Real-life technologies can perform some of the mind-reading tricks shown in the new film Inception, in which people are able to observe and participate in someone’s dreams.

Jack Gallant, a neuroscientist at the University of California, Berkeley shows people images and movies while taking a functional magnetic resonance imaging (fMRI) scan of their brains. He uses brain-pattern analysis and computer algorithms to analyze the fMRI scans and build a model of the subject’s visual system. Using the model, Gallant can then have his subject watch a completely new movie and then he can reproduce the images the subject has seen in that new movie with very good accuracy. Gallant says he can use the same technology to reproduce images of the dreams from a person’s brain.

Advanced Telecommunications Research (ATR) Computational Neuroscience Laboratories also takes fMRI scans of what the subject sees. Instead of building a model of the visual system, ATR feeds fMRI scans into a computer, which “learns” how to associate changes in brain activity with different images. Lab scientists can reconstruct simple black-and-white images the subject is viewing by analyzing the blood flow in the brain’s visual cortex. ATR says reconstructing dreams is harder because the brain signals during sleep may be “noisier,” and is now researching how to get more meaningful information from a sleeper’s brain.

Modifying dreams is not technically feasible at this time.