Neuroscientists at the Massachusetts Institute of Technology (MIT) have published a study regarding a new drug that can assist sufferers of post-traumatic stress disorder (PTSD) in making their unwanted memories disappear.
This discovery is expected to be used in therapies with PTSD patients who cannot overcome difficult emotions.
The drug tested is an HDAC2 inhibitor that proved in laboratory experiments to erase traumatic memories in rats.
Researchers applied attention to chromatin modifications that can happen when previously held memories are erased.
Rats were reconditioned using mild electro-shocks which lead to their indifference to being shocked. Thus they were no longer in fear of the outcome.
This was accomplished because within 24 hours of the experiment, the rats had extensive chromatin which was influential in the reconditioning process.
Once this occurred, the rats could be placed back under the conditions that previously had invoked fear – which now had no effect on their emotions.
The team at MIT showed that “re-exposure to a fearful memory opens a window of opportunity during which the memory can be altered, but only if the memory has recently been formed. If you do something within this window of time, then you have the possibility of modifying the memory or forming a new trace of memory that actually instructs the animal that this is not such a dangerous place.”
Li-Huei Tsai, lead author of the study and director of the Picower Institute for Learning and Memory (PILM), said : “By inhibiting HDAC2 activity, we can drive dramatic structural changes in the brain. What happens is the brain becomes more plastic, more capable of forming very strong new memories that will override the old fearful memories.”
Tsai pointed out: “If you do something within this window of time, then you have the possibility of modifying the memory or forming a new trace of memory that actually instructs the animal that this is not such a dangerous place. However, the older the memory is, the harder it is to really change that memory. Our experiments really strongly argue that either the old memories are permanently being modified, or a new much more potent memory is formed that completely overwrites the old memory.”
Perfecting this type of drug and giving it to human patients who are combining this therapy with psychiatric visits, could enhance the effects of the treatment; or so say the team at MIT.
In December of 2013, neuroscientists at Radboud University Nijmegen (RUN) in the Netherlands have discovered that when the electrical current in the human brain is intercepted, it can lead to erasing memories.
During the experiment, researchers exposed subjects to a distressing story, and then revisited it a week later while combining electroconvulsive therapy which completely wiped out the memory.
Marijn Kroes, lead author of the study, took advantage of patients who were currently receiving electroshock therapy for depression and were not responding to pharmacological or psychological treatment.
Through questionnaires, the team was able to show that “participants who received ECT seemed to have no memory of the story they had been reminded of — they scored a 25 percent on a four-answer multiple choice test, the same as guessing at random. The same participants showed significantly better recall — 35 percent — of the second, non-triggered story. ECT, in other words, selectively erased the memories that were being actively recalled.”
Kroes hopes this new information can be used for patients diagnosed with post-traumatic stress disorder (PTSD).
He said: “Just to be clear: it’s a long way from being an actual clinical application. A lot of experimental, fundamental science is often very difficult to translate into the real world.”
Using electroshocks during the experiment should not be viewed with 40 year old stigma, according to Kroes.
Daniela Schiller, neuroscientist at Mount Saini School of Medicine in New York commented : “It’s a very elegant paper, compelling data, and it’s a difficult study to do. It’s very impressive they managed to do that, and that they even tried.”
Schiller has conducted experiments showing that people can learn to erase the emotional attachment to a memory which breaks the cycle of fear attached to those memories.
Over 40 years ago, Donald Lewis, experimental psychologist, preformed a study involving trained rats who were conditioned to fear a designated sound which became inconsequential after receiving electroshocks to the brain which erased their previous conditioning.
They were no longer afraid of the sound.