Central nervous system (CNS)
Refers to the brain and the spinal cord.

Orphan disease
An orphan disease is defined as one affecting fewer than five in 10,000 people in the European Union and fewer than 200,000 people in the United States.

Stem cell
A cell with the ability to self-renew and to differentiate into specialized cells, tissues and organs.

Therapeutic neurogenesis
The process of generating new neurons from endogenous neural stem cells to treat diseases of the CNS.