23 December 2013
Nature: Electroconvulsive therapy (ECT), better known as electroshock therapy, developed a poor reputation early in its use, but it has regained popularity as a treatment of last resort for severe depression when paired with anesthesia and muscle relaxants. Now Marijn Kroes of Radboud University Nijmegen in the Netherlands and his colleagues are examining whether ECT can be used to eliminate depressive memories. The theory of memory reconsolidation proposes that memories are taken out of storage when they are retrieved and then rewritten into the brain's circuits, but they may be vulnerable to changes or erasure while out of storage. Kroes's team showed a pair of disturbing slideshow narratives to 42 patients who were receiving ECT for clinical depression. After replaying one of the slideshows for each patient, the team immediately administered ECT. One day later when quizzed on the slideshows, the patients had a hard time remembering the show they viewed twice, while they answered questions about the other slideshow significantly better. However, Kroes and his team found that ECT did not affect the patients' memories if they were quizzed 90 minutes after the treatment. This suggests that the treatment affects only the long-term memory reconsolidation process and does not cause short-term memory loss. Kroes says that further study is need to determine the long-term efficacy of the treatment and whether it works on real-life memories that have been stored for long periods of time.