As a psychiatrist, I’ve long wondered why some people get ill in the face of stress and adversity — either mentally or physically — while others rarely succumb.

We know, for example, that not everyone gets PTSD after exposure to extreme trauma, while some people get disabling depression with minimal or no stress. Likewise, we know that chronic stress can contribute to physical conditions like heart disease and stroke in some people, while others emerge unscathed. What makes people resilient, and is it something they are born with or can it be acquired later in life?

New research suggests that one possible answer can be found in the brain’s so-called central executive network, which helps regulate emotions, thinking and behavior. In a study published last month, Gregory Miller, a psychologist at Northwestern University, and colleagues there and elsewhere used M.R.I. to study the brains of a racially diverse group of 218 people, ages 12 to 14, living in violent neighborhoods in Chicago. They reported that the youths who had higher levels of functional connectivity in the central executive network had better cardiac and metabolic health than their peers with lower levels of connectivity.

What Dr. Miller and his colleagues discovered was that when neighborhood homicide rates went up, the young people’s cardiometabolic risk — as measured by obesity, blood-pressure and insulin levels, among other variables — also increased, but only in youths who showed lower activity in this brain network. This was true even when the researchers controlled for other factors, like psychological distress, economic status, race or ethnicity. No link was found between brain connectivity and cardiometabolic health for youths in neighborhoods with low levels of violence.