Ever wondered why that friend of yours is so bright and chirpy in the morning when everyone else is groggy and short-tempered? Well, it may all be down to the way our brains are structured. Researchers from RWTH Aachen University, Germany, suggest that only ten per cent of us can be classified as true ‘morning people’, while conversely 20 per cent of us are ‘night owls’, being most active at night. The team used diffusion tensor imaging (DTI) to study the brains of both types of people and found differences in the white matter that they claim might explain higher rates of depression and a feeling of ‘chronic jetlag’ among those who often stay up late.

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