Neuroscientists successfully control the dreams of rats
io9.com
io9.com
In this case they cite the wrong primary author -- attributing the work to Matt Wilson instead of Daniel Bendor. While Matt Wilson is the sponsoring author (ie providing the facilities and general supervision), this is Dr. Bendor's experiment and he is entirely uncredited here.
It is not widely accepted that this activation is, or even leads to, the subjective experience that we call dreaming.
The article gets it right in the second paragraph, but most of the rest of the paper makes incorrect reference to dreams. Don't expect to program your dreams any time soon.
The actual result here is very interesting in its own right; it suggests that the consolidation process can be directed, and if the replay system plays the role in learning that many people suspect it does, then we might be able to focus our learning on particular experiences. The idea of learning something while you sleep by playing a tape might not be as ridiculous as I always thought it was.
"Using correlative analysis, Wilson confirmed that the rats were dreaming of their maze navigating exploits from the day before."
They absolutely confirmed the rats were dreaming specifically of the mazes of the day before, by analyzing their neural activity? If so, that technology is FAR more interesting than merely controlling their dreams!
In a nutshell, place cells are cells in the hippocampus that are associated with particular regions of the environment (their 'place field'). They activate when the animal visits a place, thinks about a place or, critically, dreams about a place. The theory is that they're used by your hippocampus to tie together memories gathered in a particular place during memory consolidation, to help you recall details about a familiar environment, and to help build navigation maps of the environment (by linking place cells' fields together where their fields are close or overlap).
In one study I read a few years ago, neuroscientists implanted electrodes into a rat's brain and had them run the maze repeatedly, tracking where they were in the maze and what cells were activated. Later, when the rats were asleep, they recorded the activation again, and found that they activated in the same sequence that they did when the rats were actually in the maze. This strongly implies that they were dreaming about running the maze.
This study seems to be an extension of that where they showed they could direct the sleeping rats through the maze with 'turn left' and 'turn right' cues the rats learned while awake.
http://en.wikipedia.org/wiki/Place_cell
Edit: To be clear, the hypothesis that this replay happens because the rats are dreaming is pure speculation. My personal hunch is that's what's going on, but that's all it is: a hunch, an assumption. There's no way to be sure whether they are experiencing what we call 'dreaming'. All we know is that the place cells in the rats' hippocampi 'replays' the place cell activation in the same order that they activated while awake.
It's pretty widely accepted that during sleep, the hippocampus replays patterns of activation that were produced during the day. In this case, that means that the rats are essentially traversing the maze in their sleep.
However, this is _not_ dreaming. The neural replay activity is seen in humans and animals alike, but it doesn't correspond to the subjective experience of dreaming in humans, AFAIK.