If you were to peek inside the brai

If you were to peek inside the brain of someone who regularly smoked marijuana, you would find that it didn’t look quite like the brain of someone who didn’t smoke.

First, you might notice that a critical part of the brain that helps us process emotions and make decisions appeared smaller than in the brains of the nonsmoker.

But you would see something else, too: that the connections passing through that region of the brain were stronger and thicker.

Thankfully, you don’t have to go excavating brains anytime soon. A group of researchers has done the hard work for you. In a recent study, scientists used a combination of MRI-based brain scans to get one of the first comprehensive, three-dimensional pictures of the brains of adults who have smoked weed at least four times a week, often multiple times a day, for years.

Compared with people who don’t use, long-term, heavy marijuana smokers tend to have a smaller orbitofrontal cortex (OFC), a brain region critical for processing emotions and making decisions. But they also have more cross-brain connections that scientists think smokers may develop as a means of compensating for the difference in size.

Unlike previous research, which has looked mainly at short-term smokers or simply at young or older users, this study is one of the first to look at pot’s long-term effects on men and women between 20 and 40 years old who had smoked almost daily for between two and 30 years. The researchers looked at the brains of 110 people — 62 who didn’t smoke and 48 who did — using three different types of MRI scans.

In the smokers, these increased brain connections appeared to help them counteract the behavioral problems commonly associated with weed use, like trouble maintaining relationships or staying motivated enough to find or keep a job.