A new study shows that memory loss associated with marijuana use is caused by the drug’s interference with the brain’s natural protein synthesis machinery. Though it has been documented that marijuana impairs memory, the exact mechanism was previously unknown.

Science Daily reports that Andrés Ozaita, of the Universitat Pompeu Fabra in Spain, along with colleagues in France and Germany, focused on THC, the main psychoactive chemical compound in marijuana, which acts on a class of receptors known as cannabinoid receptors, which are known to affect the connection strength between neurons.

The researchers found that THC increases the activity of a pathway that promotes protein synthesis in the brains of mice. This transient increase of protein synthesis was mediated specifically by cannabinoid receptors expressed on the brain’s inhibitory neurons, and correlated with long-term memory deficits in mice.

The authors also found that inhibition of this signaling pathway by rapamycin, an immunosuppressant drug used to prevent organ rejection following transplantation, prevents THC-induced amnesia in mice.