Please don't link io9 for scientific articles -- their science journalism is generally subpar, often barely more than crudely summarizing abstracts in Nature or Science.
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.
I don't think people are generally aware of how awful io9 is, or any of the other science news out there. Even worse is that most science news is pump-and-forget. I don't know how to fix that, or make more people aware in a useful way. Give me the paper or give me death!
It is widely accepted that hippocampal replay occurs during sleep and is an important part of memory consolidation.
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.
This line, fairly early in the article, sounds like BS. If not BS, then it is poor writing, because it hand-waves over a huge chasm:
"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!
Maybe it's the rats who are experimenting on us, faking hippocampal replay responses to control the dreams of neuroscientist "researchers", making them run through cognitive mazes while drooling after the ephemeral crumbs of peer accolades and citation cred...
I would like to know more info about how they know what the rats are dreaming about. It sounded like they knew with a high degree of confidence that the rats were dreaming about something. I want to know they knew this.
One way I know this is possible, from prior research, is by implanting electrodes into the rat's hippocampi to detect activation in the place cells.
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.
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.
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.