Manipulating memories perhaps sounds too good to be true. But, scientists from the National Center for Scientific Research (CRNS) in France have succeeded in tampling with those of sleeping mice by inserting false cheerful memories using electrode stimulation.
The findings have been published in the journal Nature Neuroscience.
The team of researchers created positive feelings relating to a specific location the five mice used as subjects had visited earlier on the same day.
The brains of the mice were stimulated while they slept oblivious of what was being done to them.
When they woke up, it was observed that the stimulated feelings were so strong that they returned to that particular location, probably trying to seek rewards.
“The mouse develops a goal-directed behaviour to go towards the place,” lead author Karim Benchenane said in a statement. “It proves that it’s not an automatic behaviour. What we create is an association between a particular place and a reward that can be consciously accessed by the mouse.”
The scientists first located specific neurones in the brains of the mice along which signals relating to spatial memories of specific locations travel.
They then incorporated electrodes into the hippocampus of the mice, which is the region of the brain involved in memory formation.
The neural activity was recorded with electrodes as the mice explored that particular location.
The subjects were monitored when they slept for an hour. When the neurones initially identified began firing, the researchers concluded that the mice were recalling their activities of the day. Every time these cells fired, the scientists used a different electrode to stimulate that region of the brain associated with pleasure, thereby linking the experience of the day with stimulated good feelings such that the mice returned to that spot when they woke up because of the new memory that was created, making them recall (falsely so) that location as to having rewards.
The authors hope that their findings are applied in real-life situations to humans.
Benchenane spoke of their goal as follows:
“The idea is to use this as a tool for post-traumatic stress disorder.”
Another scientist not involved in the study, Loren Frank, a neuroscientist from the University of California, commented on the findings:
“I think this is a really important step towards helping people with memory impairments or depression. In principle, you could selectively change brain processing during sleep to soften memories or change their emotional content.”