Once the subject of kooky Jim Carrey/Kate Winslet movies, the selective erasure of specific memories from our brains has become altogether more feasible. But how exactly does it work? And, if this indeed becomes a reality, should we engage it, and who exactly will benefit?
Joe Tsien and his team of neuroscientists at the Medical College of Georgia, Augusta, and collaborators in Shanghai have succeeded in erasing specific memories from the minds of mice.
First, the mice were genetically engineered to produce much higher levels of a protein called alpha-calmodulin kinase II [CaMKII], an enzyme which is expressed in the brain and involved in long-term potentiation [LTP], the physiological basis of learning and memory formation. The levels of expression could be returned to normal by administering a drug. The scientists began their experiments by administering electrical shocks and loud sounds to the mice while they were in a training chamber. Upon returning to the chamber an hour later, the mice in the control group froze up with fear, but the mice with boosted levels of CaMKII remained calm. The genetically altered mice showed the same lack of fear even a month later.
The selective erasure of specific memories from our brains has become altogether more feasible. But how exactly does it work?
A similar observation was made in experiments involving the mice’s recognition of specific objects. In those cases, over expression of CaMKII appeared to eliminate all memory of toys with which the mice had previously been exposed. Alteration of memory formation and consolidation is not a new development in neuroscience – studies on rats have already demonstrated that this is possible. However, this study went one step further and demonstrated the possiblity of erasing a traumatic memory after it had been formed. In a later phase of the study, by prodding the mice to retrieve traumatic memories, and simultaneously overexpressing CaMKII, the scientists seemed to erase the memory completely, whilst leaving other memories intact.
Scientists are cautious about the potential of this new information to be used in human studies. Mice are a useful experimental model of humans, especially in neuroscience research, but the authors of this study stress that memory in humans is far more complex than in mice. However, the therapeutic implications of such research are interesting and varied.
Consider post-traumatic stress disorder [PTSD] – whereby traumatic events can be relived again and again, resulted in an anxiety disorder. Currently, PTSD is treated with antidepressants and anxiolytics, as well as cognitive therapy, but all of these have a limited success rate, and PTSD is still regarded as debilitating.
Is this approach even ethical? If experience shapes our personality, and memory is the facilitator of this personal growth, then is it wise to erase memories that are unpleasant?
It can also increase risk for heart disease and high blood pressure. Some experimental approaches involve treatment with MDMA [ecstasy] and propanolol. Propanolol can be used shortly after the traumatic event, to reduce its impact and the potential onset of PTSD. MDMA is thought to reduce activity in the left amygdala [the area of the brain responsible for fear and anxiety], allowing sufferers to explore the traumatic event in a new light, free from the associated anxiety. But could it be possible to even eliminate the memories themselves?
This approach has already been considered by the US military to minimise aftercare costs of soldiers returning from the Iraq war. Up to 12% will suffer from the condition, and psychiatric treatment is expensive, especially to a government body which consistently runs over budget.
This, of course, raises some thorny questions. Is this approach even ethical? If experience shapes our personality, and memory is the facilitator of this personal growth, then is it wise to erase memories that are unpleasant? Or, more pertinently, memories which we deem unpleasant? Will it result in our histories endlessly repeating themselves [as in Eternal Sunshine], or, if the technology falls into the wrong hands, being completely rewritten?
Tsien himself is cautious. “All memories, even very painful emotional memories, have their purposes. We learn from those experiences to avoid making the same kind of mistake.”
