The human brain contains more than 100 trillion (1014) synaptic connections, which form all of its neural circuits. Neuroscientists have long been interested in how this complex synaptic web is weaved during development and remodelled during learning and disease. Recent studies have uncovered that glial cells are important regulators of synaptic connectivity. These cells are far more active than was previously thought and are powerful controllers of synapse formation, function, plasticity and elimination, both in health and disease. Understanding how signalling between glia and neurons regulates synaptic development will offer new insight into how the nervous system works and provide new targets for the treatment of neurological diseases.
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We acknowledge all of our colleagues whose important work was not directly cited here because of space limitations. This work is referenced in the review articles cited here. C.E. is supported by the Alfred P. Sloan Foundation and a Klingenstein Fellowship Award in the Neurosciences, from the Esther A. & Joseph Klingenstein Fund.
The authors declare no competing financial interests.
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