Rare mutation of gene carried by Quebec family gives insight into how the brain is wired: Brain scans could further understanding of psychiatric disorders, brain's reward system -- ScienceDailyBy scanning the brain of 20 family members who share an altered copy of DCC, the researchers found less connectivity between the areas where dopamine neurons originate (the substantia nigra and ventral tegmental area) and their target sites, such as the striatum and frontal cortex. One of these target sites -- the striatum -- was also smaller. "It's very interesting because we were able to show that this DCC gene alteration induces similar changes to the brain in both mice and humans," says Cecilia Flores. Because the brain systems affected by the gene influence responses to rewards, it was not surprising to see that the family members with the DCC mutation also have lower impulsivity traits and are less likely to smoke cigarettes. Indeed, an increasing number of studies, including those by Professor Flores' team, link DCC to psychiatric conditions. "Because the gene affects the brain's dopamine pathways, which are implicated in schizophrenia, addiction and depression, our study potentially helps us understand how these disorders arise.