Brain cells called glia act as scaffold and direct the growth of nerve fibres and their connections between specific types of neurons, scientists at Cold Spring Harbor Laboratory (CSHL) have found.
Dr. Z. Josh Huang, who led the research team behind this finding in mice, says that learning how the brain develops its complex wiring in this manner may help understand what goes wrong in disorders like autism.
The tiny gaps across which nerve cells exchange signals are called synapses, and such signals are conveyed by chemicals called neurotransmitters.
Central to the wiring architecture of the cerebellum are so-called Purkinje cells, a type of neuron that deploys a bushy array of fibres called dendrites, which extend through layers of cerebellar territory, gather signals from many other neurons in the cerebellum, and send signals to other parts of the body.
During the study, the researchers traced the sub-cellular targeting of a set of cerebellar neurons called stellate cells, which make numerous connections to the dendritic "bush" emanating from clumps of Purkinje cells.
They pointed out that such neurons require help to form synapses.
Upon labelling different cell types with chemical markers, the researchers found that non-signalling glia cells act as a scaffold, and determine where the axons emitted by the stellate cells form synapses to the Purkinje cells.
Dr. Huang says that the scaffold of glia interspersed among the neurons allows each stellate cell to make contact to many different Purkinje cells.
According to him, a direct attraction between stellate and Purkinje cells may lead two cells two pair up exclusively.
Dr. Huang's research has been published in the journal PLoS Biology.