'Blues' can help sufferers battle depression

Scientists found that exposure to blue light boosts activity in the parts of the brain that handle emotions and they believe the findings could explain why light appears to improve mood in both humans and animals.

Blue wavelengths within the spectral rainbow that makes up white light seem chiefly responsible for the effect, the research shows.

In the experiment, 17 healthy volunteers aged 20 to 26 listened to angry and "neutral" actors' voices while having their brains scanned. At the same time they were exposed to alternating 40 second periods of blue or green ambient light, separated by 15 to 25 seconds of darkness.

The functional magnetic resonance imaging scans showed that emotion circuits in their brains were more sensitive to shorter wavelength blue light.

Blue surroundings increased responses to emotional stimuli in the parts of the brain processing vocal sounds and memories.

Connectivity was also boosted between the voice region, the multi-functional hypothalamus, and the amygdala – an almond shaped structure known to play a key role in emotional responses.

Researchers led by Dr Gilles Vandewalle from the University of Liege in Belgium, reported the findings yesterday in the journal Proceedings of the National Academy of Sciences.