/nn.3152.html#/author-information & http://blogs.smithsonianmag.com/science/2012/06/experiments-show-we-really-can-learn-while-we-sleep/