Researchers at Washington State University have observed cognitive changes in the offspring of rats exposed to heavy amounts of cannabis. In a summary of the research presented at the annual meeting of the Society for Neuroscience on Sunday, WSU assistant professor of Integrative Physiology and Neuroscience Ryan McLaughlin and his colleagues wrote that prenatal cannabis exposure can have long-lasting effects.
“Prenatal exposure to cannabis may cause meaningful changes in brain development that can negatively impact cognitive functioning into adulthood,” the researchers wrote.
Two-Hour Vape Sesh
To conduct the study, researchers exposed pregnant rats, known as dams, to cannabis vapor in various concentrations for two hours per day in special cages. Some rats received no vapor to serve as a control, some received vapor with no cannabis, and some with low or high amounts of cannabis. The rats were exposed to the cannabis prior to getting pregnant and throughout the gestation period.
About 60 offspring of the dams in the study were then trained to press one of two levers to receive a reward. At first, the rats received a sugar pellet for pressing the lever located near a light. The following day, the rats received the reward when they pressed either the left or right lever, without regard to the light.
The researchers found that the rats exposed to cannabis learned the first rule without difficulty. But the group that had received high levels of cannabis in the vapor “showed marked deficits in their ability to shift strategies when the new rule was implemented,” they wrote.
It appeared that the rats from mothers that had been exposed to high levels of cannabis were not able to learn the new reward strategy. They would hit the correct lever several times in