If you’ve ever felt more alert and focused after stepping out into bright daylight, there’s a scientific explanation for that. New research shows that exposure to higher levels of light can directly impact activity in a key region of the brain – the hypothalamus – in ways that enhance cognitive performance and wakefulness.
The study, published in the journal eLife, represents a major leap forward in understanding the biological effects of light on human behavior and brain health. While previous research has shown that light exposure increases alertness, this is one of the first studies to pinpoint how it influences the human brain at the neural level.
“Translating findings on how light exposure affects the brain in animal models to humans is a difficult process, as the later maturation of the cortex in human beings enables much more complex cognitive processing,” explains lead author Islay Campbell from the University of Liège in Belgium, in a statement. “In particular, the question of whether hypothalamus nuclei contribute to the stimulating impact of light on cognition is not established.”
For the study, Campbell’s team recruited 26 healthy young adults to perform cognitive tasks in an MRI scanner while exposed to different levels of light – from complete darkness up to extremely bright illumination. The auditory tasks tested executive functioning (like working memory) and emotional processing.
Using a technique called ultra-high resolution 7 Tesla functional MRI, which provides enhanced brain imaging, the researchers examined how changing light levels affected activity in specific regions of the hypothalamus during the tasks. Their findings revealed a striking pattern.
