Action video gaming can do your brain more harm than good. Neuroscientists at Université de Montréal and McGill University find that habitual players have less gray matter in their hippocampus, putting them at higher risk of developing brain disorders ranging from depression to Alzheimer’s disease. This result comes as a surprise, since previous studies have shown a benefit to certain brain processes such as visual attention and short term memory. New research techniques are helping to fill in the picture of gaming’s effect on the overall brain. In this case, the study researchers conducted a full neuro-imaging study that scanned the brains of habitual players of action video games and those of non-players in two longitudinaal studies. They found less gray matter in the hippocampus of habitual players and determined that, over time, it was indeed the gaming that led to the brain differences in the two groups. So what is the real impact on the brains of gamers? The hippocampus is the center of spatial memory and episodic memory. Spatial memory helps us orient ourselves and episodic memory helps us to remember past experiences. A previous study of taxi drivers, for example, shows them to have more developed hippocampi, which means a healthier brain overall. However, the caudate nucleus, a sort of auto-manager that is part of the brain’s striatum counterbalances the hippocampus. This part of the brain helps us form habits like remembering how to ride a bicycle or get home from work, and reminds us when it’s time to eat, drink, have sex and other activities central to our well-being. Prior studies show that gaming stimulates the caudate nucleus more than it does the hippocampus. Researchers in this study confirm that this process causes the hippocampus to lose cells and atrophy. Our brains are delicately balanced and young adults especially should be aware that improving some cognitive skills may come at a long-term cost to their overall brain power.