Does stupid dim light make us stupid?

Persistent weak light affects the brain of rats

Light can massively affect health and mood. "In the dark, it's easy to cheat," says the vernacular, but scientists suggest in a recent study that permanent dim light can damage the brain. The researchers are investigating the influence of too little light on the brain and thinking in diurnal rats. The rodents were exposed for weeks to a dim light, as a result of their learning and memory waned. The scientists now suspect that this may also be the case in humans if they spend too much time in poorly lit rooms and offices.

The researchers studied the brains of Nilegrass rats, which, like humans, are diurnal and sleep at night. The rodents were exposed to low light for four weeks. Within this period, the rats lost about 30 percent of their capacity in the hippocampus. This brain region is responsible for learning and memory. The rats showed significantly worse performance in solving an already trained spatial task than before the influence of dim light. The research team led by Joel Soler of Michigan State University in East Lansing recently published their study results in the journal "Hippocampus".

Researchers discovered that rats suffer cognitive loss from prolonged dim light. Does that also count for people? (Image: pathdoc / fotolia.com)

A light cure negated the changes

A control group of the rats was exposed to bright light. This group achieved significantly higher performance in the same task. The animals, which were previously exposed to the bad light, recovered by a four-week light cure completely back from their reduced brain capacity and brought back full power in the tasks.

Why people can not find their cars anymore

This is the first such study to show that changes in ambient light can lead to structural changes in the brain. If these findings are confirmed in humans, this could have massive consequences. Americans spend an average of 90 percent of their time indoors, according to the US Environmental Protection Agency. Psychology professor and co-researcher Antonio Nunez compares the results in rats to human behaviors: "It's similar to when people can not find their way back to their cars after spending hours in a mall or movie theater in a busy car park."

Dim light creates stupidity

Joel Soler, PhD in psychology and lead author of the study, explains that faint light leads to a decrease in a peptide in the brain that helps to maintain healthy connections and neurons in the hippocampus. "Because fewer connections are made, this leads to decreased learning and memory performance, which depends on the hippocampus," Soler explains in a press release from the university on the study results. "In other words, dim light creates stupidity," says Soler.

The results enable new approaches

The researchers discovered a potential site in rodent brains that produce a peptide called orexin, which is known to affect a variety of brain functions. In further studies, the scientists want to clarify whether administering orexin to the rats exposed to bad light will help their brains recover.

New therapies for neurological diseases?

The project could also affect the elderly and people with glaucoma, retinal degeneration or cognitive impairment. Further investigation will determine whether orally administered orexin is useful for improving cognitive function in the aging population and reversing neurological disorders or preventing progression. (Vb)