Struggling to concentrate? You might be suffering a case of winter brain drain

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 actually works differently throughout the year, with some parts far more active in the summer than in the winter months.

In fact, 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 in a way that they are not today.

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 memory-related brain activity peaked in fall and was lower near the spring equinox, potentially linked to harvest time, when food was plentiful.

Lead author Dr Christelle Meyer, of the University of Liege, said: “The present study provides compelling evidence for previously unappreciated annual variations in the cerebral activity required to sustain ongoing cognitive processes.

“Our findings indicate that, in addition to time of day, time of year influences higher cognitive brain function in healthy participants.” The research was published in the Proceedings of the National Academy of Sciences. Previous studies have shown that genes also operate at a seasonal level. For example, genes involved in immunity fire up in winter to help fight infections.