When presented with two levers, laboratory rats that were exposed to cannabis in utero were able to learn to push the one below the lightbulb that lit up. But the animals struggled to adjust their strategy when the rules of the game changed, for example, when they received a sugar reward when they pushed only the left or right lever regardless of the lightbulb. Rats born to mothers who had not inhaled cannabis were better able to learn the new strategy.
The results, presented yesterday (November 4) at the annual Society for Neuroscience conference, are “indicative of an inability to acquire and maintain a new strategy” following fetal cannabis exposure, says Hayden Wright, a PhD student in Ryan McLaughlin’s lab at Washington State University. Understanding such effects is critical as marijuana becomes legalized across the US, he adds.