A new study on how brain retains powerful role of memory among addicts will throw light on the mechanism to make drug addiction less compulsive, said Washington State University researchers.
Turning off the mechanism found by these researchers may help in “diminishing the emotional impact or the emotional content of the memory, so it decreases the motivation to relapse,” said Barbara Sorg, a professor of neuroscience at Washington State University, Vancouver.
Memories of drug use rekindle the urge to become impulsive drug addicts and the brain plays a major role to reinforce these memories, in part by giving them emotional weight to do what they did in the past. Drug use, in particular, creates memories so powerful that they hijack the system, turning physiology into pathology, said these researchers. “If you saw ‘Spinal Tap,’ it’s like memory turned up to 11,” said Sorg.
Sorg and her doctoral candidate Megan Slaker gave male rats cocaine in a specific setting, a drug cage, making them feel familiar with the experience in that place. Every time they are given the dose, the rats would draw memories of previous experiences there, reconsolidate them with new information and in effect reinforce the memory, said the finding.
With one group of rats, the researchers removed structures called perineuronal nets that surround a group of neurons in the medial prefrontal cortex, in the brain that is key for attention, cognition and inhibitory behavior, besides learning and memory. The nets which were regulating the ability to strengthen or weaken as memories are recalled and reconsolidated in the experiment.
The rats with their nets removed were less interested in being in the drug cage than others.
“When we manipulated them and removed these nets from the prefrontal cortex, we saw that our animals had poorer memories,” said Slaker. “That was a very novel finding since no one else has ever looked at these structures within the prefrontal cortex in relation to a drug memory.”
Sorg underscores the fact that the procedure may not have erased the drug memory but blunted its emotional power. More than that, the finding opens new avenue of developing a way to target a protein of the perineuronal nets, to counteract cocaine’s influence over addicts’ memories, said Sorg, whose findings are published in the Journal of Neuroscience.
Other co-suthors of the paper include Lynn Churchill, Ryan Todd, Jordan Blacktop, and researchers at the Oregon Health and Science University and the University of Wyoming. Funding came from the National Institutes of Health and NASA.