September 5, 2024
Study Links Electric Light to Brain Changes in Spiders
Researchers find reduced brain volume in spiders exposed to electric light at night
A recently published study by researchers at the University of Melbourne has shed new light on how exposure to electric light during nighttime can affect brain structures in animals. Although the study primarily focused on the Australian garden orb-weaving spider (Hortophora biapicata), its findings raise potential questions about how electric lighting in urban environments may impact other species, including humans.
The study, led by Nikolas J. Willmott and published in Biology Letters, found that spiders exposed to electric light at night experienced reductions in the volume of brain structures related to vision. Notably, these changes were detected in the primary eye visual pathway, a key region responsible for processing visual information. While the effects observed in spiders were subtle, the implications of this study extend beyond the invertebrate world.
The study highlights the potential for electric light to disrupt neurological functions through mechanisms that may be shared across species, including oxidative stress and reduced melatonin production, both of which are critical to brain health.
Brain Structure Changes in Spiders
The researchers used micro-CT imaging to examine brain volume changes in spiders exposed to electric light during late juvenile development. They found that spiders exposed to 20 lux of cool-white LED light for more than a month had significantly smaller brain structures in the primary visual pathways compared to spiders kept in a dark environment.
The study’s authors noted that these brain volume reductions were likely caused by either oxidative stress or changes in neural investment, a phenomenon where certain neural tissues decrease in size due to environmental factors. This finding adds to the growing body of evidence that electric lighting can have wide-ranging effects on brain structures, particularly those associated with vision.
Co-author Dr. Kathryn B. McNamara highlighted that the spiders' brains exhibited plasticity in response to electric light, with the most significant reductions occurring in structures responsible for visual processing. "The study provides insight into how the urban environment, specifically electric lighting, can influence neural structures in species that have adapted to these conditions," McNamara said.
Implications for Other Species
The findings from this study on spiders contribute to ongoing research into how electric light affects the brain, particularly in urban areas where night-time illumination is prevalent. While the experiment focused on invertebrates, other studies on vertebrates, including birds and mammals, suggest that the mechanisms observed in spiders may also apply to larger animals.
In humans, electric light at night has been linked to disruptions in melatonin production, which can lead to increased oxidative stress in the brain. Melatonin, a hormone responsible for regulating sleep-wake cycles, acts as an antioxidant, reducing oxidative damage in neural tissues. Prolonged exposure to electric light at night has been shown to disrupt melatonin production, potentially contributing to cognitive impairments, mood disorders, and other neural issues.
Urban Lighting and Future Research
As electric light becomes more widespread in urban environments, its impact on wildlife and human health continues to be a growing area of concern. The study’s authors call for further research into the long-term effects of electric lighting on neural structures across different species, including more detailed studies on human health outcomes. The authors conclude that reductions in brain volume observed in the spiders, particularly in regions linked to melatonin synthesis and visual processing, highlight the need for further investigation into how electric lighting could affect cognitive functions in other animals.
While the specific impact of electric lighting on human brains is still under investigation, this study offers a glimpse into how even brief periods of exposure can have measurable effects on neural health. For lighting industry professionals, these findings highlight the importance of considering how lighting systems are designed and deployed, especially in urban environments where electric light is a constant presence.
