Thousands of genetic "dimmer" switches, regions of DNA known as regulatory elements, were turned up high during human evolution in the developing cerebral cortex, according to new research from the Yale School of Medicine.

Unlike in rhesus monkeys and mice, these switches show increased activity in humans, where they may drive the expression of genes in the cerebral cortex, the region of the brain that is involved in conscious thought and language. This difference may explain why the structure and function of that part of the brain is so unique in humans compared to other mammals.

The research, led by James P. Noonan, Steven K. Reilly, and Jun Yin, is published March 6 in the journal Science.

A recent study shows differences in brain structure according to how trusting people are of others.

The psychologists used two measures to determine the trust levels of 82 study participants. Participants filled out a self-reported questionnaire about their tendency to trust others. They also were shown pictures of faces with neutral facial expressions and asked to evaluate how trustworthy they found each person in the picture. This gave researchers a metric, on a spectrum, of how trusting each participant was of others.

Researchers then took MRI scans of the participants' brains to determine how brain structure is associated with the tendency to be more trusting of others. What they found were differences in two areas of the brain.

Synthetic cannabinoids ("synthetic marijuana"), with names like Spice, K2, Scooby Doo and hundreds of others, are often sold as a "legal" alternative to marijuana. Often perceived as a safe legal alternative to illicit drug use, synthetic marijuana use was associated with 11,561 reports of poisonings in the United States between January 2009 and April 2012.

Popular among teens, in 2011, synthetic marijuana was used by more than one out of ten (11.4%) high school seniors in the US, making it the most commonly used drug after real marijuana.

Sad movies are bad news for diets. A newly reported study from the Cornell Food and Brand Lab showed movie-goers watching tearjerkers ate between 28% and 55% more popcorn both in the lab and in a mall theater during the Thanksgiving holiday.

According to findings published in a JAMA Internal Medicine research letter, movie goers ate 28% more popcorn (125 versus 98 grams) when watching the tragedy Love Story than when watching the comedy Sweet Home Alabama.

Two studies scheduled for presentation at the American College of Cardiology's 64th Annual Scientific Session in San Diego failed to find a connection between testosterone therapy in men and heart problems, contradicting research that prompted the U.S. Food and Drug Administration to investigate its safety. The new studies include a meta-analysis of data from 29 studies involving more than 120,000 men and an observational study from a Wisconsin health system.

A low-cost antiseptic used to cleanse the cord after birth could help reduce infant death rates in developing countries by 12%, a systematic review published in The Cochrane Library suggests. Authors of the review found that when chlorhexidine was used on babies born outside of a hospital, it reduces the number of newborn babies who died or suffer from infections.