Are you always deep in thought, thinking nonstop about the world around you? You might want to cut back on that. Researchers at Harvard Medical School just published a study in the journal Nature comparing the brains of people who had died in their 60s and 70s to those who had died over the age of 100.
They found that all roads lead to REST (RE-1 Silencing Transcription), that is, a protein that helps to calm your brain. This protein is enormously important to our brain health: Defects in REST have been linked to Huntington's disease and epileptic seizures, and it's also found in reduced amounts in elderly people with Alzheimer's disease.
REST has been found to quiet brain activity, and it can also protect those with dementia and other stresses.
It is currently not possible to measure REST in a living brain, so scientists relied on donated brain tissue from hundreds of people who died from ages 60 to over 100.
Study author Bruce Yankner, professor of genetics at Harvard, found that the differences in brains were immediately compelling: The longest-living people had lower expression of genes related to neural excitation. REST regulates these genes, and the centenarians' brain cells contained higher amounts of the protein than those who died younger.
“It was extremely exciting to see how all these different lines of evidence converged,” says study co-author Monica Colaiácovo, also a professor of genetics at Harvard.
Not all thoughts are equal
Socrates would likely disagree with the notion that too much deep thinking can lead to an earlier death. (Photo: DIMSFIKAS [CC by SA 3.0]/Wikimedia Commons)
While the brain's neural activity has long been explored in issues like dementia and epilepsy, this is the first evidence to reveal how it affects human longevity.
“An intriguing aspect of our findings is that something as transient as the activity state of neural circuits could have such far-ranging consequences for physiology and life span,” says Yankner.
Besides looking at hundreds of human brain tissue samples, the Harvard team also experimented with worms and mice by decreasing and increasing their mental activity. All of these experiments found that changing neural excitations affected life spans — and creatures without the precious protein REST in their brain died at a faster rate.
It's still unclear how a person's exact thoughts, feelings or behavior can affect their longevity. Numerous studies have linked optimism to a longer life, and suggested a positive outlook can even affect your body's chemical balance.
Perhaps most striking about the study is that it contradicts many long-held popular beliefs about our brains and aging. Doctors have stressed that keeping your mind active, whether it's with brain-training games or a daily crossword puzzle, can also help you live longer. But this study's findings suggest that not all thoughts are equal.
“The completely shocking and puzzling thing about this new paper is… brain activity is what you think of as keeping you cognitively normal. There’s the idea that you want to keep your brain active in later life,” neuroscientist Michael McConnell told The Washington Post.
The researchers hope this study will encourage more research on neural overactivity and what types of therapeutic interventions are possible. But until then, just to be safe, it's probably best not to think too hard about it.