Dumbed Down By Dim

Dimly lit rooms can be more than just hard on the eyes. Michigan State University has conducted a study which suggests that spending too much time in dim lighting may actually change the brain’s structure and may decrease the ability to learn and remember.

Researchers began studying the brains of model rodents exposing them to bright and dim light for 4 weeks to examine the effects of lighting on the brain. Rodents exposed to dim lighting were found to lose about 30% of capacity in the hippocampus, responding poorly on a spatial task that the had been trained and learned previously. The hippocampus is a region in the brain that is critical for memory and learning. Rodents exposed to bright light displayed significant improvement on the spatial task. The rodent that were exposed to dim lighting were given a 4 week break period, after which when exposed to dim lighting were then exposed to bright lighting for 4 weeks their brain capacity recovered fully.

This is the first study to show changes in the environmental light can lead to structural changes in the brain. On average it is estimated that Americans spend about 90% of their time indoors according to the Environmental Protection Agency.

Sustained exposure to dim lighting led to substantial reductions in brain derived neurotrophic factor.  Brain derived neurotrophic factor is a peptide that contributes to healthy neurons and connection in the hippocampus and dendritic spines. Fewer connections were being made resulting in diminished learning and memory performance. In short the dim lights produced dumbed down, dimwits.

The hippocampus is not directly affected by light, light will act first on other sites within the brain after passing through the eyes. A group of neurons in the hypothalamus producing the peptide orexin is know to influence many brain function is being investigated by the researchers to further their findings. The study has potential implications for the elderly and individuals with glaucoma. If it is found how to directly manipulate the group of neurons it may be possible to improve cognitive functions in the elderly and those with neurological disorders, possibly even help them to recover from certain impairments and prevent further decline.