Mothers smoking marijuana during pregnancy, often risk children with behavior- and intelligence problems. A known fact, but now we are getting to know why this happens, thanks to neuroscience.

In a growing brain, new nerve-cells are constantly searching for a place and a function and they are contacting with other nerve-cells by growing their axons and synapses together in one big network. The front tip of the growing nerve-cells is being guided by so-called signal-molecules. Some of these signal-molecules are home-made endocannabinoids. The grow-cones of axons are depleted with receptors, onto where body-own endocannabinoids can bind. In a series of experiments scientists show that the grow-direction and the arise of new nerve-cells is being influenced by endocannabinoids binding to the receptors. This has been concluded in recent research by scientists of Sweden, Scotland, America, Hungaria, Germany, Italy and Japan in Science (May 25).