AC-1 and synaptic development.

Across many developing brain structures, axons initially grow toward, and synapse exuberantly with, target neurons before the later removal of excess inputs. In many cases, this input pruning leads to a remarkable specificity, where a single target is innervated by only one axon. This phenomenon has been observed at the neuromuscular junction, the climbing fibre to Purkinje cell synapse in the cerebellum, and also at relay synapses in the thalamus.