The study demonstrates that THC (tetrahydrocannabinol), the main active compound of cannabis, causes a reduction in the arborization of dendrites, this “antenna network” in the extension of neurons, essential for communication between them. Consequence: this phenomenon leads to atrophy of certain regions of the cerebral cortex, a problem at an age when the brain is fully maturing. The researchers reached this conclusion by combining two complementary approaches, one in mice and the other in a group of adolescents.
“Comparing the brain to a computer, the neurons would be the central processor, receiving all the information through the synapses (connections, editor’s note) via the dendritic network,” explains Tomas Paus, professor of psychiatry and neuroscience at the University of Montreal. . “A reduction in the supply of information to the central processor by dendrites makes learning, social interactions and handling new situations more difficult. »
By analyzing magnetic resonance images (MRI) of adolescent brains, these same researchers had already noted that young people who had used cannabis before the age of 16 had a thinner cerebral cortex. But this method could not prove causality or precisely understand the effect of THC on brain cells. This is where the mouse and Graciela Pineyro’s team specializing in molecular biology come in. “This mouse model made it possible to demonstrate that THC modifies the expression of certain genes which influence the structure and function of synapses and dendrites,” she explains. This phenomenon leads to atrophy of the dendritic network, contributing to the thinning observed in certain regions of the cortex.
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Source: Destination Santé
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