SCIENCE IN THE MOVIES
Inception considered, among others, several technological developments of future science: shared dreams, the ability to implant and extract information from a sleeping mind and the technology to sedate the brain in order to obtain a more stable sleep.
It is difficult to judge its scientific feasibility because we are far away from understanding dreams, so there are only models that claim to explain dreaming, but not something as scientifically accepted as organic evolution or relativity in physics.
Crick and Mitchison's old model, based on the idea that only higher mammals dream, stated that dreaming is the way the brain stores useless memories and leaves only important memories within easy reach.
Kavanau's model, recently proposed that any vertebrate that receives many daily images needs to dream to clear up the memory, and this model is based on the existence of blind fish that apparently do not dream.
On a human level, it has been found that women, who may feel less secure in this sexist society, have more nightmares than men, and both sexes recall nightmares better than pleasant dreams. These emotions' effect over dreams suggests that, at least for us, the dreams put the day's experiences within the context of our lives and help overcome fears, according to the Hartmann model.
But regardless of the model, dreams have physical existence in our brains, in the form of molecules and electrical impulses. We can imagine a neuron scanner that could read each molecule and pass the information to a computer, opening the possibility of extracting information from a sleeping mind and even to achieve immortality, because our mind with its personality and memories could be implanted in a new body if the current body dies. For now, no technology allows this.
The only existing capability shown in the movie is that the brain can be chemically influenced to obtain a more stable sleep. Unfortunately, for people like Michael Jackson, such technology proved lethal.