[neuro] working memory training boost count of dopamine receptors

[Eugen Leitl]

http://www.sciencedaily.com/releases/2009/02/090206081507.htm

Cognitive Training Can Alter Biochemistry Of The Brain

Torkel Klingberg. (Credit: Ulf Sirborn)

ScienceDaily (Feb. 6, 2009) — Researchers at the Swedish medical university
Karolinska Institutet 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. The study, which is published in the journal
Science, was conducted with the help of PET scanning and provides deeper
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," says
Professor Torkel Klingberg, who led the study. "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,
such as when problem solving. Impaired working memory has, in its turn,
proved to be a contributory factory to cognitive impairments in such
disorders as ADHD and schizophrenia.

Professor Klingberg and his 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
Positron Emission Tomography (PET scans), and have confirmed that intensive
brain training leads to a change in the number of dopamine D1 receptors in
the cortex.

Their results can be of significance to the development of new treatments for
patients with cognitive impairments, such as those related to ADHD, stroke,
chronic fatigue syndrome and ageing.

"Changes in the number of dopamine receptors in a person doesn't give us the
key to poor memory," says Professor Lars Farde, 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."

Positron Emission Tomography is a medical imaging technique based on the
decay of radioactive isotopes that is able to produce three-dimensional
pictures of the movement of signal substances in the living body. Karolinska
Institutet has been able to invest in the world's most powerful PET scanner
for brain imaging thanks to a financial contribution by pharmaceutical
company AstraZeneca.

Journal reference:

   1. Fiona McNab, Andrea Varrone, Lars Farde, Aurelija Jucaite, Paulina
Bystritsky, Hans Forssberg and Torkel Klingberg. Changes in Cortical Dopamine
D1 Receptor Binding Associated with Cognitive Training. Science, 6 February
2009

Adapted from materials provided by Karolinska Institutet.