Grow your neuron as long as possible by clicking on protein targets. You can only click on protein targets within your circle of influence but you need to be quick as it decreases over time. Oh one more thing…beware of the rival red neurons that compete with you for available protein targets. ‘Axon’ uses real features of neuron development in the foetal brain. Neurons make connections by growing a single axon to contact other cells and use protein targets to navigate. Your brain is an amazing organ, with around 100 billion neurons and 100 trillion connections.