Enriching experiences and learning opportunities don’t just make life more satisfying — they might make your brain more resistant to addiction. So suggests a study published in the October 2015 edition of the journal Neuropharmacology. Researchers based in the University of California, Berkeley compared the drug-seeking behavior of mice kept in a deprived environment with mice that had been through a cognitive training session in which they’d been challenged to play, learn and explore. The team discovered that even relatively brief cognitive training made the mice less likely to seek the solace of substances — in this case, cocaine. Because mice and human brains share similarities, the researchers hope “positive new learning experiences might also help to promote resilience in people who are at risk for substance use disorders,” said Josiah Boivin, the lead author of the study and a candidate in the neuroscience PhD program at the University of California, San Francisco. Boivin conducted the research at UC Berkeley as part of his thesis work. Senior author Linda Wilbrecht, PhD, assistant professor of psychology and neuroscience at UC Berkeley, wrote a paper on the study that appears in Neuropharmacology.
Promoting Resilience
An inspiration to the research, Boivin said, was environmental enrichment literature that’s helped scientists understand that experiences appear to shape the brain’s reward systems, for better and for worse. For example, a well-known research project known as the “rat park” study, published in 1978 in the journal Psychopharmacology, found that rats kept in lab cages with nothing to stimulate them could easily drug themselves to death if given the opportunity. But put rats in a “rat park” that allows them to play, mate, explore, learn and form connections, and substances lose much of their appeal. “Building on this literature, we sought to develop a brief intervention that would promote resilience in animals who were otherwise vulnerable to drug-seeking behavior because of their living conditions (i.e., standard lab housing),” Boivin said. “We wanted … an intervention that could be implemented in a brief time frame. We also sought an intervention that could have long-lasting effects even after the intervention ended.” The Berkeley researchers got all three, confirming that substances are less alluring to a brain that’s been stimulated and challenged and that even a brief session of cognitive training was enough to make a lasting difference. It’s evidence that “individual levels of vulnerability and resilience to addiction are not necessarily immutable,” Boivin said. “Rather, interventions can promote resilience.”
Learning to Like Drugs Less
For the study, the researchers kept one group of mice confined to cages with limited opportunities for activity and on a restricted diet. Meanwhile, another group of mice were put through a nine-day cognitive training program that included a variety of enrichment activities, such as learning new ways to win a Honey Nut Cheerio. A group of mice yoked to the trained mice got a treat whenever their counterparts did, but they didn’t have to meet a challenge to get their snack. When the cognitive training ended, all the mice stayed in their home cages for a month. For the next phase of the study, the mice were allowed to individually explore two chambers that had different smells and textures. When it was clear which chamber each mouse preferred, the researchers began giving the mice injections of cocaine in the opposite chamber. Later, the mice were given mock injections to simulate the handling they’d received earlier and were allowed to return to the chambers. All headed straight for the room they associated with cocaine. But as time went on and the testing continued, the mice that had undergone the cognitive training showed less preference for the cocaine-related chamber. The report concluded based on this tendency that “deprivation may confer vulnerability to drug-seeking behavior and that brief interventions may promote long-term resilience.” Particularly exciting to the researchers was that the benefits of the cognitive training session appeared to have staying power. Even though the mice had spent four weeks in relative deprivation in their cages after the cognitive training, the positive effect they derived from it didn’t wear off. Boivin noted that the study looked only at the effects of cognitive training in mice before they were exposed to drugs. “An important future complement to this research would be to test the effects of cognitive training in animals that were already exposed to drug,” he said. If the same results were found, those findings would raise hope that the lure of substance use could be lessened through cognitive enrichment, even after addiction has taken hold. By Kendal Patterson Follow Kendal on Twitter at @kendalpatterson
