BBC Monday, 4 June, 2001, 23:34 GMT 00:34 UK

Thinking 'drains the brain'

Glucose provides fuel for the brain Scientists have come up with proof that too much thinking can be exhausting.

The impact of straining the grey matter is likely to be more pronounced in older people.

A team from the University of Illinois in the US carried out research on rats.

They found that concentration drains glucose from a key part of the brain in the animals.

However, the effect was more dramatic in older rats, whose brains also took longer to recover.

Researcher Professor Paul Gold said the findings may have important implications for the way schools schedule classes and meals.

He believes they may also help scientists to develop a better understanding of age-related deficits in memory and learning.

Runs on glucose

Fellow researcher Dr Ewan McNay, of Yale University, said: "The brain runs on glucose.

"Young rats can do a pretty good job of supplying all the glucose that a particular area of the brain needs until the task becomes difficult.

"For an old rat given the same task, the brain glucose supply vanishes out the window. This correlates with a big deficit in performance. A lack of fuel affects the ability to think and remember."

Glucose, a naturally occurring sugar in the blood, is the main source of energy for brain.

It has long been thought that, unless a person is starving, the brain always receives an ample supply of glucose.

However, Professor Gold and Dr McNay measured glucose levels in the brain cells of rats as they negotiated their way through a maze.

They found that in those cells concerned with orientation glucose levels dipped by 30%.

However, levels stayed constant in other brain cells that played no role in orientation.

In a follow up study, the researchers showed that in older rats glucose levels in the active brain cells dropped by 48%, and that recovery took 30 minutes.

However, in younger rats levels fell by only 12%, and recovered quickly.

Injections

The researchers found they could boost the performance of the older rats by giving them glucose injections.

Professor Gold said: "Glucose enhances learning and memory not only in rats but also in many populations of humans.

"For schoolchildren, this research implies that the contents and timing of meals may need to be co-ordinated to have the most beneficial effects that enhance learning."

Dr Tonmoy Sharma, of the Institute of Psychiatry, told BBC News Online: "We all get exhausted by thinking, so it makes intuitive sense that glucose levels are depleted when we do.

"However, making cross-species generalisations has always been a problem."

Dr Sharma said there was also evidence that thinking became slower when blood sugar levels were down.

The research appeared in the journal Neurobiology of Learning and Memory.

-- Anonymous, June 04, 2001

Answers

Does this mean that I should have a candy bar when I think too much?? Sounds good to me ! ! !

-- Anonymous, June 04, 2001