Simple X Lyrics

Lyric discussion by jirolico 

Cover art for Simple X lyrics by Andrew Bird

Serotonin is the neuron that is the center of depression problems. I see this as song as about a person with mental problems, examining the problems they have to deal with.

Serotonin is not a neuron or a type of neuron. It is a neurotransmitter, a chemical in the brain that conveys information is some way - an excitatory or inhibitory signal, usually. Serotonin is important in a variety of the brain's systems, but is especially famous for its role in mood.