Brain Development
David explains how the brain develops through a process of pruning, where neurons that can't find their place commit suicide and go away. He also talks about how neurotransmission is the origin of cells communicating with each other by spitting chemicals at each other.In this clip
From this podcast

The Jordan Harbinger Show
474: David Eagleman | The Inside Story of the Ever-Changing Brain
Related Questions
Could I say that when we are in unfamiliar environments surrounded by novelty, the brain is more open to neuroplasticity and there are neurotransmitters more available to try and make sense of all the new stimuli? It's like the nervous system understands it may need to change.
How do neurons work in the context of the episode 474: David Eagleman | The Inside Story of the Ever-Changing Brain and the clip Brain Neuron Competition?