Poly-innervated neuromuscular junctions

Confocal image of axons making contact with muscle fibres at neuromuscular junctions. Initially, as seen here, more than one nerve fibre contacts each muscle fibre. As development proceeds, the mature innervation pattern is established where only one motor axon contacts each muscle fibre. This transition is called synapse elimination and is thought to involve of competition between the neurons. The neurotransmitter acetylcholine (red) sends the signals from the nerve to makes the muscle contract. Biomedical Image Awards 2002.