Researchers accomplished the incredible feat of implanting memories into mice while they were asleep.
Researchers from the French National Center for Scientific Research (CNRS) and their colleagues announced that following the procedure, the rodents were able to recall the artificial memories, The Scientist reported. The findings highlight a causal role between the firing of specific neurons and the ability of these neurons to represent a particular place in space.
"This was a fantastic, well-thought-out idea that, miraculously, worked," said neuroscientist György Buzsáki of the New York University Neuroscience Institute who was not involved with the work, The Scientist reported. "The study shows that the emotional value of a particular [location] can be modified, and, what is most critical, is that this can happen in a subconscious, sleep state."
To create these false memories the researchers identified a single place cell (firing neuron) in the hippocampus that was activated when an individual mouse was in a specific location. When that place cell became active during a waking or sleep state the team imposed an automatic stimulation of the medial forebrain bundle (which is responsible for reward sensations) using a brain-computer interface.
The researchers found once the reward illusion was created, the mice spent five times more time in the location associated with the stimulated place cell than they had before. When the stimulation occurred during sleep, the mice were more likely to go directly to the associated location upon waking.
"The animal developed a goal-directed strategy for the [location], as if the animal had a conscious recollection that there was a reward there," said Karim Benchenane, a neuroscience researcher at CNRS and ESPCI-ParisTech, The Scientist reported.
The findings also provide evidence that the activity of place cells during sleep provide the same spatial information as they do during an awake state.
The findings were published in a recent edition of the journal Nature Neuroscience.
