Unconscious learning uses old parts of the brain

Apr 06, 2010

(PhysOrg.com) -- A new study from the Swedish medical university Karolinska Institutet provides evidence that basic human learning systems use areas of the brain that also exist in the most primitive vertebrates, such as certain fish, reptiles and amphibians. The study involved an investigation into the limbic striatum, one of the evolutionarily oldest parts of the brain, and the ability to learn movements, consciously and unconsciously, through repetition.

"Our results strongly substantiate the theories that say that the implicit, by which I mean non-conscious, learning systems of the brain are simpler and evolutionarily older," says Associate Professor Fredrik Ullén from Karolinska Institutet and the Stockholm Brain Institute.

Many of the mundane skills that we apply every day, such as buttoning up a shirt or playing an instrument, comprise a sequence of discrete movements that must be carried out in the correct order. Scientists have long known that there are two learning systems for such patterns of movement; with the implicit system, we learn without being aware of the fact and without conscious training, such as through simple repetition. The explicit system, on the other hand, we use when we consciously train and are aware of what we are learning.

A structure that is involved in learning and motor control is the basal ganglia, which lie deep in the cerebral hemispheres. Dopamine, a substance used in the transmission of signals between neurons, is important for learning and the plasticity of the basal ganglia.

In the present study, which is published in PNAS, the journal of the American Academy of Sciences, researchers have examined both the implicit and explicit learning of motor sequences in relation to the number of dopamine D2 receptors in the basal ganglia. While they found a correlation between D2 receptor density and both forms of learning, they also noted that the evolutionarily oldest part of the basal ganglia - the limbic striatum - was only involved in implicit learning.

"In other words, we probably have certain fundamental learning systems in common not only with rats, mice and other mammals, but also with the most primitive vertebrates, which also have a limbic striatum," says Dr Ullén.

In the future, a better understanding of how these learning systems work can be of use in developing new treatments for diseases such as Parkinson's and Huntington's, which are characterised by disorders of basal ganglia function and impaired motor skills.

Explore further: New research supporting stroke rehabilitation

More information: Anke Karabanov, Simon Cervenka, Örjan de Manzano, Hans Forssberg, Lars Farde & Fredrik Ullén, Dopamine D2 receptor density in the limbic striatum is related to implicit but not explicit movement sequence learning, PNAS, online early edition 5 - 9 April 2010

Related Stories

Songbirds reveal how practice improves performance

Jul 06, 2009

(PhysOrg.com) -- Learning complex skills like playing an instrument requires a sequence of movements that can take years to master. Last year, MIT neuroscientists reported that by studying the chirps of tiny ...

Why we learn more from our successes than our failures

Jul 29, 2009

(PhysOrg.com) -- If you've ever felt doomed to repeat your mistakes, researchers at MIT's Picower Institute for Learning and Memory may have explained why: Brain cells may only learn from experience when we ...

Recommended for you

New research supporting stroke rehabilitation

18 hours ago

Using world-leading research methods, the team of Dr David Wright and Prof Paul Holmes, working with Dr Jacqueline Williams from the Victoria University in Melbourne, studied activity in an area of the brain ...

Team finds an off switch for pain

23 hours ago

In research published in the medical journal Brain, Saint Louis University researcher Daniela Salvemini, Ph.D. and colleagues within SLU, the National Institutes of Health (NIH) and other academic institutions have d ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.