the.com/mesencephalon
The brain's ancient traffic cop, routing sight, sound, and movement before you're even aware.
means The midbrain — the small, ancient segment of the brainstem that relays visual, auditory, and motor signals between the forebrain and spinal cord.
from Built from Greek mesos ('middle') plus enkephalos ('brain,' literally 'that which is inside the head'), compounded by anatomists who needed a precise name for the middle portion of the three primary brain vesicles that form in early development — forebrain, midbrain, hindbrain. The 'mes-' shows up elsewhere marking middles (Mesopotamia, the land 'between rivers'), while enkephalos survives in encephalitis and encephalogram.
- also called
- midbrain, same structure
- houses
- substantia nigra, dopamine's home base
- evolutionary age
- present in fish, 500 million years old
- handles
- reflexive eye and head movement toward stimuli