Home is where the heart is, but according to multiple studies, it’s also where the brain is heavily influenced. The idea of enriched environments suggests that a positive environment has positive effects on the brain. Whether at home, in the workplace, or traveling, making your surroundings more complex and interesting can directly alter your brain. Numerous studies show that environmental complexity and stimulation bring changes in the brain. These changes extend from biochemical changes, such as increases of acetylcholine – a neurotransmitter involved in cognition – to increased branching growth of nerve cells, to neurogenesis and improved learning.Researchers tested how enriched environments affect the brain by using mice and rats to examine the effects a complex environment would have on their brains. Although they might have ended up with some spoiled rodents, the findings were extremely notable.
Donald Hebb conducted the first study in the 1940s. Hebb took home a few rats from his laboratory and began to treat them like pets. At home, he took them out of their cages, played with and allowed them to socialize with the other pet rats. The rats in the laboratory remained in standard caged environments with no opportunities for play or social engagement. Anecdotally, Hebb observed that his VIP rats showed improved behavior compared to the other rats.
After Hebb’s findings, scientists became intrigued with the enriched environment idea. At the Salk Institute, the experiment was taken a step further. They tested mice using the Morris Water Maze, a pool of opaque water with a hidden platform inside it.
First the mice “familiarized” themselves with the location of the platform. Since mice hate water, they wanted to find the platform and get out as soon as possible. The researchers then removed them from the maze and placed them inside their cages; some got a standard cage and others got the luxury living package–including a less-crowed larger cage, an exercise wheel, a variety of toys, and friends to share it all with. After spending some time in the cages, researchers once again placed the mice back in the water maze and recorded the results. The mice that were surrounded by the enriched environment consistently outperformed the caged mice, exhibiting better memory and spatial recall. In other words, the mice living in the enriched environments remembered where the platform was in the pool faster than did the traditionally housed mice.
Researchers also found that voluntary exercise (via a running wheel) increased cell proliferation in the brain and recruitment of new neurons in the dentate gyrus, a part of the hippocampus that is thought to contribute to new memories as well as other roles. Mice that had the opportunity to burn some calories on a regular basis, as well as play and socialize in their larger cages, were found by researchers to have twice as many new stem cells in their hippocampi as compared to the inactive rodents.
According to the Dana Brain Alliance, when one group of rats was genetically altered to develop Alzheimer’s disease, those exposed to an enriched environment demonstrated lower levels of Alzheimer’s indications (levels of amyloid peptides and plaques). These findings suggest that exposure to an enriched environment may actually counteract a physiological predisposition to the disease.
These findings support the “arousal response theory,” the idea that an enhanced environment stimulates the mice and rats, creating a positive effect on the brain.
How do these lucky rats living the good life affect us as humans? Well it turns out that, on a cellular and molecular level, human brains and rodent brains are not all that different. So keep this in mind the next time you’re debating between the gym and a nap, or a group outing and the couch; these studies show that the environment we surround ourselves with can have a direct effect on our brains.
One way to enhance your environment is to engage in brain-stimulating hobbies. Click here to check out a list of some of the things you could be doing right now!
Hebb, D.O. (1974). The effects of early experience on problem-solving at maturity. Am. Psychology, 2, 306-307.
Kempermann, G, Kuhn, H. G. & Gage, F. H. (1997). More hippocampal neurons in adult mice living in an enriched environment. Nature 386, 493-495.
Patoine, B. (2006). Evidence grow for brain benefits of enriched environments in normal aging and disease. The Dana Foundation. Retrieved from http://www.dana.org/printerfriendly.aspx?id=7142
Van Praag, H., Kempermannn, G. & Gage, F. H. (1999). Running increases cell proliferation and neurogenesis in the adult mouse dentate gyrus. Nature Neuroscience 2, 226-270.