Did you play video games when you were a child? They weren’t around until I was in college. But nowadays, kids all over the country are spending a lot of time in front of the TV or computer, playing those games.

That’s a big change. And with the arrival of ever-better technologies, video games are increasingly vivid, realistic - and addicting.  

I’ve wondered for years whether playing these games influences brain development. I think it might make a kid’s brain work faster, able to process more visual information. And my nine-year-old son seems to be able to multitask in ways I can’t. But I’ve also wondered if there’s a dark side to brain development, induced by the shocking brutality in some of the videos. Now, for the first time, I’ve found new evidence that violent video games do alter brain functioning.

Researchers at Indiana University in Indianapolis used Magnetic Resonance Imaging (MRI) to map out which parts of the brain are stimulated when kids play different types of video games. One group of adolescents played a violent game called "Medal of Honor," while another group played an equally exciting but non-violent game called "Need for Speed." After 30 minutes, doctors collected the MRI data.

The teens playing the non-violent game showed activity in the frontal area of the brain. This is the area associated with concentration, inhibition, and self-control. The teens playing the violent video game showed no activity in the frontal area of the brain. Instead, the game activated their amygdala. This is the "reptilian" brain that’s associated with emotional arousal - especially anger.

This study is sobering for a number of reasons. The reptilian, or limbic, brain is the least cerebral and most animal-like part of the brain. It’s where your most basic instincts reside. Instincts to do with things like feeding, survival, and procreation.

This works well in times of crisis. If you’re starving, your reptilian brain will drive you to find food. If someone is chasing you and you’re in danger, this part of your brain will put you into "fight or flight" mode. In other words, to protect yourself, you’ll either become violent or you’ll run for your life.

But this area of your brain has no capacity for logic, reason, or objective decision-making. It has no way to express tolerance, understanding, or love. Now consider that millions of teenagers are over-stimulating this portion of their brain for hours every day.

Cause for concern? I think so. Because other research has shown that both repetitive actions and repetitive thoughts hardwire your brain, reinforce whatever actions or thoughts you’re practicing, and make it more likely you’ll repeat them in the future.

What do I mean by "hardwire"? There are connections between your brain cells that are called dendrites. Repeated activities stimulate dendrites and create neural pathways between different parts of your brain. The more you practice a certain activity, the stronger that neural pathway becomes. These structural changes are the physical mechanisms of learning.

And your brain, like the rest of your body, follows the "use it or lose it" rule. Neural pathways that are not being used eventually get "pruned."