Brainstem

Definition and function

 A brain stem is a tube-shaped mass of nervous tissue which is located at the base of the brain, superior to the spinal chord and inferior to the cerebrum⁽¹⁾ . It relays information between the brain, spinal chord, cerecellum as well as controlling eye movements and facial expressions ⁽²⁾ .

Reference

1. http://www.innerbody.com/image_nerv01/nerv46.html 

2. https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0024736/