In a step forward in learning how a developing brain is built, researchers have identified a group of proteins that programme a common type of brain nerve cell to connect with another type of nerve cell in the brain.The study provides an intriguing glimpse into the processes that establish connections between the nerve cells in the brain."We are now looking at how loss of this wiring affects brain functions in mice," said Azad Bonni, head of department of anatomy and neurobiology at Washington University's school of medicine in St. Louis.Bonni is studying synapses in the cerebellum - a region of the brain that sits in the back of the head.The cerebellum plays a central role in controlling the coordination of movement.New results show that a complex of proteins known as NuRD (nucleosome remodelling and deacetylase) plays a fairly high supervisory role in some aspects of the cerebellum's construction.When the researchers blocked the NuRD complex, cells in the cerebellum called granule cells failed to form connections with other nerve cells.These circuits are important for the cerebellum's control of movement coordination and learning."The NuRD complex not only affects the activity of genes directly, it also controls other regulators of multiple genes," Bonni informed.The findings may help understand the causes of intellectual disability and autism, said the study appeared in the journal Neuron.