Abnormal pruning of neuronal connections might stall brain maturation, resulting in reduced brain connectivity and even behaviours linked to disorders such as autism.

Cornelius Gross at the European Molecular Biology Laboratory in Monterotondo, Italy, and his colleagues studied mice that were engineered to have fewer microglia — non-neuronal brain cells that trim back synapses, or neuronal connections, during brain development. These animals had fewer synapses between neurons and decreased connectivity between brain regions, and seemed to be less social in behavioural tests.

Microglia and synaptic pruning are important for normal brain development, and problems with this pruning could lead to neurodevelopmental disorders, the authors say.

Nature Neurosci. http://doi.org/rbf (2014)