It may not be a good idea to frequently stay in dimly-lit rooms. Findings of a new study suggest that dim light can change the structure of the brain and impair a person's ability to learn and remember.

In a new study published in the journal Hippocampus, Joel Soler, from the Michigan State University, and colleagues studied the brains of Nile grass rats. Just like humans, these animals are active during the day and sleep at night.

Effects Of Bright And Dim Lights On Memory And Learning

After exposing the rodents to dim and bright lights over a period of four weeks, researchers found that those exposed to dim light lost 30 percent of capacity in the hippocampus, the region of the brain that plays a critical role in learning and memory.

The animals also performed poorly on a spatial task that they were previously trained on. The animals that were exposed to bright light, however, were found to have significant improvements in spatial task.

After four weeks, the animals that were earlier exposed to dim light were exposed to bright light for another four weeks. The researchers found that the brain capacity of the animals and their capacity to perform tasks recovered fully.

"The results illustrate that not only does light intensity affect cognitive performance, but that it also impacts hippocampal structural plasticity," the researchers wrote in their study.

How Dim Light Affect Memory And Learning

The researchers explained that sustained exposure to dim light can lead to significant reduction of the brain-derived neurotrophic factor or BDNF, which helps support the brain's neurons so they grow more quickly and develop stronger connections.

Exposure to dim light also reduces the dendritic spines that transmit messages between neurons. Soler explained.that fewer connections can result in diminished learning and memory performance.


The findings could have implications for the elderly, many of whom suffer from dementia, a condition marked by a progressive decline in a person's mental ability, as well as people with cognitive impairments.

Knowing how environmental light affects memory and the structure of the brain could pave way for measures that can help the aging population and those with neurological disorder recover from impairment or prevent further decline.

"A mechanistic understanding of the effects of light on cognition can help to identify risk factors for cognitive decline and contribute to the development of more effective prevention and treatment of cognitive impairment in clinical populations," Soler and colleagues said.

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