Recent research has uncovered some fascinating links between sunlight exposure and brain function, particularly in how it might enhance our ability to learn. One key discovery involves the role of ultraviolet (UV) light (known for helping our bodies produce vitamin D) and how it triggers a biochemical pathway in the brain that can boost cognitive functions, like memory and motor learning.
When our skin is exposed to UV rays, it increases levels of a compound called urocanic acid (UCA) in the bloodstream. The research found that UCA travelled to the brain – crossing the blood-brain barrier – and, once there, converted into glutamate, a neurotransmitter that plays a major role in communication between neurons. This process, triggered by UV exposure, led to an increase in glutamate levels in certain parts of the brain, like the motor cortex and hippocampus, which are crucial for motor learning and memory.
In experiments, animals showed significant improvement in their ability to learn new tasks, like balancing on a rotating rod (a test of motor coordination), and demonstrated better recognition memory (preferring a new object over a familiar one) after being exposed to UV light. This enhancement in learning and memory was linked to the increased glutamate levels in the brain, which facilitated stronger communication between neurons.
Researchers injected UCA directly into the bloodstream of test subjects, which replicated the results from UV exposure, showing that it was the UCA, as opposed to the actual exposure to sunlight, that drove the brain’s enhanced performance. This discovery points to a whole new biochemical pathway that connects sunlight exposure to brain activity and learning.
Of course, too much exposure to the sun can be harmful, so it’s important to follow health guidelines when in direct sunlight, but moderate UV exposure can have beneficial effects on the brain. This is especially true in the context of seasonal changes; many people experience a dip in mood and energy during the autumn and winter months, when we don’t see the sun as often. This phenomenon – seasonal affective disorder (SAD) – may be related to a lack of UV exposure.
Phototherapy, which involves exposure to bright light, has been shown to alleviate symptoms of SAD, and these findings may explain, in part, why sunlight can have such a profound impact on mood and mental performance.
So, moderate sunlight exposure may offer more than just a mood boost. It appears to enhance cognitive function, including memory and motor learning, by triggering a biochemical pathway that increases glutamate in the brain. In other words, solar power is great for learning, because it radiates knowledge!
Sources: Sunlight Brightens Learning and Memory – ScienceDirect, Sunlight And the Brain | Science | AAAS