NEW YORK, Jan 13: Scientists have discovered a promising new approach to potentially treating a variety of mental health issues by weakening negative memories. This method involves reactivating positive memories to help erase bad memories and traumatic flashbacks.

In a study conducted over several days, an international team of researchers asked 37 participants to associate random words with negative images. Then, half of these associations were "reprogrammed" to interfere with the bad memories. "We found that this procedure weakened the recall of aversive memories and also increased involuntary intrusions of positive memories," the researchers wrote in their published paper.

For the experiment, the team used recognized image databases that categorized images as either negative (such as human injuries or dangerous animals) or positive (such as calm landscapes and smiling children). On the first evening, memory training exercises were used to link negative images with nonsense words specifically created for the study. The following day, after a night’s sleep that helped consolidate those memories, the researchers attempted to associate half of the words with positive images in the participants' minds.

During the second night of sleep, the researchers played recordings of the nonsense words while participants were in the non-rapid eye movement (NREM) sleep phase, which is known to play a key role in memory storage. Brain activity was monitored using electroencephalography, and a significant spike in theta-band activity, which is linked to emotional memory processing, was observed in response to the audio cues. This activity was notably higher when positive cues were used.

Afterward, participants completed questionnaires the following day and several days later. The results showed that participants were less able to recall the negative memories that had been paired with positive images. Instead, positive memories were more likely to surface, with participants viewing them with a more positive emotional bias.

"A noninvasive sleep intervention can thus modify aversive recollection and affective responses," the researchers wrote. "Overall, our findings may offer new insights relevant for the treatment of pathological or trauma-related remembering."

While the research holds promise, it is still in its early stages. It's important to note that this was a controlled lab experiment, which ensures the accuracy of the results but may not fully reflect real-world memory formation. The researchers pointed out that seeing aversive images in a lab setting might not have the same impact on memory formation as experiencing a traumatic event, which could be harder to overwrite.

Previous studies have shown that the brain replays memories briefly during sleep, and many have explored how this process might be controlled to strengthen positive memories or erase negative ones. However, with so many variables in play—including the types of memories, brain areas, and sleep phases involved—it will take time to determine exactly how memory editing could work and how long-lasting the effects might be. Despite these challenges, the process of overwriting negative memories with positive ones shows considerable promise.

"Our findings open broad avenues for seeking to weaken aversive or traumatic memories," the researchers concluded.