Researchers found that by strategically timing electroconvulsive (ECT) or electroshock therapy bursts they could target and disrupt a bad memory being experienced by a patient.
Marijn Kroes, a neuroscientist at Radboud University Nijmegen in the Netherlands, and his colleagues based their research on the memory reconsolidation theory. It proposes that after memories are accessed they have to be re-written into the brain. Tests on animals and limited evidence from humans have shown that during this 'rewriting' process memories are vulnerable and can be altered or erased.
The theory was tested on 42 patients who were prescribed ECT. The patients were shown two disturbing slide shows: one was of a car accident and the other was a physical assault. The patients were later asked to recall one of the memories and immediately given ECT.
One day later they were asked multiple choice questions about the the slideshows, and were significantly worse at answering questions about the slideshow that was "erased," while they were able to answer questions about the slideshow that wasn't.
Patients who were asked the questions 90 minutes after the procedure were better at answering, suggesting that ECT didn't induce a sudden memory loss and rather blocked the time-dependent consolidation of memories.
Further research is required to determine how long this erasure lasts and whether it will work on deep-seated long-term memories.
Kroes said that while this may not be the best option for most patients, it would go along way to help developing less intrusive methods or targeting memories in the process of reconsolidation.