Mental workout alters brain biochemistry
Actively training the working memory leads to demonstrable changes in the number of dopamine receptors in the brain, new Swedish research reveals. The study, published in the journal Science, is the first to demonstrate how mental activity can affect brain biochemistry in humans. The findings have implications for the treatment of conditions such as stroke and chronic fatigue syndrome, in which working memory is impaired.
Working memory refers to the ability to retain information for short periods of time, for example when problem solving. The messenger molecule dopamine plays a key role in this type of memory. As a neurotransmitter, dopamine's role is to ferry messages from one nerve cell to another. Disruptions to the dopamine system can damage the working memory. Impaired working memory is associated with a number of neurological and psychiatric disorders as well as normal ageing.
This latest study was led by Professor Torkel Klingberg of the Karolinska Institute in Sweden. He and his team had previously demonstrated that intensive training can lead to improvements in the working memory in just a few weeks.
Professor Klingberg and his colleagues used Positron Emission Tomography (PET scans) to measure changes in the number of dopamine receptors in the brains of the test subjects. Over a five-week period, the participants in the study carried out working memory tasks that pushed them to the limit of their working memory's ability. The volunteers worked on the tasks for just over half an hour per day.
The working memory of all participants improved significantly during the experiment. Furthermore,
the PET scans revealed that the intensive 'brain training' led to clear changes in the number of dopamine receptors in the brain's cortex.
The researchers note that their findings underline the interplay between behaviour and brain biochemistry. 'Brain biochemistry doesn't just underpin our mental activity;
our mental activity and thinking process can also affect the biochemistry,' commented Professor Torkel. 'This hasn't been demonstrated in humans before, and opens up a floodgate of fascinating questions.'
One question which remains unanswered for now is the nature of the mechanisms responsible for the brain's ability to alter the number of dopamine receptors in response to the mental training.
'Changes in the number of dopamine receptors in a person [don't] give us the key to poor memory,' explained Professor Lars Farde of the Karolinska Institute and AstraZeneca. 'We also have to ask if the differences could have been caused by a lack of memory training or other environmental factors.'
Meanwhile the researchers are optimistic that their findings could eventually lead to new treatments for people with impaired working memory resulting from ageing or conditions such as ADHD (attention-deficit hyperactivity disorder), stroke and chronic fatigue syndrome.
Professor Farde noted: 'Maybe we'll be able to find new, more effective treatments that combine medication and cognitive training, in which case we're in extremely interesting territory.'
Actively training the working memory leads to demonstrable changes in the number of dopamine receptors in the brain, new Swedish research...
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