A new study shows how different regions of the brain produce 鈥渞adically different鈥� effects from cannabis use, which may explain why people have such varied reactions to the drug.
鈥淯ntil now, it was unknown which specific regions of the brain were responsible for these highly divergent effects of marijuana,鈥� said study lead and Western University professor Dr. Steven Laviolette in a release.
The study, published in Scientific Reports, said that tests performed on rodents 鈥渋dentified highly specific target regions in the brain鈥� that controlled the 鈥渞ewarding鈥� properties of cannabis versus the negative side-effects associated with the drug.
Laviolette, along with postdoctoral fellow Dr. Christopher Norris, studied the effects of THC, the main psychoactive compound in cannabis, on a rat鈥檚 brain and found that it can produce 鈥渉ighly rewarding鈥� effects in the region of the brain known as the nucleus accumbens.
The nucleus accumbens is an interior structure of the brain that plays a significant role in the cognitive production of motivation, reinforcement learning and addiction.
The positive or 鈥渞ewarding鈥� effects of cannabis on the nucleus accumbens were only noted on the front portions of the structure; in contrast, THC in the rear area of this region in the brain produced 鈥渉ighly aversive effects鈥� including 鈥渋ncreased schizophrenia-related cognitive and emotional symptoms.鈥�
鈥淭hese findings are important because they suggest why some people have a very positive experience with marijuana, when others have a very negative experience,鈥� said Norris in a news release.
The researchers said the differences between individual responses to marijuana is likely due to genetics, as that can determine how different parts of the nucleus accumbens are more sensitive than others.
