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Struggling to concentrate? It could be winter brain drain

By Sarah Knapton SCIENCE EDITOR Proceedings of the National Academy of Sciences.

IF EVERY task seems that little bit harder in the dark days of winter, it may not be just your imagination.

Scientists have discovered that the brain works differently through the year, with some parts far more active in the summer than winter.

Brain activity related to attention and concentration peaks during the summer solstice and slumps to a low on the shortest day of the year.

Researchers at the University of Liege in Belgium believe that it is a remnant of ancient rhythms when humans were highly attuned to the seasons. For example, the brain takes a lot of energy to run, so when food was scarce in the winter, it would make sense to dial down the parts that were not absolutely necessary to survival.

When food was plentiful, such as at harvest time, higher brain functions, such as working memory, which is needed for reasoning, comprehension and learning, would be given a boost.

“Humans were very dependent on seasons a few thousand years ago so it is not surprising to see seasonality in humans, as in most species,” said Dr Gilles Vandewall. “The mechanism may therefore be a remnant of ancestral rhythmicity.

“Because the means at disposal to complete cognitive processes is lower in winter, it could feel harder to complete them or there may be additional compensatory mechanism that take place and cost more.”

Although mood changes have been linked to seasons before, it is the first study to show that mental functions follow similar patterns.

Researchers measured the brain function of 28 volunteers each month. During testing, each participant spent 4.5 days in a laboratory so their bodies would not get seasonal cues, such as daylight.

At the end of the 4.5 days, scientists scanned their brains while they took part in two mental tasks, one to test memory and one to test attention span.

Brain activity related to attention peaked in June near the summer solstice and was lowest near the winter solstice. Working memoryrelated brain activity peaked in autumn and was lower near the spring equinox, potentially linked to harvest time, when food was plentiful.

The research was published in the





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