Marijuana use may affect decision-making areas in teen brains | Science News for Students

Marijuana use may affect decision-making areas in teen brains

Giving adolescent rats a pot-like compound damaged protective 'nets' around nerve cells
Jan 7, 2019 — 6:45 am EST
an illustration of the brain as a blue wireframe

Using a marijuana-like drug during adolescence may damage decision-making structures in the brain, a new study finds.


SAN DIEGO, Calif. — Teen use of marijuana may change the brain in key decision-making areas. That’s the finding of a new study in rats.

“Adolescence is a dangerous time to be insulting the brain,” says Eliza Jacobs-Brichford. This, she adds, is especially true for use of pot and other “drugs of abuse.”

Jacobs-Brichford works at the University of Illinois at Chicago. As a behavioral neuroscientist, she studies links between the brain and behavior. In the new study, her team gave adolescent rats a chemical that mimics the effects of marijuana. Later, the researchers found changes in parts of the brain involved in making decisions.

Normally, many of the affected cells are covered by sturdy webs. These are called perineuronal (PAIR-ih-nurr-OHN-ul) nets. The rigid structures help stabilize links between cells. But adolescent male rats treated with the drug had fewer nerve cells covered by the protective nets. The drug exposure didn’t seem to affect the nets in female rats.

Jacobs-Brichford presented her team’s findings November 7. She spoke, here, at the annual meeting of the Society for Neuroscience.

Power Words

(more about Power Words)

adolescence     A transitional stage of physical and psychological development that begins at the onset of puberty, typically between the ages of 11 and 13, and ends with adulthood. Children and young adults in this phase are known as adolescents.

annual     Adjective for something that happens every year. (in botany) A plant that lives only one year, so it usually has a showy flower and produces many seeds.

behavior     The way something, often a person or other organism, acts towards others, or conducts itself.

cell     The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall.

chemical     A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.

link     A connection between two people or things.

marijuana     A mind-altering drug. It is made from the leaves (and sometimes stems or seeds) of the Cannabis sativa plant. This drug also goes by the colloquial terms pot and weed.

nerve     A long, delicate fiber that transmits signals across the body of an animal. An animal’s backbone contains many nerves, some of which control the movement of its legs or fins, and some of which convey sensations such as hot, cold or pain.

neuroscience     The field of science that deals with the structure or function of the brain and other parts of the nervous system. Researchers in this field are known as neuroscientists.

pot     A slang term for marijuana.


Meeting:​​ E. Jacobs-Brichford et al. Effects of adolescent WIN exposure on perineuronal net emergence in PFC. Society for Neuroscience Annual Meeting. San Diego, California. November 7, 2018.