Some people like to do something with dim lights on as they feel comfortable with low “mood lighting,” particularly in the office. However, a new study shows that exposing oneself to dim light for hours could diminish the brain capacity.
The study funded by the National Institutes of Health involved animal model such as the Nile grass rats, yet the result of this study could also apply to humans. Nile grass rats usually sleep at night and active during the day just like humans.
Neuroscientists from Michigan State University examined the brains of Nile grass rats and exposed them to dim and bright light for four weeks. The results showed that those mice exposed to dim light had reduced brain capacity by about 30 percent. This part of the brain refers to the hippocampus, which is a critical area for learning and memory. The researchers discovered that these rodents performed poorly on a spatial task they had given.
Meanwhile, those mice exposed to bright light had shown enhancement on the particular task. However, when the mice exposed to dim light then exposed to bright light for another four weeks, their hippocampus capacity had recovered, according to Medical Xpress.
The study indicates that changes in the environmental light could alter the structure of the brain. Exposure to dim light could significantly reduce the brain-derived neurotrophic factor, which is a peptide that makes the connections, neurons and hippocampus healthy. It also diminishes the dendritic spine connections (the tiny protrusions near the solid green line, which is the dendrite, as shown in the image below), which make neurons communicate with one another. The scientists also think that the light acts on the other parts of the brain first before it will affect the hippocampus after passing through the eyes, according to New Atlas.
Antonio “Tony” Nunez, psychology professor and co-investigator of the study said that when they exposed the rats to the dim light, mimicking the cloudy days of Midwestern winters or typical indoor lighting, the animals performed severely in spatial learning. He further said that this is similar to when people could not find their way back to their cars in a busy parking lot after spending a few hours in a shopping mall or movie theater.