Researchers at Karolinska Institutet in Stockholm, Sweden, have shown for the first time that the active training of the working memory brings about visible changes in the number of dopamine receptors in the human brain, according to a study published this month in Science.
The study was conducted with the help of PET scanning, which provides insight into the complex interplay between cognition and the brain's biological structure.
"Brain biochemistry doesn't just underpin our mental activity; our mental activity and thinking process can also affect the biochemistry," said lead author Professor Torkel Klingberg. MD, PhD. "This hasn't been demonstrated in humans before, and opens up a floodgate of fascinating questions."
The neurotransmitter dopamine plays a key part in many of the brain's functions. Disruptions to the dopamine system can impair working memory, making it more difficult to remember information over a short period of time. Impaired working memory has, in its turn, proved to be a contributory factory to cognitive impairments in such disorders as ADHD and schizophrenia.
Klingberg and colleagues have previously shown that the working memory can be improved with a few weeks' intensive training. Through a collaborative project conducted under the Stockholm Brain Institute, the researchers have now taken a step further and monitored the brain using PET scans, and confirmed that intensive brain training leads to a change in the number of dopamine D1 receptors in the cortex.
Their results could be significant to the development of new treatments for patients with cognitive impairments, such as those related to ADHD, stroke, chronic fatigue syndrome and aging.
"Changes in the number of dopamine receptors in a person doesn't give us the key to poor memory," said Lars Farde, MD, PhD, one of the researchers who took part in the study. "We also have to ask if the differences could have been caused by a lack of memory training or other environmental factors. 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."