Releasing the brakes for learning

Learning can only occur if certain neuronal "brakes" are released. As the group led by Andreas Lüthi at the Friedrich Miescher Institute for Biomedical Research has now discovered, learning processes in the brain are dynamically regulated by various types of interneurons. The new connections essential for learning can only be established if inhibitory inputs from interneurons are reduced at the right moment. For some years, most neurobiologists studying learning processes have assumed that the new connections required for learning can only be established and ultimately reinforced if certain neuronal "brakes" are released - a process known as disinhibition. It has also been supposed for some time that various types of interneurons could be involved in disinhibition. Interneurons are nerve cells that surround and - via their connections - inhibit the activity of principal neurons. It has not been clear, however, whether these cell types actually play a role in disinhibition and how they control learning.