When a person decides to make a change and follows through with action, that process alters the brain’s neural circuitry, which defines how neurons communicate.

Neuroscientists have studied what happens in our brains when we are engaged in an internal struggle over whether to indulge, for instance, in a tempting piece of cake or to resist that temptation and choose a healthy snack such as fresh fruit instead.

Such choices are controlled in the prefrontal cortex — the front part of the brain that regulates most decision making.

In one study, Cendri Hutcherson and her colleagues at the California Institute of Technology used MRI scanning to track the neural circuits that control self-regulation, as well as those that work to sabotage attempts to adopt healthier behaviors.

When a research volunteer chooses the tempting sugar-laden cake, the prefrontal ventromedial region (in the middle of the forehead just above the eyes) takes charge.

But when the volunteer places more value on health than on taste and resists the sugary temptation, the dorsolateral area (near the temples) takes control.

This same process occurs whether the behavior involves smoking, alcohol binges, drug use, or avoiding exercise. Many people have difficulty changing unhealthy habits and resisting the influence of the ventromedial cortex.

Thankfully, self-help strategies, psychotherapy, support groups, and other approaches can heighten people’s awareness of their problems and allow them to break long-term habits. Doing so actually adjusts the brain’s neural circuitry, making it easier to stick with new healthy choices.

That means changing your behavior literally changes your brain.