From the perspective of your brain, dreaming and movie-watching are strangely parallel experiences. In fact, one could argue that sitting in a darkened theater and staring at a thriller is the closest one can get to REM sleep with open eyes.
Consider this study, led by Uri Hasson and Rafael Malach at Hebrew University: they showed subjects a vintage Clint Eastwood movie (“The Good, The Bad and the Ugly”) and watched what happened to the cortex in a scanner. The scientists found that when adults were watching the film their brains showed a peculiar pattern of activity, which was virtually universal. In particular, people showed a remarkable level of similarity when it came to the activation of areas including the visual cortex (no surprise there), fusiform gyrus (it was turned on when the camera zoomed in on a face), areas related to the processing of touch (they were activated during scenes involving physical contact) and so on.
—The Neuroscience of Inception | Wired.com (via kenyatta)