Chinese scientists have developed a new method to reactivate pleasant memories to weaken negative ones while you sleep.
- Chinese researchers asked people to associate 48 random words with no particular meaning with a list of negative and then positive images.
- When audio recordings of words spoken aloud were played during REM sleep, recall of traumatic memories became weaker and involuntary intrusions of positive memories increased.
- Furthermore, reactivation of good memories enhanced positive affective judgments after sleep.
Remembering painful or traumatic experiences can be deeply troubling. Previous research has suggested that sleep may offer the possibility of reducing this suffering and more specifically of reactivating good memories. To find out, researchers from the University of Hong Kong (China) introduced a memory editing procedure aimed at weakening negative flashbacks by reactivating more recent positive memories during REM sleep. This is a “period during which brain activity is close to that of the waking phase”according to Inserm. The latter, also called REM (Rapid Eye Movement) period due to frequent rapid eye movements (under closed eyelids), is conducive to dreams, especially those that can be remembered once awake.
48 meaningless words associated with negative and positive images
As part of the intervention, 37 people associated 48 random words with no particular meaning with a list of so-called “negative” images, such as injuries or dangerous animals. Then they slept. The following evening, the participants made connections between half of the words previously learned and positive images (smiling children, beautiful landscapes, etc.), thus creating interference. During sleep, with rapid eye movements, audio recordings of words spoken aloud were played to consolidate memory. Subsequently, the brain activity of the volunteers was examined using an electroencephalogram.
Non-invasive sleep intervention modifies bad memories and affective responses
According to the results, published in the journal Proceedings of the National Academy of Sciences (PNAS)presentation of cues associated with negative and positive images during sleep, as opposed to no cues, weakened recall of bad memories while increasing intrusions of positive memories. “Supporting these memory benefits, modeling revealed that playing the audio recordings facilitated the accumulation of evidence in favor of positive affect judgments. Additionally, theta brain rhythms elicited by the audio recordings during REM sleep predominantly predicted recall of positive memories.”
According to the authors, this procedure could help treat mental disorders linked to traumatic memories, such as post-traumatic stress syndrome, anxiety and depression.
