Research from Washington State University is contributing to new findings about the possible effects of cannabis on our brains.
Ryan McLaughlin, an assistant professor of integrative physiology and neuroscience, was a presenter at the Society for Neuroscience’s annual meeting in November.
The world’s largest neuroscience conference in San Diego included a variety of discussions and findings about how cannabis can impact the brain throughout life, positively and negatively.
Researchers also looked at how cannabis affected different demographic groups, including women, teens, newborns, and seniors.
McLaughlin and fellow researchers Hayden R. Wright, Jacqulyn R. Kuyat, Joshua W. Rodriguez, and Janelle M. Lugo focused on how the behavior of offspring of rats differed if the mother was exposed to different amounts of cannabis while pregnant.
The research found that the offspring from mothers who were exposed to the highest amounts were more likely to have trouble adjusting their strategies in order to receive rewards.
“Prenatal exposure to cannabis may cause meaningful changes in brain development that can negatively impact cognitive functioning into adulthood,” he wrote. “This work sets the foundation for future studies that will examine changes in the brain that might underlie these alterations.”
Public health officials, including the Spokane Regional Health District, have made efforts to educate pregnant and breastfeeding mothers about the risks of using cannabis.
In some cases, the women may use it out of habit, lack of knowledge, or with the mistaken belief that it will reduce the nausea of morning sickness since it is known to reduce nausea for other conditions.
Cannabis is also the most commonly used illicit substance reported among pregnant women
The WSU experiment provided varying amounts of cannabis vapor to rats for two hour-long sessions each day during their pregnancy period. The amount of THC in each dose compared to a few puffs for a human.
Their 80 offspring were tested in how they responded to changes in procedure of pulling two levers in order to receive a sugar reward.
The research found that all the rats learned the correct process and were able to shift strategies as needed. But the ones whose mother was exposed to the highest amounts “would not keep to the strategy long enough to strike the right lever,” compared to the ones who had a parent who received less or no cannabis.
“The general take-home message is that we see deficits, particularly in the domain of cognitive flexibility, in rats prenatally exposed to high doses of cannabis vapor,” McLaughlin said. “The impairment is not a general learning deficit, as they can learn the initial rule just fine. The deficit only emerges when the learned strategy is no longer resulting in reward delivery.”
McLaughlin notes that the high-exposure rats may not necessarily be less intelligent, just less motivated. They could be less interested in the task, not want the reward as much, or want to explore other avenues for treats.
Other findings at the scientific gathering reported by Medical News Today that cannabis use can disrupt communication between different sections of the brain, interfere with learning and memory, and affect activity.
But at the same time, other research indicated that it can reduce physical short- and long-term pain, and decrease symptoms of dementia such as Alzheimer’s disease.
Another rat study indicated that early exposure to cannabis made rats more sensitive to stress, along with less self-control than rats not exposed to cannabis.
While the society members acknowledged that more people have begun accessing cannabis products for medical and recreational uses in the last five years, they caution that there is very little information and even basic scientific understanding about long-term effects through someone’s life.
The presentation concluded with a call for more research into possible negative and positive effects, especially in teens, women, pregnant women and chronic pain sufferers.
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