Grey Area: Dr. John Howland on Cannabis & Budding Brains

A behavioural neuroscientist in Saskatoon is uncovering marijuana's effects on fetal brain development.  After recently winning a five-year CIHR grant of $960,076 in the spring of 2024, Dr. John Howland's lab at the University of Saskatchewan is expanding its work examining prenatal exposure to cannabis smoke. Howland's teams will assess the way cannabis exposure alters higher brain functions like memory and learning in both rats and mice. Compared to cannabis injections in the past, the professor of Anatomy, Physiology and Pharmacology at the College of Medicine said exposing rodents to high-potency smoke for up to 15 minutes at a time provides a more realistic picture of marijuana's effects on fetal brain development.  Over their lives, Howland will measure changes in cortical limbic circuitruity, for both rodent mothers and their offspring.  "The cortex is definitely involved, but we also look at other areas like the hippocampus and the amygdala," said Howland. "There's pretty good evidence that they are at least subtly affected after gestational exposure to cannabis." Now, it's a matter of quantifying which circuits cannabis affects in the rodent brain — under circumstances as close to real-life human exposure as Howland's laboratory can create.  "It's not simple," said Howland. He notes a wide variety of phenotypes of THC and CBD strains are now available at retailers, each with its own characteristics and potential interactions with neurons.  "These receptors are involved in many discrete events during brain development," he said. "We're hoping to be more controlled and more specific."  Howland's team is also searching for ways to stem damage from high-potency strains, while exploring therapies like exercise to counteract cannabis exposure and help future generations grow healthier brains.   He said cannabis may be legal -- but that does not make it safe. "It turns out a lot of things that are legal like alcohol and tobacco aren't that safe during pregnancy either," said Howland. "I think more knowledge has to be helpful as women make these decisions for themselves."