Stories prepare our minds for what is to come. Dreams are a sort of training process for the development and consolidation of neural architecture.

While deep sleep is characterised by low brain activity, brain activity is high during REM sleep, similar to wakefulness. If we wake up in REM sleep, it is very common for us to remember that we were dreaming. But why do we dream? Ferran Martinez-Garcia explains.

Question sent by TERESA OLIVER (Alcoi). EDUARD ESTIVILL and NURIA ROURE answer: Sleep and waking life are brain functions and are thus subject to changes of the nervous system. Sleep is neither a passive situation nor a lack of wakefulness, but an active state during which changes