Remember Eternal Sunshine of the Spotless Mind?
The 2004 science fiction movie starring Jim Carrey and Kate Winslet featured a bickering couple dealing with the consequences of having their respective memories of each other erased through a radical procedure. While no real-life equivalent exists, yet, a new research study in Nature Neuroscience suggests that electroshock therapy (ECT) can be used to reduce negative memories in patients suffering from depression. Though ECT has long been linked to reports of memory loss in patients undergoing treatment, the procedure described in the new study involved strategically timed ECT bursts that could target and disrupt disturbing memories.
According to lead researcher Marijn Kroes of Radboud University Nijmegen in the Netherlands, the study is based on the theory of memory reconsolidation in which specific memories are retrieved from storage each time they are used and then "re-written" back into the brain's memory over time. According to previous memory reconsolidation research, memories being reconsolidated are vulnerable and can even be erased by electric shock. Using 42 patients who had been prescribed ECT for severe depression, Kroes and his team presented two disturbing slide-shows, one of a car accident and the other of a physical assault. They then "reactivated" the memory by playing part of one of the slide shows for each patient. Afterward, during the period when the memory was being reconsolidated, the patient received the prescribed ECT session.
When tested on the following day, patients were given a multiple choice memory test for both slide shows. Though patients were able to recall the non-reactivated story, their memory for the story for which they had received the reactivating slideshow (and subsequent ECT) was significantly poorer. When the memory test was given only 90 minutes after the ECT however, recall for both stories was essentially the same. Based on these results, ECT appears to block memory reconsolidation rather than simply causing memory loss. It also suggests that there may be a "window of opportunity" for dealing with unwanted memories.
While Kroes stresses that ECT may not be the best therapy for most patients, these results could lead to less invasive ways of blocking memory reconsolidation and may even be used to block memories associated with posttraumatic stress disorder, addiction, and other disorders linked to unwanted memories.
"The ability to permanently alter these types of memories might lead to novel, better treatments," Kroes stated.